Version bump

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

.gitignore

@@ -15,3 +15,4 @@ build/
 *.iml
 *.jks
 keystore.properties
+package-info.java

.idea/codeStyles/Project.xml

@@ -94,6 +94,8 @@
       <option name="XML_LEGACY_SETTINGS_IMPORTED" value="true" />
     </XML>
     <codeStyleSettings language="JAVA">
+      <option name="METHOD_ANNOTATION_WRAP" value="0" />
+      <option name="FIELD_ANNOTATION_WRAP" value="0" />
       <arrangement>
         <groups />
         <rules>

app/build.gradle

@@ -1,4 +1,5 @@
 apply plugin: 'com.android.application'
+apply from: 'nonnull.gradle'
 
 // Create a variable called keystorePropertiesFile, and initialize it to your
 // keystore.properties file, in the rootProject folder.
@@ -10,14 +11,15 @@ android {
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8
     }
-    compileSdkVersion 27
+    compileSdkVersion 28
     dataBinding.enabled true
     defaultConfig {
         applicationId 'com.wireguard.android'
         minSdkVersion 21
-        targetSdkVersion 27
-        versionCode 432
-        versionName '0.0.20180711'
+        targetSdkVersion 28
+        versionCode 439
+        versionName '0.0.20180826'
+        buildConfigField 'int', 'MIN_SDK_VERSION', "$minSdkVersion.apiLevel"
     }
     // If the keystore file exists
     if (keystorePropertiesFile.exists()) {
@@ -39,10 +41,20 @@ android {
     buildTypes {
         release {
             if (keystorePropertiesFile.exists()) signingConfig signingConfigs.release
+            externalNativeBuild {
+                cmake {
+                    arguments "-DANDROID_PACKAGE_NAME=${android.defaultConfig.applicationId}"
+                }
+            }
         }
         debug {
             applicationIdSuffix ".debug"
             versionNameSuffix "-debug"
+            externalNativeBuild {
+                cmake {
+                    arguments "-DANDROID_PACKAGE_NAME=${android.defaultConfig.applicationId}${applicationIdSuffix}"
+                }
+            }
         }
     }
     externalNativeBuild {
@@ -56,6 +68,9 @@ ext {
     databindingVersion = '3.1.3'
     supportLibsVersion = '27.1.1'
     streamsupportVersion = '1.6.0'
+    jsr305Version = '3.0.2'
+    zxingEmbeddedVersion = '3.6.0'
+    acraVersion = '5.2.0-rc2'
 }
 
 dependencies {
@@ -65,8 +80,11 @@ dependencies {
     implementation "com.android.support:design:$supportLibsVersion"
     implementation "com.android.support:preference-v14:$supportLibsVersion"
     implementation "com.android.support:support-annotations:$supportLibsVersion"
+    implementation "com.google.code.findbugs:jsr305:$jsr305Version"
+    implementation "com.journeyapps:zxing-android-embedded:$zxingEmbeddedVersion"
     implementation "net.sourceforge.streamsupport:android-retrofuture:$streamsupportVersion"
     implementation "net.sourceforge.streamsupport:android-retrostreams:$streamsupportVersion"
+    implementation "ch.acra:acra-http:$acraVersion"
 }
 
 tasks.withType(JavaCompile) {

app/nonnull.gradle

@@ -0,0 +1,87 @@
+/*
+ * Copyright © 2018 Eric Kuck <eric@bluelinelabs.com>.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+task generateNonNullJavaFiles(dependsOn: "assembleDebug", type: Copy) {
+    group = "Copying"
+    description = "Generate package-info.java classes"
+
+    def basePackage = "com" + File.separatorChar + "wireguard"
+    def mainSrcPhrase = "src" + File.separatorChar + "main" + File.separatorChar +
+            "java" + File.separatorChar
+    def mainTestSrcPhrase = "src" + File.separatorChar + "test" + File.separatorChar +
+            "java" + File.separatorChar
+    def mainAndroidTestSrcPhrase = "src" + File.separatorChar + "androidTest" + File.separatorChar +
+            "java" + File.separatorChar
+
+    def sourceDir = file( "${projectDir}" + File.separatorChar + "src" + File.separatorChar +
+            "main" + File.separatorChar + "java" + File.separatorChar +
+            basePackage )
+    def testSourceDir = file( "${projectDir}" + File.separatorChar + "src" + File.separatorChar +
+            "test" + File.separatorChar + "java" + File.separatorChar +
+            basePackage)
+    def androidTestSourceDir = file( "${projectDir}" + File.separatorChar + "src" + File
+            .separatorChar +
+            "androidTest" + File.separatorChar + "java" + File.separatorChar +
+            basePackage )
+
+    generateInfoFiles(sourceDir, mainSrcPhrase);
+    sourceDir.eachDirRecurse { dir ->
+        generateInfoFiles(dir, mainSrcPhrase)
+    }
+    if (file(testSourceDir).exists()) {
+        generateInfoFiles(testSourceDir, mainTestSrcPhrase);
+        testSourceDir.eachDirRecurse { dir ->
+            generateInfoFiles(dir, mainTestSrcPhrase)
+        }
+    }
+    if (file(androidTestSourceDir).exists()) {
+        generateInfoFiles(androidTestSourceDir, mainAndroidTestSrcPhrase);
+        androidTestSourceDir.eachDirRecurse { dir ->
+            generateInfoFiles(dir, mainAndroidTestSrcPhrase)
+        }
+    }
+    println "[SUCCESS] NonNull generator: package-info.java files checked"
+}
+
+private void generateInfoFiles(File dir, String mainSrcPhrase) {
+    def infoFileContentHeader = getFileContentHeader();
+    def infoFileContentFooter = getFileContentFooter();
+    def infoFilePath = dir.getAbsolutePath() + File.separatorChar + "package-info.java"
+
+    //file(infoFilePath).delete(); //do not use in production code
+    if (!file(infoFilePath).exists()) {
+        def infoFileContentPackage = getFileContentPackage(dir.getAbsolutePath(), mainSrcPhrase);
+        new File(infoFilePath).write(infoFileContentHeader +
+                infoFileContentPackage + infoFileContentFooter)
+        println "[dir] " + infoFilePath + "  created";
+    }
+}
+
+def getFileContentPackage(String path, String mainSrcPhrase) {
+    def mainSrcPhraseIndex = path.indexOf(mainSrcPhrase)
+    def output = path.substring(mainSrcPhraseIndex)
+
+    // Win hotfix
+    if (System.properties['os.name'].toLowerCase().contains('windows')) {
+        output = output.replace("\\", "/")
+        mainSrcPhrase = mainSrcPhrase.replace("\\", "/")
+    }
+
+    return "package " + output.replaceAll(mainSrcPhrase, "").replaceAll(
+                "/", ".") + ";\n"
+}
+
+def getFileContentHeader() {
+    return  "/**\n" +
+            " * Make all method parameters @NonNull by default.\n" +
+            " */\n" +
+            "@NonNullForAll\n"
+}
+
+def getFileContentFooter() {
+    return  "\n" +
+            "import com.wireguard.util.NonNullForAll;\n"
+}
+

app/src/main/AndroidManifest.xml

@@ -4,6 +4,7 @@
     package="com.wireguard.android"
     android:installLocation="internalOnly">
 
+    <uses-permission android:name="android.permission.CAMERA" />
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
@@ -50,6 +51,11 @@
             android:label="@string/create_activity_title"
             android:parentActivityName=".activity.MainActivity" />
 
+        <activity
+            android:name="com.journeyapps.barcodescanner.CaptureActivity"
+            android:screenOrientation="fullSensor"
+            tools:replace="screenOrientation" />
+
         <receiver android:name=".BootShutdownReceiver">
             <intent-filter>
                 <action android:name="android.intent.action.ACTION_SHUTDOWN" />

app/src/main/java/com/wireguard/android/Application.java

@@ -5,45 +5,118 @@
 
 package com.wireguard.android;
 
+import android.content.Context;
+import android.content.Intent;
 import android.content.SharedPreferences;
+import android.content.pm.PackageManager;
+import android.content.pm.Signature;
 import android.os.AsyncTask;
+import android.os.Build;
 import android.os.Handler;
 import android.os.Looper;
 import android.preference.PreferenceManager;
+import android.support.annotation.Nullable;
 import android.support.v7.app.AppCompatDelegate;
 
 import com.wireguard.android.backend.Backend;
 import com.wireguard.android.backend.GoBackend;
 import com.wireguard.android.backend.WgQuickBackend;
-import com.wireguard.android.configStore.ConfigStore;
 import com.wireguard.android.configStore.FileConfigStore;
 import com.wireguard.android.model.TunnelManager;
 import com.wireguard.android.util.AsyncWorker;
 import com.wireguard.android.util.RootShell;
 import com.wireguard.android.util.ToolsInstaller;
 
+import org.acra.ACRA;
+import org.acra.annotation.AcraCore;
+import org.acra.annotation.AcraHttpSender;
+import org.acra.data.StringFormat;
+import org.acra.sender.HttpSender;
+
+import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.lang.ref.WeakReference;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.concurrent.Executor;
+import java.security.cert.CertificateFactory;
+import java.security.cert.X509Certificate;
 
+import java9.util.concurrent.CompletableFuture;
+
+
+@AcraCore(reportFormat = StringFormat.JSON,
+        buildConfigClass = BuildConfig.class,
+        logcatArguments = {"-b", "all", "-d", "-v", "threadtime", "*:V"},
+        excludeMatchingSharedPreferencesKeys = {"last_used_tunnel", "enabled_configs"})
+@AcraHttpSender(uri = "https://crashreport.zx2c4.com/android/report",
+        basicAuthLogin = "6RCovLxEVCTXGiW5",
+        basicAuthPassword = "O7I3sVa5ULVdiC51",
+        httpMethod = HttpSender.Method.POST,
+        compress = true)
 public class Application extends android.app.Application {
-    private static WeakReference<Application> weakSelf;
-    private AsyncWorker asyncWorker;
-    private Backend backend;
-    private RootShell rootShell;
-    private SharedPreferences sharedPreferences;
-    private ToolsInstaller toolsInstaller;
-    private TunnelManager tunnelManager;
-    private Handler handler;
-    private Collection<BackendCallback> haveBackendCallbacks = new ArrayList<>();
-    private final Object haveBackendCallbacksLock = new Object();
+    @SuppressWarnings("NullableProblems") private static WeakReference<Application> weakSelf;
+    @SuppressWarnings("NullableProblems") private AsyncWorker asyncWorker;
+    @SuppressWarnings("NullableProblems") private RootShell rootShell;
+    @SuppressWarnings("NullableProblems") private SharedPreferences sharedPreferences;
+    @SuppressWarnings("NullableProblems") private ToolsInstaller toolsInstaller;
+    @SuppressWarnings("NullableProblems") private TunnelManager tunnelManager;
+    @Nullable private Backend backend;
+    private final CompletableFuture<Backend> futureBackend = new CompletableFuture<>();
 
     public Application() {
         weakSelf = new WeakReference<>(this);
     }
 
+    /* The ACRA password can be trivially reverse engineered and is open source anyway,
+     * so there's no point in trying to protect it. However, we do want to at least
+     * prevent innocent self-builders from uploading stuff to our crash reporter. So, we
+     * check the DN of the certs that signed the apk, without even bothering to try
+     * validating that they're authentic. It's a good enough heuristic.
+     */
+    @SuppressWarnings("deprecation")
+    @Nullable
+    private static String getInstallSource(final Context context) {
+        if (BuildConfig.DEBUG)
+            return null;
+        try {
+            final CertificateFactory cf = CertificateFactory.getInstance("X509");
+            for (final Signature sig : context.getPackageManager().getPackageInfo(context.getPackageName(), PackageManager.GET_SIGNATURES).signatures) {
+                try {
+                    for (final String category : ((X509Certificate) cf.generateCertificate(new ByteArrayInputStream(sig.toByteArray()))).getSubjectDN().getName().split(", *")) {
+                        final String[] parts = category.split("=", 2);
+                        if (!"O".equals(parts[0]))
+                            continue;
+                        switch (parts[1]) {
+                            case "Google Inc.":
+                                return "Play Store";
+                            case "fdroid.org":
+                                return "F-Droid";
+                        }
+                    }
+                } catch (final Exception ignored) { }
+            }
+        } catch (final Exception ignored) { }
+        return null;
+    }
+
+    @Override
+    protected void attachBaseContext(final Context context) {
+        super.attachBaseContext(context);
+
+        if (BuildConfig.MIN_SDK_VERSION > Build.VERSION.SDK_INT) {
+            final Intent intent = new Intent(Intent.ACTION_MAIN);
+            intent.addCategory(Intent.CATEGORY_HOME);
+            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
+            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+            startActivity(intent);
+            System.exit(0);
+        }
+
+        final String installSource = getInstallSource(context);
+        if (installSource != null) {
+            ACRA.init(this);
+            ACRA.getErrorReporter().putCustomData("installSource", installSource);
+        }
+    }
+
     public static Application get() {
         return weakSelf.get();
     }
@@ -54,39 +127,26 @@ public class Application extends android.app.Application {
 
     public static Backend getBackend() {
         final Application app = get();
-        synchronized (app) {
+        synchronized (app.futureBackend) {
             if (app.backend == null) {
+                Backend backend = null;
                 if (new File("/sys/module/wireguard").exists()) {
                     try {
                         app.rootShell.start();
-                        app.backend = new WgQuickBackend(app.getApplicationContext());
-                    } catch (final Exception ignored) { }
-                }
-                if (app.backend == null)
-                    app.backend = new GoBackend(app.getApplicationContext());
-                synchronized (app.haveBackendCallbacksLock) {
-                    for (final BackendCallback callback : app.haveBackendCallbacks)
-                        app.handler.post(() -> callback.callback(app.backend));
-                    app.haveBackendCallbacks = null;
+                        backend = new WgQuickBackend(app.getApplicationContext());
+                    } catch (final Exception ignored) {
+                    }
                 }
+                if (backend == null)
+                    backend = new GoBackend(app.getApplicationContext());
+                app.backend = backend;
             }
             return app.backend;
         }
     }
 
-    @FunctionalInterface
-    public interface BackendCallback {
-        void callback(final Backend backend);
-    }
-
-    public static void onHaveBackend(final BackendCallback callback) {
-        final Application app = get();
-        synchronized (app.haveBackendCallbacksLock) {
-            if (app.haveBackendCallbacks == null)
-                callback.callback(app.backend);
-            else
-                app.haveBackendCallbacks.add(callback);
-        }
+    public static CompletableFuture<Backend> getBackendAsync() {
+        return get().futureBackend;
     }
 
     public static RootShell getRootShell() {
@@ -109,11 +169,7 @@ public class Application extends android.app.Application {
     public void onCreate() {
         super.onCreate();
 
-        handler = new Handler(Looper.getMainLooper());
-        final Executor executor = AsyncTask.SERIAL_EXECUTOR;
-        final ConfigStore configStore = new FileConfigStore(getApplicationContext());
-
-        asyncWorker = new AsyncWorker(executor, handler);
+        asyncWorker = new AsyncWorker(AsyncTask.SERIAL_EXECUTOR, new Handler(Looper.getMainLooper()));
         rootShell = new RootShell(getApplicationContext());
         toolsInstaller = new ToolsInstaller(getApplicationContext());
 
@@ -122,8 +178,16 @@ public class Application extends android.app.Application {
                 sharedPreferences.getBoolean("dark_theme", false) ?
                         AppCompatDelegate.MODE_NIGHT_YES : AppCompatDelegate.MODE_NIGHT_NO);
 
-        tunnelManager = new TunnelManager(configStore);
-        asyncWorker.runAsync(Application::getBackend);
+        tunnelManager = new TunnelManager(new FileConfigStore(getApplicationContext()));
         tunnelManager.onCreate();
+
+        asyncWorker.supplyAsync(Application::getBackend).thenAccept(backend -> {
+            futureBackend.complete(backend);
+            if (ACRA.isInitialised()) {
+                ACRA.getErrorReporter().putCustomData("backend", backend.getClass().getSimpleName());
+                asyncWorker.supplyAsync(backend::getVersion).thenAccept(version ->
+                        ACRA.getErrorReporter().putCustomData("backendVersion", version));
+            }
+        });
     }
 }

app/src/main/java/com/wireguard/android/BootShutdownReceiver.java

@@ -20,7 +20,7 @@ public class BootShutdownReceiver extends BroadcastReceiver {
 
     @Override
     public void onReceive(final Context context, final Intent intent) {
-        Application.onHaveBackend(backend -> {
+        Application.getBackendAsync().thenAccept(backend -> {
             if (!(backend instanceof WgQuickBackend))
                 return;
             final String action = intent.getAction();

app/src/main/java/com/wireguard/android/QuickTileService.java

@@ -12,12 +12,12 @@ import android.databinding.Observable;
 import android.databinding.Observable.OnPropertyChangedCallback;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
-import android.graphics.drawable.BitmapDrawable;
-import android.graphics.drawable.Drawable;
 import android.graphics.drawable.Icon;
 import android.os.Build;
+import android.os.IBinder;
 import android.service.quicksettings.Tile;
 import android.service.quicksettings.TileService;
+import android.support.annotation.Nullable;
 import android.util.Log;
 import android.widget.Toast;
 
@@ -41,14 +41,30 @@ public class QuickTileService extends TileService {
 
     private final OnStateChangedCallback onStateChangedCallback = new OnStateChangedCallback();
     private final OnTunnelChangedCallback onTunnelChangedCallback = new OnTunnelChangedCallback();
-    private Tunnel tunnel;
-    private Icon iconOn;
-    private Icon iconOff;
+    @Nullable private Tunnel tunnel;
+    @Nullable private Icon iconOn;
+    @Nullable private Icon iconOff;
+
+    /* This works around an annoying unsolved frameworks bug some people are hitting. */
+    @Override
+    @Nullable
+    public IBinder onBind(final Intent intent) {
+        IBinder ret = null;
+        try {
+            ret = super.onBind(intent);
+        } catch (final Exception e) {
+            Log.d(TAG, "Failed to bind to TileService", e);
+        }
+        return ret;
+    }
 
-    @SuppressWarnings("deprecation")
     @Override
     public void onCreate() {
-        final SlashDrawable icon = new SlashDrawable(getResources().getDrawable(R.drawable.ic_tile));
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+            iconOff = iconOn = Icon.createWithResource(this, R.drawable.ic_tile);
+            return;
+        }
+        final SlashDrawable icon = new SlashDrawable(getResources().getDrawable(R.drawable.ic_tile, Application.get().getTheme()));
         icon.setAnimationEnabled(false); /* Unfortunately we can't have animations, since Icons are marshaled. */
         icon.setSlashed(false);
         Bitmap b = Bitmap.createBitmap(icon.getIntrinsicWidth(), icon.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
@@ -67,6 +83,11 @@ public class QuickTileService extends TileService {
     @Override
     public void onClick() {
         if (tunnel != null) {
+            final Tile tile = getQsTile();
+            if (tile != null) {
+                tile.setIcon(tile.getIcon() == iconOn ? iconOff : iconOn);
+                tile.updateTile();
+            }
             tunnel.setState(State.TOGGLE).whenComplete(this::onToggleFinished);
         } else {
             final Intent intent = new Intent(this, MainActivity.class);
@@ -91,7 +112,7 @@ public class QuickTileService extends TileService {
     }
 
     private void onToggleFinished(@SuppressWarnings("unused") final State state,
-                                  final Throwable throwable) {
+                                  @Nullable final Throwable throwable) {
         if (throwable == null)
             return;
         final String error = ExceptionLoggers.unwrapMessage(throwable);

app/src/main/java/com/wireguard/android/activity/BaseActivity.java

@@ -9,10 +9,10 @@ package com.wireguard.android.activity;
 import android.databinding.CallbackRegistry;
 import android.databinding.CallbackRegistry.NotifierCallback;
 import android.os.Bundle;
+import android.support.annotation.Nullable;
 
 import com.wireguard.android.Application;
 import com.wireguard.android.model.Tunnel;
-import com.wireguard.android.model.TunnelManager;
 
 import java.util.Objects;
 
@@ -24,29 +24,31 @@ public abstract class BaseActivity extends ThemeChangeAwareActivity {
     private static final String KEY_SELECTED_TUNNEL = "selected_tunnel";
 
     private final SelectionChangeRegistry selectionChangeRegistry = new SelectionChangeRegistry();
-    private Tunnel selectedTunnel;
+    @Nullable private Tunnel selectedTunnel;
 
-    public void addOnSelectedTunnelChangedListener(
-            final OnSelectedTunnelChangedListener listener) {
+    public void addOnSelectedTunnelChangedListener(final OnSelectedTunnelChangedListener listener) {
         selectionChangeRegistry.add(listener);
     }
 
+    @Nullable
     public Tunnel getSelectedTunnel() {
         return selectedTunnel;
     }
 
     @Override
-    protected void onCreate(final Bundle savedInstanceState) {
+    protected void onCreate(@Nullable final Bundle savedInstanceState) {
         // Restore the saved tunnel if there is one; otherwise grab it from the arguments.
-        String savedTunnelName = null;
+        final String savedTunnelName;
         if (savedInstanceState != null)
             savedTunnelName = savedInstanceState.getString(KEY_SELECTED_TUNNEL);
         else if (getIntent() != null)
             savedTunnelName = getIntent().getStringExtra(KEY_SELECTED_TUNNEL);
-        if (savedTunnelName != null) {
-            final TunnelManager tunnelManager = Application.getTunnelManager();
-            selectedTunnel = tunnelManager.getTunnels().get(savedTunnelName);
-        }
+        else
+            savedTunnelName = null;
+
+        if (savedTunnelName != null)
+            Application.getTunnelManager().getTunnels()
+                    .thenAccept(tunnels -> setSelectedTunnel(tunnels.get(savedTunnelName)));
 
         // The selected tunnel must be set before the superclass method recreates fragments.
         super.onCreate(savedInstanceState);
@@ -59,14 +61,14 @@ public abstract class BaseActivity extends ThemeChangeAwareActivity {
         super.onSaveInstanceState(outState);
     }
 
-    protected abstract void onSelectedTunnelChanged(Tunnel oldTunnel, Tunnel newTunnel);
+    protected abstract void onSelectedTunnelChanged(@Nullable Tunnel oldTunnel, @Nullable Tunnel newTunnel);
 
     public void removeOnSelectedTunnelChangedListener(
             final OnSelectedTunnelChangedListener listener) {
         selectionChangeRegistry.remove(listener);
     }
 
-    public void setSelectedTunnel(final Tunnel tunnel) {
+    public void setSelectedTunnel(@Nullable final Tunnel tunnel) {
         final Tunnel oldTunnel = selectedTunnel;
         if (Objects.equals(oldTunnel, tunnel))
             return;
@@ -76,7 +78,7 @@ public abstract class BaseActivity extends ThemeChangeAwareActivity {
     }
 
     public interface OnSelectedTunnelChangedListener {
-        void onSelectedTunnelChanged(Tunnel oldTunnel, Tunnel newTunnel);
+        void onSelectedTunnelChanged(@Nullable Tunnel oldTunnel, @Nullable Tunnel newTunnel);
     }
 
     private static final class SelectionChangeNotifier

app/src/main/java/com/wireguard/android/activity/MainActivity.java

@@ -9,12 +9,14 @@ package com.wireguard.android.activity;
 import android.annotation.SuppressLint;
 import android.content.Intent;
 import android.os.Bundle;
-import android.support.v4.app.Fragment;
+import android.support.annotation.Nullable;
 import android.support.v4.app.FragmentManager;
 import android.support.v4.app.FragmentTransaction;
-import android.util.Log;
+import android.support.v7.app.ActionBar;
 import android.view.Menu;
 import android.view.MenuItem;
+import android.view.View;
+import android.widget.LinearLayout;
 
 import com.wireguard.android.R;
 import com.wireguard.android.fragment.TunnelDetailFragment;
@@ -22,89 +24,63 @@ import com.wireguard.android.fragment.TunnelEditorFragment;
 import com.wireguard.android.fragment.TunnelListFragment;
 import com.wireguard.android.model.Tunnel;
 
-import java9.util.stream.Stream;
-
 /**
  * CRUD interface for WireGuard tunnels. This activity serves as the main entry point to the
  * WireGuard application, and contains several fragments for listing, viewing details of, and
  * editing the configuration and interface state of WireGuard tunnels.
  */
 
-public class MainActivity extends BaseActivity {
-    private static final String KEY_STATE = "fragment_state";
-    private static final String TAG = "WireGuard/" + MainActivity.class.getSimpleName();
-    private State state = State.EMPTY;
-
-    private boolean moveToState(final State nextState) {
-        if (state == nextState)
-            return false;
-        final FragmentManager fragmentManager = getSupportFragmentManager();
-        Log.i(TAG, "Moving from " + state.name() + " to " + nextState.name());
-        if (nextState.layer > state.layer + 1) {
-            moveToState(State.ofLayer(state.layer + 1));
-            moveToState(nextState);
-            return true;
-        } else if (nextState.layer == state.layer + 1) {
-            final Fragment fragment = Fragment.instantiate(this, nextState.fragment);
-            final FragmentTransaction transaction = fragmentManager.beginTransaction()
-                    .replace(R.id.master_fragment, fragment)
-                    .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
-            if (state.layer > 0)
-                transaction.addToBackStack(null);
-            transaction.commit();
-        } else if (nextState.layer == state.layer - 1) {
-            if (fragmentManager.getBackStackEntryCount() == 0)
-                return false;
-            fragmentManager.popBackStack();
-        } else if (nextState.layer < state.layer - 1) {
-            moveToState(State.ofLayer(state.layer - 1));
-            moveToState(nextState);
-            return true;
-        }
-        state = nextState;
-        if (state.layer <= State.LIST.layer)
-            setSelectedTunnel(null);
-        updateActionBar();
-        return true;
-    }
+public class MainActivity extends BaseActivity
+        implements FragmentManager.OnBackStackChangedListener {
+    @Nullable private ActionBar actionBar;
+    private boolean isTwoPaneLayout;
+    @Nullable private TunnelListFragment listFragment;
 
     @Override
     public void onBackPressed() {
-        TunnelListFragment fragment = null;
-        try {
-            fragment = ((TunnelListFragment) getSupportFragmentManager().getFragments().get(0));
-        } catch (final ClassCastException ignored) { }
-        if (fragment == null || !fragment.collapseActionMenu()) {
-            if (!moveToState(State.ofLayer(state.layer - 1)))
-                super.onBackPressed();
+        final int backStackEntries = getSupportFragmentManager().getBackStackEntryCount();
+        // If the action menu is visible and expanded, collapse it instead of navigating back.
+        if (isTwoPaneLayout || backStackEntries == 0) {
+            if (listFragment != null && listFragment.collapseActionMenu())
+                return;
         }
+        // If the two-pane layout does not have an editor open, going back should exit the app.
+        if (isTwoPaneLayout && backStackEntries <= 1) {
+            finish();
+            return;
+        }
+        // Deselect the current tunnel on navigating back from the detail pane to the one-pane list.
+        if (!isTwoPaneLayout && backStackEntries == 1) {
+            setSelectedTunnel(null);
+            return;
+        }
+        super.onBackPressed();
+    }
+
+    @Override public void onBackStackChanged() {
+        if (actionBar == null)
+            return;
+        // Do not show the home menu when the two-pane layout is at the detail view (see above).
+        final int backStackEntries = getSupportFragmentManager().getBackStackEntryCount();
+        final int minBackStackEntries = isTwoPaneLayout ? 2 : 1;
+        actionBar.setDisplayHomeAsUpEnabled(backStackEntries >= minBackStackEntries);
     }
 
     // We use onTouchListener here to avoid the UI click sound, hence
     // calling View#performClick defeats the purpose of it.
     @SuppressLint("ClickableViewAccessibility")
     @Override
-    protected void onCreate(final Bundle savedInstanceState) {
+    protected void onCreate(@Nullable final Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main_activity);
-        if (savedInstanceState != null && savedInstanceState.getString(KEY_STATE) != null)
-            state = State.valueOf(savedInstanceState.getString(KEY_STATE));
-        if (state == State.EMPTY) {
-            State initialState = getSelectedTunnel() != null ? State.DETAIL : State.LIST;
-            if (getIntent() != null && getIntent().getStringExtra(KEY_STATE) != null)
-                initialState = State.valueOf(getIntent().getStringExtra(KEY_STATE));
-            moveToState(initialState);
-        }
-        updateActionBar();
-        final int actionBarId = getResources().getIdentifier("action_bar", "id", getPackageName());
-        if (actionBarId != 0 && findViewById(actionBarId) != null) {
-            findViewById(actionBarId).setOnTouchListener((v, e) -> {
-                try {
-                    ((TunnelListFragment) getSupportFragmentManager().getFragments().get(0)).collapseActionMenu();
-                } catch (final ClassCastException ignored) { }
-                return false;
-            });
-        }
+        actionBar = getSupportActionBar();
+        isTwoPaneLayout = findViewById(R.id.master_detail_wrapper) instanceof LinearLayout;
+        listFragment = (TunnelListFragment) getSupportFragmentManager().findFragmentByTag("LIST");
+        getSupportFragmentManager().addOnBackStackChangedListener(this);
+        onBackStackChanged();
+        final View actionBarView = findViewById(R.id.action_bar);
+        if (actionBarView != null)
+            actionBarView.setOnTouchListener((v, e) -> listFragment != null && listFragment.collapseActionMenu());
     }
 
     @Override
@@ -118,11 +94,14 @@ public class MainActivity extends BaseActivity {
         switch (item.getItemId()) {
             case android.R.id.home:
                 // The back arrow in the action bar should act the same as the back button.
-                moveToState(State.ofLayer(state.layer - 1));
+                onBackPressed();
                 return true;
             case R.id.menu_action_edit:
-                if (getSelectedTunnel() != null)
-                    moveToState(State.EDITOR);
+                getSupportFragmentManager().beginTransaction()
+                        .replace(R.id.detail_container, new TunnelEditorFragment())
+                        .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
+                        .addToBackStack(null)
+                        .commit();
                 return true;
             case R.id.menu_action_save:
                 // This menu item is handled by the editor fragment.
@@ -136,37 +115,26 @@ public class MainActivity extends BaseActivity {
     }
 
     @Override
-    protected void onSaveInstanceState(final Bundle outState) {
-        outState.putString(KEY_STATE, state.name());
-        super.onSaveInstanceState(outState);
-    }
-
-    @Override
-    protected void onSelectedTunnelChanged(final Tunnel oldTunnel, final Tunnel newTunnel) {
-        moveToState(newTunnel != null ? State.DETAIL : State.LIST);
-    }
-
-    private void updateActionBar() {
-        if (getSupportActionBar() != null)
-            getSupportActionBar().setDisplayHomeAsUpEnabled(state.layer > State.LIST.layer);
-    }
-
-    private enum State {
-        EMPTY(null, 0),
-        LIST(TunnelListFragment.class, 1),
-        DETAIL(TunnelDetailFragment.class, 2),
-        EDITOR(TunnelEditorFragment.class, 3);
-
-        private final String fragment;
-        private final int layer;
-
-        State(final Class<? extends Fragment> fragment, final int layer) {
-            this.fragment = fragment != null ? fragment.getName() : null;
-            this.layer = layer;
+    protected void onSelectedTunnelChanged(@Nullable final Tunnel oldTunnel,
+                                           @Nullable final Tunnel newTunnel) {
+        final FragmentManager fragmentManager = getSupportFragmentManager();
+        final int backStackEntries = fragmentManager.getBackStackEntryCount();
+        if (newTunnel == null) {
+            // Clear everything off the back stack (all editors and detail fragments).
+            fragmentManager.popBackStackImmediate(0, FragmentManager.POP_BACK_STACK_INCLUSIVE);
+            return;
         }
-
-        private static State ofLayer(final int layer) {
-            return Stream.of(State.values()).filter(s -> s.layer == layer).findFirst().get();
+        if (backStackEntries == 2) {
+            // Pop the editor off the back stack to reveal the detail fragment. Use the immediate
+            // method to avoid the editor picking up the new tunnel while it is still visible.
+            fragmentManager.popBackStackImmediate();
+        } else if (backStackEntries == 0) {
+            // Create and show a new detail fragment.
+            fragmentManager.beginTransaction()
+                    .add(R.id.detail_container, new TunnelDetailFragment())
+                    .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
+                    .addToBackStack(null)
+                    .commit();
         }
     }
 }

app/src/main/java/com/wireguard/android/activity/SettingsActivity.java

@@ -8,12 +8,13 @@ package com.wireguard.android.activity;
 
 import android.content.pm.PackageManager;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.support.v4.app.ActivityCompat;
 import android.support.v4.content.ContextCompat;
 import android.support.v7.preference.Preference;
 import android.support.v7.preference.PreferenceFragmentCompat;
 import android.support.v7.preference.PreferenceScreen;
+import android.util.SparseArray;
 import android.view.MenuItem;
 
 import com.wireguard.android.Application;
@@ -22,16 +23,14 @@ import com.wireguard.android.backend.WgQuickBackend;
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
 
 /**
  * Interface for changing application-global persistent settings.
  */
 
 public class SettingsActivity extends ThemeChangeAwareActivity {
-    private final Map<Integer, PermissionRequestCallback> permissionRequestCallbacks = new HashMap<>();
+    private final SparseArray<PermissionRequestCallback> permissionRequestCallbacks = new SparseArray<>();
     private int permissionRequestCounter;
 
     public void ensurePermissions(final String[] permissions, final PermissionRequestCallback cb) {
@@ -54,7 +53,7 @@ public class SettingsActivity extends ThemeChangeAwareActivity {
     }
 
     @Override
-    protected void onCreate(final Bundle savedInstanceState) {
+    protected void onCreate(@Nullable final Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         if (getSupportFragmentManager().findFragmentById(android.R.id.content) == null) {
             getSupportFragmentManager().beginTransaction()
@@ -76,8 +75,8 @@ public class SettingsActivity extends ThemeChangeAwareActivity {
 
     @Override
     public void onRequestPermissionsResult(final int requestCode,
-                                           @NonNull final String[] permissions,
-                                           @NonNull final int[] grantResults) {
+                                           final String[] permissions,
+                                           final int[] grantResults) {
         final PermissionRequestCallback f = permissionRequestCallbacks.get(requestCode);
         if (f != null) {
             permissionRequestCallbacks.remove(requestCode);
@@ -100,7 +99,7 @@ public class SettingsActivity extends ThemeChangeAwareActivity {
             for (final Preference pref : wgQuickOnlyPrefs)
                 pref.setVisible(false);
             final PreferenceScreen screen = getPreferenceScreen();
-            Application.onHaveBackend(backend -> {
+            Application.getBackendAsync().thenAccept(backend -> {
                 for (final Preference pref : wgQuickOnlyPrefs) {
                     if (backend instanceof WgQuickBackend)
                         pref.setVisible(true);

app/src/main/java/com/wireguard/android/activity/ThemeChangeAwareActivity.java

@@ -8,6 +8,7 @@ package com.wireguard.android.activity;
 import android.content.SharedPreferences;
 import android.content.res.Resources;
 import android.os.Bundle;
+import android.support.annotation.Nullable;
 import android.support.v7.app.AppCompatActivity;
 import android.support.v7.app.AppCompatDelegate;
 import android.util.Log;
@@ -19,7 +20,7 @@ import java.lang.reflect.Field;
 public abstract class ThemeChangeAwareActivity extends AppCompatActivity implements SharedPreferences.OnSharedPreferenceChangeListener {
     private static final String TAG = "WireGuard/" + ThemeChangeAwareActivity.class.getSimpleName();
 
-    private static Resources lastResources;
+    @Nullable private static Resources lastResources;
     private static boolean lastDarkMode;
     private static synchronized void invalidateDrawableCache(final Resources resources, final boolean darkMode) {
         if (resources == lastResources && darkMode == lastDarkMode)
@@ -51,7 +52,7 @@ public abstract class ThemeChangeAwareActivity extends AppCompatActivity impleme
 
 
     @Override
-    protected void onCreate(final Bundle savedInstanceState) {
+    protected void onCreate(@Nullable final Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         Application.getSharedPreferences().registerOnSharedPreferenceChangeListener(this);
     }

app/src/main/java/com/wireguard/android/activity/TunnelCreatorActivity.java

@@ -7,6 +7,7 @@
 package com.wireguard.android.activity;
 
 import android.os.Bundle;
+import android.support.annotation.Nullable;
 
 import com.wireguard.android.fragment.TunnelEditorFragment;
 import com.wireguard.android.model.Tunnel;
@@ -18,7 +19,7 @@ import com.wireguard.android.model.Tunnel;
 public class TunnelCreatorActivity extends BaseActivity {
     @Override
     @SuppressWarnings("UnnecessaryFullyQualifiedName")
-    protected void onCreate(final Bundle savedInstanceState) {
+    protected void onCreate(@Nullable final Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         if (getSupportFragmentManager().findFragmentById(android.R.id.content) == null) {
             getSupportFragmentManager().beginTransaction()
@@ -28,7 +29,7 @@ public class TunnelCreatorActivity extends BaseActivity {
     }
 
     @Override
-    protected void onSelectedTunnelChanged(final Tunnel oldTunnel, final Tunnel newTunnel) {
+    protected void onSelectedTunnelChanged(@Nullable final Tunnel oldTunnel, @Nullable final Tunnel newTunnel) {
         finish();
     }
 }

app/src/main/java/com/wireguard/android/backend/GoBackend.java

@@ -10,6 +10,7 @@ import android.app.PendingIntent;
 import android.content.Context;
 import android.content.Intent;
 import android.os.ParcelFileDescriptor;
+import android.support.annotation.Nullable;
 import android.support.v4.util.ArraySet;
 import android.util.Log;
 
@@ -29,6 +30,7 @@ import com.wireguard.crypto.KeyEncoding;
 import java.net.InetAddress;
 import java.util.Collections;
 import java.util.Formatter;
+import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
@@ -40,7 +42,7 @@ public final class GoBackend implements Backend {
     private static CompletableFuture<VpnService> vpnService = new CompletableFuture<>();
 
     private final Context context;
-    private Tunnel currentTunnel;
+    @Nullable private Tunnel currentTunnel;
     private int currentTunnelHandle = -1;
 
     public GoBackend(final Context context) {
@@ -114,12 +116,14 @@ public final class GoBackend implements Backend {
         return getState(tunnel);
     }
 
-    private void setStateInternal(final Tunnel tunnel, final Config config, final State state)
+    private void setStateInternal(final Tunnel tunnel, @Nullable final Config config, final State state)
             throws Exception {
 
         if (state == State.UP) {
             Log.i(TAG, "Bringing tunnel up");
 
+            Objects.requireNonNull(config, "Trying to bring up a tunnel with no config");
+
             if (VpnService.prepare(context) != null)
                 throw new Exception("VPN service not authorized by user");
 
@@ -236,16 +240,19 @@ public final class GoBackend implements Backend {
 
         @Override
         public void onDestroy() {
-            for (final Tunnel tunnel : Application.getTunnelManager().getTunnels()) {
-                if (tunnel != null && tunnel.getState() != State.DOWN)
-                    tunnel.setState(State.DOWN);
-            }
+            Application.getTunnelManager().getTunnels().thenAccept(tunnels -> {
+                for (final Tunnel tunnel : tunnels) {
+                    if (tunnel != null && tunnel.getState() != State.DOWN)
+                        tunnel.setState(State.DOWN);
+                }
+            });
+
             vpnService = vpnService.newIncompleteFuture();
             super.onDestroy();
         }
 
         @Override
-        public int onStartCommand(final Intent intent, final int flags, final int startId) {
+        public int onStartCommand(@Nullable final Intent intent, final int flags, final int startId) {
             vpnService.complete(this);
             if (intent == null || intent.getComponent() == null || !intent.getComponent().getPackageName().equals(getPackageName())) {
                 Log.d(TAG, "Service started by Always-on VPN feature");

app/src/main/java/com/wireguard/android/backend/WgQuickBackend.java

@@ -7,6 +7,7 @@
 package com.wireguard.android.backend;
 
 import android.content.Context;
+import android.support.annotation.Nullable;
 import android.util.Log;
 
 import com.wireguard.android.Application;
@@ -21,6 +22,7 @@ import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 import java.util.Set;
 
 import java9.util.stream.Collectors;
@@ -106,8 +108,9 @@ public final class WgQuickBackend implements Backend {
         return getState(tunnel);
     }
 
-    private void setStateInternal(final Tunnel tunnel, final Config config, final State state)
-            throws Exception {
+    private void setStateInternal(final Tunnel tunnel, @Nullable final Config config, final State state) throws Exception {
+        Objects.requireNonNull(config, "Trying to set state with a null config");
+
         final File tempFile = new File(localTemporaryDir, tunnel.getName() + ".conf");
         try (final FileOutputStream stream = new FileOutputStream(tempFile, false)) {
             stream.write(config.toString().getBytes(StandardCharsets.UTF_8));

app/src/main/java/com/wireguard/android/databinding/ItemChangeListener.java

@@ -9,6 +9,7 @@ package com.wireguard.android.databinding;
 import android.databinding.DataBindingUtil;
 import android.databinding.ObservableList;
 import android.databinding.ViewDataBinding;
+import android.support.annotation.Nullable;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -16,6 +17,7 @@ import android.view.ViewGroup;
 import com.wireguard.android.BR;
 
 import java.lang.ref.WeakReference;
+import java.util.Objects;
 
 /**
  * Helper class for binding an ObservableList to the children of a ViewGroup.
@@ -26,7 +28,7 @@ class ItemChangeListener<T> {
     private final ViewGroup container;
     private final int layoutId;
     private final LayoutInflater layoutInflater;
-    private ObservableList<T> list;
+    @Nullable private ObservableList<T> list;
 
     ItemChangeListener(final ViewGroup container, final int layoutId) {
         this.container = container;
@@ -34,17 +36,21 @@ class ItemChangeListener<T> {
         layoutInflater = LayoutInflater.from(container.getContext());
     }
 
-    private View getView(final int position, final View convertView) {
-        ViewDataBinding binding = DataBindingUtil.getBinding(convertView);
-        if (binding == null)
+    private View getView(final int position, @Nullable final View convertView) {
+        ViewDataBinding binding = convertView != null ? DataBindingUtil.getBinding(convertView) : null;
+        if (binding == null) {
             binding = DataBindingUtil.inflate(layoutInflater, layoutId, container, false);
+        }
+
+        Objects.requireNonNull(list, "Trying to get a view while list is still null");
+
         binding.setVariable(BR.collection, list);
         binding.setVariable(BR.item, list.get(position));
         binding.executePendingBindings();
         return binding.getRoot();
     }
 
-    void setList(final ObservableList<T> newList) {
+    void setList(@Nullable final ObservableList<T> newList) {
         if (list != null)
             list.removeOnListChangedCallback(callback);
         list = newList;

app/src/main/java/com/wireguard/android/databinding/ObservableKeyedRecyclerViewAdapter.java

@@ -10,7 +10,7 @@ import android.content.Context;
 import android.databinding.DataBindingUtil;
 import android.databinding.ObservableList;
 import android.databinding.ViewDataBinding;
-import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.support.v7.widget.RecyclerView;
 import android.support.v7.widget.RecyclerView.Adapter;
 import android.view.LayoutInflater;
@@ -31,8 +31,8 @@ public class ObservableKeyedRecyclerViewAdapter<K, E extends Keyed<? extends K>>
     private final OnListChangedCallback<E> callback = new OnListChangedCallback<>(this);
     private final int layoutId;
     private final LayoutInflater layoutInflater;
-    private ObservableKeyedList<K, E> list;
-    private RowConfigurationHandler rowConfigurationHandler;
+    @Nullable private ObservableKeyedList<K, E> list;
+    @Nullable private RowConfigurationHandler rowConfigurationHandler;
 
     ObservableKeyedRecyclerViewAdapter(final Context context, final int layoutId,
                                        final ObservableKeyedList<K, E> list) {
@@ -46,6 +46,7 @@ public class ObservableKeyedRecyclerViewAdapter<K, E extends Keyed<? extends K>>
         return list != null ? list.size() : 0;
     }
 
+    @Nullable
     private E getItem(final int position) {
         if (list == null || position < 0 || position >= list.size())
             return null;
@@ -58,30 +59,34 @@ public class ObservableKeyedRecyclerViewAdapter<K, E extends Keyed<? extends K>>
         return key != null ? key.hashCode() : -1;
     }
 
+    @Nullable
     private K getKey(final int position) {
         final E item = getItem(position);
         return item != null ? item.getKey() : null;
     }
 
-    @NonNull @Override
-    public ViewHolder onCreateViewHolder(@NonNull final ViewGroup parent, final int viewType) {
+    @Override
+    public ViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) {
         return new ViewHolder(DataBindingUtil.inflate(layoutInflater, layoutId, parent, false));
     }
 
     @SuppressWarnings("unchecked")
     @Override
-    public void onBindViewHolder(@NonNull final ViewHolder holder, final int position) {
+    public void onBindViewHolder(final ViewHolder holder, final int position) {
         holder.binding.setVariable(BR.collection, list);
         holder.binding.setVariable(BR.key, getKey(position));
         holder.binding.setVariable(BR.item, getItem(position));
         holder.binding.executePendingBindings();
 
         if (rowConfigurationHandler != null) {
-            rowConfigurationHandler.onConfigureRow(holder.binding, getItem(position), position);
+            E item = getItem(position);
+            if (item != null) {
+                rowConfigurationHandler.onConfigureRow(holder.binding, item, position);
+            }
         }
     }
 
-    void setList(final ObservableKeyedList<K, E> newList) {
+    void setList(@Nullable final ObservableKeyedList<K, E> newList) {
         if (list != null)
             list.removeOnListChangedCallback(callback);
         list = newList;

app/src/main/java/com/wireguard/android/fragment/AppListDialogFragment.java

@@ -8,7 +8,6 @@ package com.wireguard.android.fragment;
 
 import android.app.Activity;
 import android.app.Dialog;
-import android.content.Context;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.pm.PackageManager;
@@ -22,10 +21,8 @@ import android.widget.Toast;
 
 import com.wireguard.android.Application;
 import com.wireguard.android.R;
-import com.wireguard.android.activity.BaseActivity;
 import com.wireguard.android.databinding.AppListDialogFragmentBinding;
 import com.wireguard.android.model.ApplicationData;
-import com.wireguard.android.model.Tunnel;
 import com.wireguard.android.util.ExceptionLoggers;
 import com.wireguard.android.util.ObservableKeyedArrayList;
 import com.wireguard.android.util.ObservableKeyedList;
@@ -58,17 +55,12 @@ public class AppListDialogFragment extends DialogFragment {
         currentlyExcludedApps = Arrays.asList(getArguments().getStringArray(KEY_EXCLUDED_APPS));
     }
 
-    @Override
-    public void onAttach(final Context context) {
-        super.onAttach(context);
-    }
-
     @Override
     public Dialog onCreateDialog(final Bundle savedInstanceState) {
         final AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(getActivity());
         alertDialogBuilder.setTitle(R.string.excluded_applications);
 
-        AppListDialogFragmentBinding binding = AppListDialogFragmentBinding.inflate(getActivity().getLayoutInflater(), null, false);
+        final AppListDialogFragmentBinding binding = AppListDialogFragmentBinding.inflate(getActivity().getLayoutInflater(), null, false);
         binding.executePendingBindings();
         alertDialogBuilder.setView(binding.getRoot());
 

app/src/main/java/com/wireguard/android/fragment/BaseFragment.java

@@ -10,7 +10,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.databinding.DataBindingUtil;
 import android.databinding.ViewDataBinding;
-import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.support.design.widget.Snackbar;
 import android.support.v4.app.Fragment;
 import android.util.Log;
@@ -37,10 +37,11 @@ public abstract class BaseFragment extends Fragment implements OnSelectedTunnelC
     private static final String TAG = "WireGuard/" + BaseFragment.class.getSimpleName();
     private static final int REQUEST_CODE_VPN_PERMISSION = 23491;
 
-    private BaseActivity activity;
-    private Tunnel pendingTunnel;
-    private Boolean pendingTunnelUp;
+    @Nullable private BaseActivity activity;
+    @Nullable private Tunnel pendingTunnel;
+    @Nullable private Boolean pendingTunnelUp;
 
+    @Nullable
     protected Tunnel getSelectedTunnel() {
         return activity != null ? activity.getSelectedTunnel() : null;
     }
@@ -65,7 +66,7 @@ public abstract class BaseFragment extends Fragment implements OnSelectedTunnelC
     }
 
     @Override
-    public void onActivityResult(int requestCode, int resultCode, Intent data) {
+    public void onActivityResult(final int requestCode, final int resultCode, @Nullable final Intent data) {
         super.onActivityResult(requestCode, resultCode, data);
 
         if (requestCode == REQUEST_CODE_VPN_PERMISSION) {
@@ -76,7 +77,7 @@ public abstract class BaseFragment extends Fragment implements OnSelectedTunnelC
         }
     }
 
-    protected void setSelectedTunnel(final Tunnel tunnel) {
+    protected void setSelectedTunnel(@Nullable final Tunnel tunnel) {
         if (activity != null)
             activity.setSelectedTunnel(tunnel);
     }
@@ -90,8 +91,10 @@ public abstract class BaseFragment extends Fragment implements OnSelectedTunnelC
             tunnel = ((TunnelListItemBinding) binding).getItem();
         else
             return;
+        if (tunnel == null)
+            return;
 
-        Application.onHaveBackend(backend -> {
+        Application.getBackendAsync().thenAccept(backend -> {
             if (backend instanceof GoBackend) {
                 final Intent intent = GoBackend.VpnService.prepare(view.getContext());
                 if (intent != null) {
@@ -106,7 +109,7 @@ public abstract class BaseFragment extends Fragment implements OnSelectedTunnelC
         });
     }
 
-    private void setTunnelStateWithPermissionsResult(@NonNull final Tunnel tunnel, final boolean checked) {
+    private void setTunnelStateWithPermissionsResult(final Tunnel tunnel, final boolean checked) {
         tunnel.setState(State.of(checked)).whenComplete((state, throwable) -> {
             if (throwable == null)
                 return;

app/src/main/java/com/wireguard/android/fragment/ConfigNamingDialogFragment.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright © 2018 Eric Kuck <eric@bluelinelabs.com>.
+ * Copyright © 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.android.fragment;
+
+import android.app.Activity;
+import android.app.Dialog;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.os.Bundle;
+import android.support.annotation.Nullable;
+import android.support.v4.app.DialogFragment;
+import android.support.v7.app.AlertDialog;
+import android.view.WindowManager;
+import android.view.inputmethod.InputMethodManager;
+
+import com.wireguard.android.Application;
+import com.wireguard.android.R;
+import com.wireguard.android.databinding.ConfigNamingDialogFragmentBinding;
+import com.wireguard.config.Config;
+
+import java.io.IOException;
+import java.util.Objects;
+
+public class ConfigNamingDialogFragment extends DialogFragment {
+
+    private static final String KEY_CONFIG_TEXT = "config_text";
+
+    @Nullable private Config config;
+    @Nullable private ConfigNamingDialogFragmentBinding binding;
+    @Nullable private InputMethodManager imm;
+
+    public static ConfigNamingDialogFragment newInstance(final String configText) {
+        final Bundle extras = new Bundle();
+        extras.putString(KEY_CONFIG_TEXT, configText);
+        final ConfigNamingDialogFragment fragment = new ConfigNamingDialogFragment();
+        fragment.setArguments(extras);
+        return fragment;
+    }
+
+    @Override
+    public void onCreate(@Nullable final Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        try {
+            config = Config.from(getArguments().getString(KEY_CONFIG_TEXT));
+        } catch (final IOException exception) {
+            throw new RuntimeException("Invalid config passed to " + getClass().getSimpleName(), exception);
+        }
+    }
+
+    @Override public void onResume() {
+        super.onResume();
+
+        final AlertDialog dialog = (AlertDialog) getDialog();
+        if (dialog != null) {
+            dialog.getButton(DialogInterface.BUTTON_POSITIVE).setOnClickListener(v -> createTunnelAndDismiss());
+
+            setKeyboardVisible(true);
+        }
+    }
+
+    @Override
+    public Dialog onCreateDialog(final Bundle savedInstanceState) {
+        final Activity activity = getActivity();
+
+        imm = (InputMethodManager) getActivity().getSystemService(Context.INPUT_METHOD_SERVICE);
+
+        final AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(activity);
+        alertDialogBuilder.setTitle(R.string.import_from_qrcode);
+
+        binding = ConfigNamingDialogFragmentBinding.inflate(getActivity().getLayoutInflater(), null, false);
+        binding.executePendingBindings();
+        alertDialogBuilder.setView(binding.getRoot());
+
+        alertDialogBuilder.setPositiveButton(R.string.create_tunnel, null);
+        alertDialogBuilder.setNegativeButton(R.string.cancel, (dialog, which) -> dismiss());
+
+        return alertDialogBuilder.create();
+    }
+
+    @Override
+    public void dismiss() {
+        setKeyboardVisible(false);
+        super.dismiss();
+    }
+
+    private void createTunnelAndDismiss() {
+        if (binding != null) {
+            final String name = binding.tunnelNameText.getText().toString();
+
+            Application.getTunnelManager().create(name, config).whenComplete((tunnel, throwable) -> {
+                if (tunnel != null) {
+                    dismiss();
+                } else {
+                    binding.tunnelNameTextLayout.setError(throwable.getMessage());
+                }
+            });
+        }
+    }
+
+    private void setKeyboardVisible(final boolean visible) {
+        Objects.requireNonNull(imm);
+
+        if (visible) {
+            imm.toggleSoftInput(InputMethodManager.SHOW_FORCED, 0);
+        } else if (binding != null) {
+            imm.hideSoftInputFromWindow(binding.tunnelNameText.getWindowToken(), 0);
+        }
+    }
+
+}

app/src/main/java/com/wireguard/android/fragment/TunnelDetailFragment.java

@@ -7,7 +7,7 @@
 package com.wireguard.android.fragment;
 
 import android.os.Bundle;
-import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuInflater;
@@ -24,14 +24,16 @@ import com.wireguard.config.Config;
  */
 
 public class TunnelDetailFragment extends BaseFragment {
-    private TunnelDetailFragmentBinding binding;
+    @Nullable private TunnelDetailFragmentBinding binding;
 
     private void onConfigLoaded(final String name, final Config config) {
-        binding.setConfig(new Config.Observable(config, name));
+        if (binding != null) {
+            binding.setConfig(new Config.Observable(config, name));
+        }
     }
 
     @Override
-    public void onCreate(final Bundle savedInstanceState) {
+    public void onCreate(@Nullable final Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setHasOptionsMenu(true);
     }
@@ -42,8 +44,8 @@ public class TunnelDetailFragment extends BaseFragment {
     }
 
     @Override
-    public View onCreateView(@NonNull final LayoutInflater inflater, final ViewGroup container,
-                             final Bundle savedInstanceState) {
+    public View onCreateView(final LayoutInflater inflater, @Nullable final ViewGroup container,
+                             @Nullable final Bundle savedInstanceState) {
         super.onCreateView(inflater, container, savedInstanceState);
         binding = TunnelDetailFragmentBinding.inflate(inflater, container, false);
         binding.executePendingBindings();
@@ -57,7 +59,7 @@ public class TunnelDetailFragment extends BaseFragment {
     }
 
     @Override
-    public void onSelectedTunnelChanged(final Tunnel oldTunnel, final Tunnel newTunnel) {
+    public void onSelectedTunnelChanged(@Nullable final Tunnel oldTunnel, @Nullable final Tunnel newTunnel) {
         if (binding == null)
             return;
         binding.setTunnel(newTunnel);
@@ -68,7 +70,11 @@ public class TunnelDetailFragment extends BaseFragment {
     }
 
     @Override
-    public void onViewStateRestored(final Bundle savedInstanceState) {
+    public void onViewStateRestored(@Nullable final Bundle savedInstanceState) {
+        if (binding == null) {
+            return;
+        }
+
         binding.setFragment(this);
         onSelectedTunnelChanged(null, getSelectedTunnel());
         super.onViewStateRestored(savedInstanceState);

app/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java

@@ -11,7 +11,7 @@ import android.content.Context;
 import android.databinding.Observable;
 import android.databinding.ObservableList;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.support.design.widget.Snackbar;
 import android.support.v4.app.FragmentManager;
 import android.util.Log;
@@ -36,7 +36,10 @@ import com.wireguard.config.Attribute;
 import com.wireguard.config.Config;
 import com.wireguard.config.Peer;
 
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
+import java.util.Objects;
 
 /**
  * Fragment for editing a WireGuard configuration.
@@ -47,15 +50,17 @@ public class TunnelEditorFragment extends BaseFragment implements AppExclusionLi
     private static final String KEY_ORIGINAL_NAME = "original_name";
     private static final String TAG = "WireGuard/" + TunnelEditorFragment.class.getSimpleName();
 
-    private TunnelEditorFragmentBinding binding;
-    private Tunnel tunnel;
+    @Nullable private TunnelEditorFragmentBinding binding;
+    @Nullable private Tunnel tunnel;
 
     private void onConfigLoaded(final String name, final Config config) {
-        binding.setConfig(new Config.Observable(config, name));
+        if (binding != null) {
+            binding.setConfig(new Config.Observable(config, name));
+        }
     }
 
     private void onConfigSaved(final Tunnel savedTunnel,
-                               final Throwable throwable) {
+                               @Nullable final Throwable throwable) {
         final String message;
         if (throwable == null) {
             message = getString(R.string.config_save_success, savedTunnel.getName());
@@ -73,7 +78,7 @@ public class TunnelEditorFragment extends BaseFragment implements AppExclusionLi
     }
 
     @Override
-    public void onCreate(final Bundle savedInstanceState) {
+    public void onCreate(@Nullable final Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setHasOptionsMenu(true);
     }
@@ -93,24 +98,32 @@ public class TunnelEditorFragment extends BaseFragment implements AppExclusionLi
 
         @Override
         public void onItemRangeInserted(final ObservableList<Peer.Observable> sender, final int positionStart, final int itemCount) {
-            breakObjectOrientedLayeringHandler.onPropertyChanged(binding.getConfig(), BR.peers);
+            if (binding != null)
+                breakObjectOrientedLayeringHandler.onPropertyChanged(binding.getConfig(), BR.peers);
         }
         @Override
         public void onItemRangeRemoved(final ObservableList<Peer.Observable> sender, final int positionStart, final int itemCount) {
-            breakObjectOrientedLayeringHandler.onPropertyChanged(binding.getConfig(), BR.peers);
+            if (binding != null)
+                breakObjectOrientedLayeringHandler.onPropertyChanged(binding.getConfig(), BR.peers);
         }
     };
 
+    private final Collection<Object> breakObjectOrientedLayeringHandlerReceivers = new ArrayList<>();
     private final Observable.OnPropertyChangedCallback breakObjectOrientedLayeringHandler = new Observable.OnPropertyChangedCallback() {
         @Override
         public void onPropertyChanged(final Observable sender, final int propertyId) {
+            if (binding == null)
+                return;
             final Config.Observable config = binding.getConfig();
             if (config == null)
                 return;
             if (propertyId == BR.config) {
                 config.addOnPropertyChangedCallback(breakObjectOrientedLayeringHandler);
+                breakObjectOrientedLayeringHandlerReceivers.add(config);
                 config.getInterfaceSection().addOnPropertyChangedCallback(breakObjectOrientedLayeringHandler);
+                breakObjectOrientedLayeringHandlerReceivers.add(config.getInterfaceSection());
                 config.getPeers().addOnListChangedCallback(breakObjectListOrientedLayeringHandler);
+                breakObjectOrientedLayeringHandlerReceivers.add(config.getPeers());
             } else if (propertyId == BR.dnses || propertyId == BR.peers)
                 ;
             else
@@ -124,18 +137,26 @@ public class TunnelEditorFragment extends BaseFragment implements AppExclusionLi
     };
 
     @Override
-    public View onCreateView(@NonNull final LayoutInflater inflater, final ViewGroup container,
-                             final Bundle savedInstanceState) {
+    public View onCreateView(final LayoutInflater inflater, @Nullable final ViewGroup container,
+                             @Nullable final Bundle savedInstanceState) {
         super.onCreateView(inflater, container, savedInstanceState);
         binding = TunnelEditorFragmentBinding.inflate(inflater, container, false);
         binding.addOnPropertyChangedCallback(breakObjectOrientedLayeringHandler);
+        breakObjectOrientedLayeringHandlerReceivers.add(binding);
         binding.executePendingBindings();
         return binding.getRoot();
     }
 
+    @SuppressWarnings("unchecked")
     @Override
     public void onDestroyView() {
         binding = null;
+        for (final Object o : breakObjectOrientedLayeringHandlerReceivers) {
+            if (o instanceof Observable)
+                ((Observable)o).removeOnPropertyChangedCallback(breakObjectOrientedLayeringHandler);
+            else if (o instanceof ObservableList)
+                ((ObservableList)o).removeOnListChangedCallback(breakObjectListOrientedLayeringHandler);
+        }
         super.onDestroyView();
     }
 
@@ -153,6 +174,7 @@ public class TunnelEditorFragment extends BaseFragment implements AppExclusionLi
         }
         // Tell the activity to finish itself or go back to the detail view.
         getActivity().runOnUiThread(() -> {
+            // TODO(smaeul): Remove this hack when fixing the Config ViewModel
             // The selected tunnel has to actually change, but we have to remember this one.
             final Tunnel savedTunnel = tunnel;
             if (savedTunnel == getSelectedTunnel())
@@ -197,14 +219,14 @@ public class TunnelEditorFragment extends BaseFragment implements AppExclusionLi
     }
 
     @Override
-    public void onSaveInstanceState(@NonNull final Bundle outState) {
+    public void onSaveInstanceState(final Bundle outState) {
         outState.putParcelable(KEY_LOCAL_CONFIG, binding.getConfig());
         outState.putString(KEY_ORIGINAL_NAME, tunnel == null ? null : tunnel.getName());
         super.onSaveInstanceState(outState);
     }
 
     @Override
-    public void onSelectedTunnelChanged(final Tunnel oldTunnel, final Tunnel newTunnel) {
+    public void onSelectedTunnelChanged(@Nullable final Tunnel oldTunnel, @Nullable final Tunnel newTunnel) {
         tunnel = newTunnel;
         if (binding == null)
             return;
@@ -213,7 +235,7 @@ public class TunnelEditorFragment extends BaseFragment implements AppExclusionLi
             tunnel.getConfigAsync().thenAccept(a -> onConfigLoaded(tunnel.getName(), a));
     }
 
-    private void onTunnelCreated(final Tunnel newTunnel, final Throwable throwable) {
+    private void onTunnelCreated(final Tunnel newTunnel, @Nullable final Throwable throwable) {
         final String message;
         if (throwable == null) {
             tunnel = newTunnel;
@@ -232,7 +254,7 @@ public class TunnelEditorFragment extends BaseFragment implements AppExclusionLi
     }
 
     private void onTunnelRenamed(final Tunnel renamedTunnel, final Config newConfig,
-                                 final Throwable throwable) {
+                                 @Nullable final Throwable throwable) {
         final String message;
         if (throwable == null) {
             message = getString(R.string.tunnel_rename_success, renamedTunnel.getName());
@@ -251,7 +273,11 @@ public class TunnelEditorFragment extends BaseFragment implements AppExclusionLi
     }
 
     @Override
-    public void onViewStateRestored(final Bundle savedInstanceState) {
+    public void onViewStateRestored(@Nullable final Bundle savedInstanceState) {
+        if (binding == null) {
+            return;
+        }
+
         binding.setFragment(this);
 
         if (savedInstanceState == null) {
@@ -271,15 +297,16 @@ public class TunnelEditorFragment extends BaseFragment implements AppExclusionLi
 
     public void onRequestSetExcludedApplications(@SuppressWarnings("unused") final View view) {
         final FragmentManager fragmentManager = getFragmentManager();
-        if (fragmentManager != null) {
+        if (fragmentManager != null && binding != null) {
             final String[] excludedApps = Attribute.stringToList(binding.getConfig().getInterfaceSection().getExcludedApplications());
             final AppListDialogFragment fragment = AppListDialogFragment.newInstance(excludedApps, this);
-            fragment.show(getFragmentManager(), null);
+            fragment.show(fragmentManager, null);
         }
     }
 
     @Override
     public void onExcludedAppsSelected(final List<String> excludedApps) {
+        Objects.requireNonNull(binding, "Tried to set excluded apps while no view was loaded");
         binding.getConfig().getInterfaceSection().setExcludedApplications(Attribute.iterableToString(excludedApps));
     }
 

app/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java

@@ -18,8 +18,10 @@ import android.provider.OpenableColumns;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.design.widget.Snackbar;
+import android.support.v4.app.FragmentManager;
 import android.support.v7.app.AppCompatActivity;
 import android.support.v7.view.ActionMode;
+import android.support.v7.widget.RecyclerView;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.Menu;
@@ -27,6 +29,8 @@ import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
 
+import com.google.zxing.integration.android.IntentIntegrator;
+import com.google.zxing.integration.android.IntentResult;
 import com.wireguard.android.Application;
 import com.wireguard.android.R;
 import com.wireguard.android.activity.TunnelCreatorActivity;
@@ -35,9 +39,13 @@ import com.wireguard.android.databinding.TunnelListFragmentBinding;
 import com.wireguard.android.databinding.TunnelListItemBinding;
 import com.wireguard.android.model.Tunnel;
 import com.wireguard.android.util.ExceptionLoggers;
+import com.wireguard.android.util.ObservableSortedKeyedList;
+import com.wireguard.android.widget.MultiselectableRelativeLayout;
+import com.wireguard.android.widget.fab.FloatingActionsMenuRecyclerViewScrollListener;
 import com.wireguard.config.Config;
 
 import java.io.BufferedReader;
+import java.io.IOException;
 import java.io.InputStreamReader;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
@@ -60,20 +68,34 @@ public class TunnelListFragment extends BaseFragment {
     private static final String TAG = "WireGuard/" + TunnelListFragment.class.getSimpleName();
 
     private final ActionModeListener actionModeListener = new ActionModeListener();
-    private ActionMode actionMode;
-    private TunnelListFragmentBinding binding;
+    @Nullable private ActionMode actionMode;
+    @Nullable private TunnelListFragmentBinding binding;
 
     public boolean collapseActionMenu() {
-        if (binding.createMenu.isExpanded()) {
+        if (binding != null && binding.createMenu.isExpanded()) {
             binding.createMenu.collapse();
             return true;
         }
         return false;
     }
 
-    private void importTunnel(final Uri uri) {
+    private void importTunnel(@NonNull final String configText) {
+        try {
+            // Ensure the config text is parseable before proceeding…
+            Config.from(configText);
+
+            // Config text is valid, now create the tunnel…
+            final FragmentManager fragmentManager = getFragmentManager();
+            if (fragmentManager != null)
+                ConfigNamingDialogFragment.newInstance(configText).show(fragmentManager, null);
+        } catch (final Exception exception) {
+            onTunnelImportFinished(Collections.emptyList(), Collections.singletonList(exception));
+        }
+    }
+
+    private void importTunnel(@Nullable final Uri uri) {
         final Activity activity = getActivity();
-        if (activity == null)
+        if (activity == null || uri == null)
             return;
         final ContentResolver contentResolver = activity.getContentResolver();
 
@@ -165,21 +187,28 @@ public class TunnelListFragment extends BaseFragment {
     }
 
     @Override
-    public void onActivityResult(final int requestCode, final int resultCode, final Intent data) {
+    public void onActivityResult(final int requestCode, final int resultCode, @Nullable final Intent data) {
         switch (requestCode) {
             case REQUEST_IMPORT:
-                if (resultCode == Activity.RESULT_OK)
+                if (resultCode == Activity.RESULT_OK && data != null)
                     importTunnel(data.getData());
                 return;
+            case IntentIntegrator.REQUEST_CODE:
+                final IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
+                if (result != null && result.getContents() != null) {
+                    importTunnel(result.getContents());
+                }
+                return;
             default:
                 super.onActivityResult(requestCode, resultCode, data);
         }
     }
 
+    @SuppressWarnings("deprecation")
     @SuppressLint("ClickableViewAccessibility")
     @Override
-    public View onCreateView(@NonNull final LayoutInflater inflater, final ViewGroup container,
-                             final Bundle savedInstanceState) {
+    public View onCreateView(@NonNull final LayoutInflater inflater, @Nullable final ViewGroup container,
+                             @Nullable final Bundle savedInstanceState) {
         super.onCreateView(inflater, container, savedInstanceState);
         binding = TunnelListFragmentBinding.inflate(inflater, container, false);
 
@@ -189,6 +218,7 @@ public class TunnelListFragment extends BaseFragment {
             }
             return false;
         });
+        binding.tunnelList.setOnScrollListener(new FloatingActionsMenuRecyclerViewScrollListener(binding.createMenu));
         binding.executePendingBindings();
         return binding.getRoot();
     }
@@ -214,18 +244,42 @@ public class TunnelListFragment extends BaseFragment {
             binding.createMenu.collapse();
     }
 
+    public void onRequestScanQRCode(@SuppressWarnings("unused") final View view) {
+        final IntentIntegrator intentIntegrator = IntentIntegrator.forSupportFragment(this);
+        intentIntegrator.setOrientationLocked(false);
+        intentIntegrator.setBeepEnabled(false);
+        intentIntegrator.setPrompt(getString(R.string.qrcode_hint));
+        intentIntegrator.initiateScan(Collections.singletonList(IntentIntegrator.QR_CODE));
+
+        if (binding != null)
+            binding.createMenu.collapse();
+    }
+
     @Override
     public void onPause() {
-        binding.createMenu.collapse();
+        if (binding != null) {
+            binding.createMenu.collapse();
+        }
         super.onPause();
     }
 
-    @Override
-    public void onSelectedTunnelChanged(final Tunnel oldTunnel, final Tunnel newTunnel) {
-        // Do nothing.
+    private MultiselectableRelativeLayout viewForTunnel(final Tunnel tunnel, final List tunnels) {
+        return (MultiselectableRelativeLayout)binding.tunnelList.findViewHolderForAdapterPosition(tunnels.indexOf(tunnel)).itemView;
     }
 
-    private void onTunnelDeletionFinished(final Integer count, final Throwable throwable) {
+    @Override
+    public void onSelectedTunnelChanged(@Nullable final Tunnel oldTunnel, @Nullable final Tunnel newTunnel) {
+        if (binding == null)
+            return;
+        Application.getTunnelManager().getTunnels().thenAccept(tunnels -> {
+            if (newTunnel != null)
+                viewForTunnel(newTunnel, tunnels).setSingleSelected(true);
+            if (oldTunnel != null)
+                viewForTunnel(oldTunnel, tunnels).setSingleSelected(false);
+        });
+    }
+
+    private void onTunnelDeletionFinished(final Integer count, @Nullable final Throwable throwable) {
         final String message;
         if (throwable == null) {
             message = getResources().getQuantityString(R.plurals.delete_success, count, count);
@@ -265,10 +319,35 @@ public class TunnelListFragment extends BaseFragment {
     }
 
     @Override
-    public void onViewStateRestored(final Bundle savedInstanceState) {
+    public void onSaveInstanceState(final Bundle outState) {
+        super.onSaveInstanceState(outState);
+
+        outState.putIntegerArrayList("CHECKED_ITEMS", actionModeListener.getCheckedItems());
+    }
+
+    @Override
+    public void onActivityCreated(@Nullable final Bundle savedInstanceState) {
+        super.onActivityCreated(savedInstanceState);
+
+        if (savedInstanceState != null) {
+            final Collection<Integer> checkedItems = savedInstanceState.getIntegerArrayList("CHECKED_ITEMS");
+            if (checkedItems != null) {
+                for (final Integer i : checkedItems)
+                    actionModeListener.setItemChecked(i, true);
+            }
+        }
+    }
+
+    @Override
+    public void onViewStateRestored(@Nullable final Bundle savedInstanceState) {
         super.onViewStateRestored(savedInstanceState);
+
+        if (binding == null) {
+            return;
+        }
+
         binding.setFragment(this);
-        binding.setTunnels(Application.getTunnelManager().getTunnels());
+        Application.getTunnelManager().getTunnels().thenAccept(binding::setTunnels);
         binding.setRowConfigurationHandler((ObservableKeyedRecyclerViewAdapter.RowConfigurationHandler<TunnelListItemBinding, Tunnel>) (binding, tunnel, position) -> {
             binding.setFragment(this);
             binding.getRoot().setOnClickListener(clicked -> {
@@ -283,38 +362,45 @@ public class TunnelListFragment extends BaseFragment {
                 return true;
             });
 
-            binding.getRoot().setActivated(actionModeListener.checkedItems.contains(position));
+            if (actionMode != null)
+                ((MultiselectableRelativeLayout)binding.getRoot()).setMultiSelected(actionModeListener.checkedItems.contains(position));
+            else
+                ((MultiselectableRelativeLayout)binding.getRoot()).setSingleSelected(getSelectedTunnel() == tunnel);
         });
     }
 
     private final class ActionModeListener implements ActionMode.Callback {
         private final Collection<Integer> checkedItems = new HashSet<>();
 
-        private Resources resources;
+        @Nullable private Resources resources;
 
         @Override
         public boolean onActionItemClicked(final ActionMode mode, final MenuItem item) {
             switch (item.getItemId()) {
                 case R.id.menu_action_delete:
-                    final Collection<Tunnel> tunnelsToDelete = new ArrayList<>();
-                    for (final Integer position : checkedItems) {
-                        tunnelsToDelete.add(Application.getTunnelManager().getTunnels().get(position));
-                    }
+                    final Iterable<Integer> copyCheckedItems = new HashSet<>(checkedItems);
+                    Application.getTunnelManager().getTunnels().thenAccept(tunnels -> {
+                        final Collection<Tunnel> tunnelsToDelete = new ArrayList<>();
+                        for (final Integer position : copyCheckedItems)
+                            tunnelsToDelete.add(tunnels.get(position));
 
-                    final CompletableFuture[] futures = StreamSupport.stream(tunnelsToDelete)
-                            .map(Tunnel::delete)
-                            .toArray(CompletableFuture[]::new);
-                    CompletableFuture.allOf(futures)
-                            .thenApply(x -> futures.length)
-                            .whenComplete(TunnelListFragment.this::onTunnelDeletionFinished);
+                        final CompletableFuture[] futures = StreamSupport.stream(tunnelsToDelete)
+                                .map(Tunnel::delete)
+                                .toArray(CompletableFuture[]::new);
+                        CompletableFuture.allOf(futures)
+                                .thenApply(x -> futures.length)
+                                .whenComplete(TunnelListFragment.this::onTunnelDeletionFinished);
 
+                    });
                     checkedItems.clear();
                     mode.finish();
                     return true;
                 case R.id.menu_action_select_all:
-                    for (int i = 0; i < Application.getTunnelManager().getTunnels().size(); ++i) {
-                        setItemChecked(i, true);
-                    }
+                    Application.getTunnelManager().getTunnels().thenAccept(tunnels -> {
+                        for (int i = 0; i < tunnels.size(); ++i) {
+                            setItemChecked(i, true);
+                        }
+                    });
                     return true;
                 default:
                     return false;
@@ -328,6 +414,7 @@ public class TunnelListFragment extends BaseFragment {
                 resources = getActivity().getResources();
             }
             mode.getMenuInflater().inflate(R.menu.tunnel_list_action_mode, menu);
+            binding.tunnelList.getAdapter().notifyDataSetChanged();
             return true;
         }
 
@@ -335,7 +422,6 @@ public class TunnelListFragment extends BaseFragment {
         public void onDestroyActionMode(final ActionMode mode) {
             actionMode = null;
             resources = null;
-
             checkedItems.clear();
             binding.tunnelList.getAdapter().notifyDataSetChanged();
         }
@@ -344,6 +430,10 @@ public class TunnelListFragment extends BaseFragment {
             setItemChecked(position, !checkedItems.contains(position));
         }
 
+        public ArrayList<Integer> getCheckedItems() {
+            return new ArrayList<>(checkedItems);
+        }
+
         void setItemChecked(final int position, final boolean checked) {
             if (checked) {
                 checkedItems.add(position);
@@ -351,13 +441,16 @@ public class TunnelListFragment extends BaseFragment {
                 checkedItems.remove(position);
             }
 
+            final RecyclerView.Adapter adapter = binding == null ? null : binding.tunnelList.getAdapter();
+
             if (actionMode == null && !checkedItems.isEmpty() && getActivity() != null) {
                 ((AppCompatActivity) getActivity()).startSupportActionMode(this);
             } else if (actionMode != null && checkedItems.isEmpty()) {
                 actionMode.finish();
             }
 
-            binding.tunnelList.getAdapter().notifyItemChanged(position);
+            if (adapter != null)
+                adapter.notifyItemChanged(position);
 
             updateTitle(actionMode);
         }

app/src/main/java/com/wireguard/android/model/ApplicationData.java

@@ -9,36 +9,32 @@ package com.wireguard.android.model;
 import android.databinding.BaseObservable;
 import android.databinding.Bindable;
 import android.graphics.drawable.Drawable;
-import android.support.annotation.NonNull;
 
 import com.wireguard.android.BR;
 import com.wireguard.util.Keyed;
 
 public class ApplicationData extends BaseObservable implements Keyed<String> {
 
-    @NonNull private final Drawable icon;
-    @NonNull private final String name;
-    @NonNull private final String packageName;
+    private final Drawable icon;
+    private final String name;
+    private final String packageName;
     private boolean excludedFromTunnel;
 
-    public ApplicationData(@NonNull final Drawable icon, @NonNull final String name, @NonNull final String packageName, final boolean excludedFromTunnel) {
+    public ApplicationData(final Drawable icon, final String name, final String packageName, final boolean excludedFromTunnel) {
         this.icon = icon;
         this.name = name;
         this.packageName = packageName;
         this.excludedFromTunnel = excludedFromTunnel;
     }
 
-    @NonNull
     public Drawable getIcon() {
         return icon;
     }
 
-    @NonNull
     public String getName() {
         return name;
     }
 
-    @NonNull
     public String getPackageName() {
         return packageName;
     }

app/src/main/java/com/wireguard/android/model/Tunnel.java

@@ -8,13 +8,12 @@ package com.wireguard.android.model;
 
 import android.databinding.BaseObservable;
 import android.databinding.Bindable;
-import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 
 import com.wireguard.android.BR;
 import com.wireguard.android.util.ExceptionLoggers;
-import com.wireguard.util.Keyed;
 import com.wireguard.config.Config;
+import com.wireguard.util.Keyed;
 
 import java.util.regex.Pattern;
 
@@ -30,20 +29,20 @@ public class Tunnel extends BaseObservable implements Keyed<String> {
     private static final Pattern NAME_PATTERN = Pattern.compile("[a-zA-Z0-9_=+.-]{1,15}");
 
     private final TunnelManager manager;
-    private Config config;
+    @Nullable private Config config;
     private String name;
     private State state;
-    private Statistics statistics;
+    @Nullable private Statistics statistics;
 
-    Tunnel(@NonNull final TunnelManager manager, @NonNull final String name,
-           @Nullable final Config config, @NonNull final State state) {
+    Tunnel(final TunnelManager manager, final String name,
+           @Nullable final Config config, final State state) {
         this.manager = manager;
         this.name = name;
         this.config = config;
         this.state = state;
     }
 
-    public static boolean isNameInvalid(@NonNull final CharSequence name) {
+    public static boolean isNameInvalid(final CharSequence name) {
         return !NAME_PATTERN.matcher(name).matches();
     }
 
@@ -51,7 +50,7 @@ public class Tunnel extends BaseObservable implements Keyed<String> {
         return manager.delete(this);
     }
 
-    @Bindable
+    @Bindable @Nullable
     public Config getConfig() {
         if (config == null)
             manager.getTunnelConfig(this).whenComplete(ExceptionLoggers.E);
@@ -83,7 +82,7 @@ public class Tunnel extends BaseObservable implements Keyed<String> {
         return TunnelManager.getTunnelState(this);
     }
 
-    @Bindable
+    @Bindable @Nullable
     public Statistics getStatistics() {
         // FIXME: Check age of statistics.
         if (statistics == null)
@@ -118,25 +117,26 @@ public class Tunnel extends BaseObservable implements Keyed<String> {
         return state;
     }
 
-    Statistics onStatisticsChanged(final Statistics statistics) {
+    @Nullable
+    Statistics onStatisticsChanged(@Nullable final Statistics statistics) {
         this.statistics = statistics;
         notifyPropertyChanged(BR.statistics);
         return statistics;
     }
 
-    public CompletionStage<Config> setConfig(@NonNull final Config config) {
+    public CompletionStage<Config> setConfig(final Config config) {
         if (!config.equals(this.config))
             return manager.setTunnelConfig(this, config);
         return CompletableFuture.completedFuture(this.config);
     }
 
-    public CompletionStage<String> setName(@NonNull final String name) {
+    public CompletionStage<String> setName(final String name) {
         if (!name.equals(this.name))
             return manager.setTunnelName(this, name);
         return CompletableFuture.completedFuture(this.name);
     }
 
-    public CompletionStage<State> setState(@NonNull final State state) {
+    public CompletionStage<State> setState(final State state) {
         if (state != this.state)
             return manager.setTunnelState(this, state);
         return CompletableFuture.completedFuture(this.state);
@@ -152,6 +152,5 @@ public class Tunnel extends BaseObservable implements Keyed<String> {
         }
     }
 
-    public static class Statistics extends BaseObservable {
-    }
+    public static class Statistics extends BaseObservable { }
 }

app/src/main/java/com/wireguard/android/model/TunnelManager.java

@@ -11,15 +11,15 @@ import android.content.Context;
 import android.content.Intent;
 import android.databinding.BaseObservable;
 import android.databinding.Bindable;
-import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 
 import com.wireguard.android.Application;
 import com.wireguard.android.BR;
+import com.wireguard.android.R;
 import com.wireguard.android.configStore.ConfigStore;
 import com.wireguard.android.model.Tunnel.State;
 import com.wireguard.android.model.Tunnel.Statistics;
 import com.wireguard.android.util.ExceptionLoggers;
-import com.wireguard.android.util.ObservableKeyedList;
 import com.wireguard.android.util.ObservableSortedKeyedArrayList;
 import com.wireguard.android.util.ObservableSortedKeyedList;
 import com.wireguard.config.Config;
@@ -47,9 +47,10 @@ public final class TunnelManager extends BaseObservable {
     private static final String KEY_RUNNING_TUNNELS = "enabled_configs";
 
     private final ConfigStore configStore;
-    private final ObservableSortedKeyedList<String, Tunnel> tunnels =
-            new ObservableSortedKeyedArrayList<>(COMPARATOR);
-    private Tunnel lastUsedTunnel;
+    private final Context context = Application.get();
+    private final CompletableFuture<ObservableSortedKeyedList<String, Tunnel>> completableTunnels = new CompletableFuture<>();
+    private final ObservableSortedKeyedList<String, Tunnel> tunnels = new ObservableSortedKeyedArrayList<>(COMPARATOR);
+    @Nullable private Tunnel lastUsedTunnel;
     private boolean haveLoaded;
     private final ArrayList<CompletableFuture<Void>> delayedLoadRestoreTunnels = new ArrayList<>();
 
@@ -57,17 +58,17 @@ public final class TunnelManager extends BaseObservable {
         this.configStore = configStore;
     }
 
-    private Tunnel addToList(final String name, final Config config, final State state) {
+    private Tunnel addToList(final String name, @Nullable final Config config, final State state) {
         final Tunnel tunnel = new Tunnel(this, name, config, state);
         tunnels.add(tunnel);
         return tunnel;
     }
 
-    public CompletionStage<Tunnel> create(@NonNull final String name, final Config config) {
+    public CompletionStage<Tunnel> create(final String name, @Nullable final Config config) {
         if (Tunnel.isNameInvalid(name))
-            return CompletableFuture.failedFuture(new IllegalArgumentException("Invalid name"));
+            return CompletableFuture.failedFuture(new IllegalArgumentException(context.getString(R.string.tunnel_error_invalid_name)));
         if (tunnels.containsKey(name)) {
-            final String message = "Tunnel " + name + " already exists";
+            final String message = context.getString(R.string.tunnel_error_already_exists, name);
             return CompletableFuture.failedFuture(new IllegalArgumentException(message));
         }
         return Application.getAsyncWorker().supplyAsync(() -> configStore.create(name, config))
@@ -102,7 +103,7 @@ public final class TunnelManager extends BaseObservable {
         });
     }
 
-    @Bindable
+    @Bindable @Nullable
     public Tunnel getLastUsedTunnel() {
         return lastUsedTunnel;
     }
@@ -122,8 +123,8 @@ public final class TunnelManager extends BaseObservable {
                 .thenApply(tunnel::onStatisticsChanged);
     }
 
-    public ObservableKeyedList<String, Tunnel> getTunnels() {
-        return tunnels;
+    public CompletableFuture<ObservableSortedKeyedList<String, Tunnel>> getTunnels() {
+        return completableTunnels;
     }
 
     public void onCreate() {
@@ -153,6 +154,8 @@ public final class TunnelManager extends BaseObservable {
                     f.completeExceptionally(t);
             }
         });
+
+        completableTunnels.complete(tunnels);
     }
 
     public void refreshTunnelStates() {
@@ -191,7 +194,7 @@ public final class TunnelManager extends BaseObservable {
         Application.getSharedPreferences().edit().putStringSet(KEY_RUNNING_TUNNELS, runningTunnels).apply();
     }
 
-    private void setLastUsedTunnel(final Tunnel tunnel) {
+    private void setLastUsedTunnel(@Nullable final Tunnel tunnel) {
         if (tunnel == lastUsedTunnel)
             return;
         lastUsedTunnel = tunnel;
@@ -211,9 +214,9 @@ public final class TunnelManager extends BaseObservable {
 
     CompletionStage<String> setTunnelName(final Tunnel tunnel, final String name) {
         if (Tunnel.isNameInvalid(name))
-            return CompletableFuture.failedFuture(new IllegalArgumentException("Invalid name"));
+            return CompletableFuture.failedFuture(new IllegalArgumentException(context.getString(R.string.tunnel_error_invalid_name)));
         if (tunnels.containsKey(name)) {
-            final String message = "Tunnel " + name + " already exists";
+            final String message = context.getString(R.string.tunnel_error_already_exists, name);
             return CompletableFuture.failedFuture(new IllegalArgumentException(message));
         }
         final State originalState = tunnel.getState();
@@ -256,7 +259,7 @@ public final class TunnelManager extends BaseObservable {
 
     public static final class IntentReceiver extends BroadcastReceiver {
         @Override
-        public void onReceive(final Context context, final Intent intent) {
+        public void onReceive(final Context context, @Nullable final Intent intent) {
             final TunnelManager manager = Application.getTunnelManager();
             if (intent == null)
                 return;
@@ -286,10 +289,12 @@ public final class TunnelManager extends BaseObservable {
             final String tunnelName = intent.getStringExtra("tunnel");
             if (tunnelName == null)
                 return;
-            final Tunnel tunnel = manager.getTunnels().get(tunnelName);
-            if (tunnel == null)
-                return;
-            manager.setTunnelState(tunnel, state);
+            manager.getTunnels().thenAccept(tunnels -> {
+                final Tunnel tunnel = tunnels.get(tunnelName);
+                if (tunnel == null)
+                    return;
+                manager.setTunnelState(tunnel, state);
+            });
         }
     }
 }

app/src/main/java/com/wireguard/android/preference/LogExporterPreference.java

@@ -10,6 +10,7 @@ import android.Manifest;
 import android.content.Context;
 import android.content.pm.PackageManager;
 import android.os.Environment;
+import android.support.annotation.Nullable;
 import android.support.design.widget.Snackbar;
 import android.support.v7.preference.Preference;
 import android.util.AttributeSet;
@@ -33,7 +34,7 @@ import java.io.InputStreamReader;
 public class LogExporterPreference extends Preference {
     private static final String TAG = "WireGuard/" + LogExporterPreference.class.getSimpleName();
 
-    private String exportedFilePath;
+    @Nullable private String exportedFilePath;
 
     public LogExporterPreference(final Context context, final AttributeSet attrs) {
         super(context, attrs);
@@ -73,7 +74,7 @@ public class LogExporterPreference extends Preference {
         }).whenComplete(this::exportLogComplete);
     }
 
-    private void exportLogComplete(final String filePath, final Throwable throwable) {
+    private void exportLogComplete(final String filePath, @Nullable final Throwable throwable) {
         if (throwable != null) {
             final String error = ExceptionLoggers.unwrapMessage(throwable);
             final String message = getContext().getString(R.string.log_export_error, error);

app/src/main/java/com/wireguard/android/preference/ToolsInstallerPreference.java

@@ -7,7 +7,7 @@
 package com.wireguard.android.preference;
 
 import android.content.Context;
-import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.support.v7.preference.Preference;
 import android.util.AttributeSet;
 
@@ -43,7 +43,7 @@ public class ToolsInstallerPreference extends Preference {
         Application.getAsyncWorker().supplyAsync(Application.getToolsInstaller()::areInstalled).whenComplete(this::onCheckResult);
     }
 
-    private void onCheckResult(final int state, final Throwable throwable) {
+    private void onCheckResult(final int state, @Nullable final Throwable throwable) {
         if (throwable != null || state == ToolsInstaller.ERROR)
             setState(State.INITIAL);
         else if ((state & ToolsInstaller.YES) == ToolsInstaller.YES)
@@ -62,7 +62,7 @@ public class ToolsInstallerPreference extends Preference {
         Application.getAsyncWorker().supplyAsync(Application.getToolsInstaller()::install).whenComplete(this::onInstallResult);
     }
 
-    private void onInstallResult(final Integer result, final Throwable throwable) {
+    private void onInstallResult(final Integer result, @Nullable final Throwable throwable) {
         if (throwable != null)
             setState(State.FAILURE);
         else if ((result & (ToolsInstaller.YES | ToolsInstaller.MAGISK)) == (ToolsInstaller.YES | ToolsInstaller.MAGISK))
@@ -73,7 +73,7 @@ public class ToolsInstallerPreference extends Preference {
             setState(State.FAILURE);
     }
 
-    private void setState(@NonNull final State state) {
+    private void setState(final State state) {
         if (this.state == state)
             return;
         this.state = state;

app/src/main/java/com/wireguard/android/preference/VersionPreference.java

@@ -9,6 +9,7 @@ import android.content.ActivityNotFoundException;
 import android.content.Context;
 import android.content.Intent;
 import android.net.Uri;
+import android.support.annotation.Nullable;
 import android.support.v7.preference.Preference;
 import android.util.AttributeSet;
 
@@ -17,12 +18,12 @@ import com.wireguard.android.BuildConfig;
 import com.wireguard.android.R;
 
 public class VersionPreference extends Preference {
-    private String versionSummary;
+    @Nullable private String versionSummary;
 
     public VersionPreference(final Context context, final AttributeSet attrs) {
         super(context, attrs);
 
-        Application.onHaveBackend(backend -> {
+        Application.getBackendAsync().thenAccept(backend -> {
             versionSummary = getContext().getString(R.string.version_summary_checking, backend.getTypeName().toLowerCase());
             Application.getAsyncWorker().supplyAsync(backend::getVersion).whenComplete((version, exception) -> {
                 versionSummary = exception == null
@@ -33,7 +34,7 @@ public class VersionPreference extends Preference {
         });
     }
 
-    @Override
+    @Override @Nullable
     public CharSequence getSummary() {
         return versionSummary;
     }

app/src/main/java/com/wireguard/android/preference/ZipExporterPreference.java

@@ -10,6 +10,7 @@ import android.Manifest;
 import android.content.Context;
 import android.content.pm.PackageManager;
 import android.os.Environment;
+import android.support.annotation.Nullable;
 import android.support.design.widget.Snackbar;
 import android.support.v7.preference.Preference;
 import android.util.AttributeSet;
@@ -40,14 +41,17 @@ import java9.util.concurrent.CompletableFuture;
 public class ZipExporterPreference extends Preference {
     private static final String TAG = "WireGuard/" + ZipExporterPreference.class.getSimpleName();
 
-    private String exportedFilePath;
+    @Nullable private String exportedFilePath;
 
     public ZipExporterPreference(final Context context, final AttributeSet attrs) {
         super(context, attrs);
     }
 
     private void exportZip() {
-        final List<Tunnel> tunnels = new ArrayList<>(Application.getTunnelManager().getTunnels());
+        Application.getTunnelManager().getTunnels().thenAccept(this::exportZip);
+    }
+
+    private void exportZip(final List<Tunnel> tunnels) {
         final List<CompletableFuture<Config>> futureConfigs = new ArrayList<>(tunnels.size());
         for (final Tunnel tunnel : tunnels)
             futureConfigs.add(tunnel.getConfigAsync().toCompletableFuture());
@@ -79,7 +83,7 @@ public class ZipExporterPreference extends Preference {
                 }).whenComplete(this::exportZipComplete));
     }
 
-    private void exportZipComplete(final String filePath, final Throwable throwable) {
+    private void exportZipComplete(@Nullable final String filePath, @Nullable final Throwable throwable) {
         if (throwable != null) {
             final String error = ExceptionLoggers.unwrapMessage(throwable);
             final String message = getContext().getString(R.string.zip_export_error, error);

app/src/main/java/com/wireguard/android/util/ExceptionLoggers.java

@@ -6,8 +6,9 @@
 
 package com.wireguard.android.util;
 
-import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.util.Log;
+
 import java9.util.concurrent.CompletionException;
 import java9.util.function.BiConsumer;
 
@@ -34,7 +35,6 @@ public enum ExceptionLoggers implements BiConsumer<Object, Throwable> {
         return throwable;
     }
 
-    @NonNull
     public static String unwrapMessage(Throwable throwable) {
         throwable = unwrap(throwable);
         final String message = throwable.getMessage();
@@ -44,7 +44,7 @@ public enum ExceptionLoggers implements BiConsumer<Object, Throwable> {
     }
 
     @Override
-    public void accept(final Object result, final Throwable throwable) {
+    public void accept(final Object result, @Nullable final Throwable throwable) {
         if (throwable != null)
             Log.println(Log.ERROR, TAG, Log.getStackTraceString(throwable));
         else if (priority <= Log.DEBUG)

app/src/main/java/com/wireguard/android/util/FragmentUtils.java

@@ -11,7 +11,11 @@ import android.view.ContextThemeWrapper;
 
 import com.wireguard.android.activity.SettingsActivity;
 
-public class FragmentUtils {
+public final class FragmentUtils {
+
+    private FragmentUtils() {
+        // Prevent instantiation
+    }
 
     public static SettingsActivity getPrefActivity(final Preference preference) {
         final Context context = preference.getContext();

app/src/main/java/com/wireguard/android/util/ObservableKeyedArrayList.java

@@ -7,7 +7,7 @@
 package com.wireguard.android.util;
 
 import android.databinding.ObservableArrayList;
-import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 
 import com.wireguard.util.Keyed;
 
@@ -25,28 +25,28 @@ import java.util.Objects;
 public class ObservableKeyedArrayList<K, E extends Keyed<? extends K>>
         extends ObservableArrayList<E> implements ObservableKeyedList<K, E> {
     @Override
-    public boolean add(final E e) {
+    public boolean add(@Nullable final E e) {
         if (e == null)
             throw new NullPointerException("Trying to add a null element");
         return super.add(e);
     }
 
     @Override
-    public void add(final int index, final E e) {
+    public void add(final int index, @Nullable final E e) {
         if (e == null)
             throw new NullPointerException("Trying to add a null element");
         super.add(index, e);
     }
 
     @Override
-    public boolean addAll(@NonNull final Collection<? extends E> c) {
+    public boolean addAll(final Collection<? extends E> c) {
         if (c.contains(null))
             throw new NullPointerException("Trying to add a collection with null element(s)");
         return super.addAll(c);
     }
 
     @Override
-    public boolean addAll(final int index, @NonNull final Collection<? extends E> c) {
+    public boolean addAll(final int index, final Collection<? extends E> c) {
         if (c.contains(null))
             throw new NullPointerException("Trying to add a collection with null element(s)");
         return super.addAll(index, c);
@@ -65,13 +65,13 @@ public class ObservableKeyedArrayList<K, E extends Keyed<? extends K>>
         return indexOfKey(key) >= 0;
     }
 
-    @Override
+    @Override @Nullable
     public E get(final K key) {
         final int index = indexOfKey(key);
         return index >= 0 ? get(index) : null;
     }
 
-    @Override
+    @Override @Nullable
     public E getLast(final K key) {
         final int index = lastIndexOfKey(key);
         return index >= 0 ? get(index) : null;
@@ -100,7 +100,7 @@ public class ObservableKeyedArrayList<K, E extends Keyed<? extends K>>
     }
 
     @Override
-    public E set(final int index, final E e) {
+    public E set(final int index, @Nullable final E e) {
         if (e == null)
             throw new NullPointerException("Trying to set a null key");
         return super.set(index, e);

app/src/main/java/com/wireguard/android/util/ObservableSortedKeyedArrayList.java

@@ -6,7 +6,7 @@
 
 package com.wireguard.android.util;
 
-import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 
 import com.wireguard.util.Keyed;
 import com.wireguard.util.SortedKeyedList;
@@ -29,6 +29,7 @@ import java.util.Spliterator;
 
 public class ObservableSortedKeyedArrayList<K, E extends Keyed<? extends K>>
         extends ObservableKeyedArrayList<K, E> implements ObservableSortedKeyedList<K, E> {
+    @Nullable
     private final Comparator<? super K> comparator;
     private final transient KeyList<K, E> keyList = new KeyList<>(this);
 
@@ -75,7 +76,7 @@ public class ObservableSortedKeyedArrayList<K, E extends Keyed<? extends K>>
     }
 
     @Override
-    public boolean addAll(@NonNull final Collection<? extends E> c) {
+    public boolean addAll(final Collection<? extends E> c) {
         boolean didChange = false;
         for (final E e : c)
             if (add(e))
@@ -84,12 +85,13 @@ public class ObservableSortedKeyedArrayList<K, E extends Keyed<? extends K>>
     }
 
     @Override
-    public boolean addAll(int index, @NonNull final Collection<? extends E> c) {
+    public boolean addAll(int index, final Collection<? extends E> c) {
         for (final E e : c)
             add(index++, e);
         return true;
     }
 
+    @Nullable
     @Override
     public Comparator<? super K> comparator() {
         return comparator;
@@ -128,7 +130,6 @@ public class ObservableSortedKeyedArrayList<K, E extends Keyed<? extends K>>
     }
 
     @Override
-    @NonNull
     public Set<K> keySet() {
         return keyList;
     }
@@ -168,7 +169,6 @@ public class ObservableSortedKeyedArrayList<K, E extends Keyed<? extends K>>
     }
 
     @Override
-    @NonNull
     public Collection<E> values() {
         return this;
     }

app/src/main/java/com/wireguard/android/util/RootShell.java

@@ -7,8 +7,10 @@
 package com.wireguard.android.util;
 
 import android.content.Context;
+import android.support.annotation.Nullable;
 import android.util.Log;
 
+import com.wireguard.android.BuildConfig;
 import com.wireguard.android.R;
 
 import java.io.BufferedReader;
@@ -34,18 +36,18 @@ public class RootShell {
     private final File localTemporaryDir;
     private final Object lock = new Object();
     private final String preamble;
-    private Process process;
-    private BufferedReader stderr;
-    private OutputStreamWriter stdin;
-    private BufferedReader stdout;
+    @Nullable private Process process;
+    @Nullable private BufferedReader stderr;
+    @Nullable private OutputStreamWriter stdin;
+    @Nullable private BufferedReader stdout;
 
     public RootShell(final Context context) {
         deviceNotRootedMessage = context.getString(R.string.error_root);
         final File cacheDir = context.getCacheDir();
         localBinaryDir = new File(cacheDir, "bin");
         localTemporaryDir = new File(cacheDir, "tmp");
-        preamble = String.format("export CALLING_PACKAGE=com.wireguard.android PATH=\"%s:$PATH\" TMPDIR='%s'; id -u\n",
-                localBinaryDir, localTemporaryDir);
+        preamble = String.format("export CALLING_PACKAGE=%s PATH=\"%s:$PATH\" TMPDIR='%s'; id -u\n",
+                BuildConfig.APPLICATION_ID, localBinaryDir, localTemporaryDir);
     }
 
     private static boolean isExecutableInPath(final String name) {
@@ -80,7 +82,7 @@ public class RootShell {
      * @param command Command to run as root.
      * @return The exit value of the command.
      */
-    public int run(final Collection<String> output, final String command)
+    public int run(@Nullable final Collection<String> output, final String command)
             throws IOException, NoRootException {
         synchronized (lock) {
             /* Start inside synchronized block to prevent a concurrent call to stop(). */

app/src/main/java/com/wireguard/android/util/SharedLibraryLoader.java

@@ -19,8 +19,7 @@ import java.util.zip.ZipFile;
 public final class SharedLibraryLoader {
     private static final String TAG = "WireGuard/" + SharedLibraryLoader.class.getSimpleName();
 
-    private SharedLibraryLoader() {
-    }
+    private SharedLibraryLoader() { }
 
     public static void loadSharedLibrary(final Context context, final String libName) {
         Throwable noAbiException;

app/src/main/java/com/wireguard/android/util/ToolsInstaller.java

@@ -7,6 +7,7 @@
 package com.wireguard.android.util;
 
 import android.content.Context;
+import android.support.annotation.Nullable;
 import android.system.OsConstants;
 import android.util.Log;
 
@@ -39,20 +40,21 @@ public final class ToolsInstaller {
             new File("/system/xbin"),
             new File("/system/bin"),
     };
-    private static final File INSTALL_DIR = getInstallDir();
+    @Nullable private static final File INSTALL_DIR = getInstallDir();
     private static final String TAG = "WireGuard/" + ToolsInstaller.class.getSimpleName();
 
     private final File localBinaryDir;
     private final Object lock = new Object();
     private final File nativeLibraryDir;
-    private Boolean areToolsAvailable;
-    private Boolean installAsMagiskModule;
+    @Nullable private Boolean areToolsAvailable;
+    @Nullable private Boolean installAsMagiskModule;
 
     public ToolsInstaller(final Context context) {
         localBinaryDir = new File(context.getCacheDir(), "bin");
         nativeLibraryDir = new File(context.getApplicationInfo().nativeLibraryDir);
     }
 
+    @Nullable
     private static File getInstallDir() {
         final String path = System.getenv("PATH");
         if (path == null)

app/src/main/java/com/wireguard/android/widget/KeyInputFilter.java

@@ -6,6 +6,7 @@
 
 package com.wireguard.android.widget;
 
+import android.support.annotation.Nullable;
 import android.text.InputFilter;
 import android.text.SpannableStringBuilder;
 import android.text.Spanned;
@@ -25,7 +26,7 @@ public class KeyInputFilter implements InputFilter {
         return new KeyInputFilter();
     }
 
-    @Override
+    @Override @Nullable
     public CharSequence filter(final CharSequence source,
                                final int sStart, final int sEnd,
                                final Spanned dest,

app/src/main/java/com/wireguard/android/widget/MultiselectableRelativeLayout.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright © 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.android.widget;
+
+import android.content.Context;
+import android.util.AttributeSet;
+import android.widget.RelativeLayout;
+
+import com.wireguard.android.R;
+
+public class MultiselectableRelativeLayout extends RelativeLayout {
+    public MultiselectableRelativeLayout(final Context context) {
+        super(context);
+    }
+    public MultiselectableRelativeLayout(final Context context, final AttributeSet attrs) {
+        super(context, attrs);
+    }
+    public MultiselectableRelativeLayout(final Context context, final AttributeSet attrs, final int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+    }
+    public MultiselectableRelativeLayout(final Context context, final AttributeSet attrs, final int defStyleAttr, final int defStyleRes) {
+        super(context, attrs, defStyleAttr, defStyleRes);
+    }
+
+    private static final int[] STATE_MULTISELECTED = { R.attr.state_multiselected };
+
+    private boolean multiselected;
+
+    @Override
+    protected int[] onCreateDrawableState(final int extraSpace) {
+        if (multiselected) {
+            final int[] drawableState = super.onCreateDrawableState(extraSpace + 1);
+            mergeDrawableStates(drawableState, STATE_MULTISELECTED);
+            return drawableState;
+        }
+        return super.onCreateDrawableState(extraSpace);
+    }
+
+    public void setMultiSelected(final boolean on) {
+        if (!multiselected) {
+            multiselected = true;
+            refreshDrawableState();
+        }
+        setActivated(on);
+    }
+
+    public void setSingleSelected(final boolean on) {
+        if (multiselected) {
+            multiselected = false;
+            refreshDrawableState();
+        }
+        setActivated(on);
+    }
+}

app/src/main/java/com/wireguard/android/widget/NameInputFilter.java

@@ -6,6 +6,7 @@
 
 package com.wireguard.android.widget;
 
+import android.support.annotation.Nullable;
 import android.text.InputFilter;
 import android.text.SpannableStringBuilder;
 import android.text.Spanned;
@@ -25,7 +26,7 @@ public class NameInputFilter implements InputFilter {
         return new NameInputFilter();
     }
 
-    @Override
+    @Override @Nullable
     public CharSequence filter(final CharSequence source,
                                final int sStart, final int sEnd,
                                final Spanned dest,

app/src/main/java/com/wireguard/android/widget/SlashDrawable.java

@@ -25,11 +25,9 @@ import android.graphics.drawable.Drawable;
 import android.os.Build;
 import android.support.annotation.ColorInt;
 import android.support.annotation.IntRange;
-import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.util.FloatProperty;
 
-
 @TargetApi(Build.VERSION_CODES.N)
 public class SlashDrawable extends Drawable {
 
@@ -53,26 +51,24 @@ public class SlashDrawable extends Drawable {
     // Draw the slash washington-monument style; rotate to no-u-turn style
     private static final float DEFAULT_ROTATION = -45f;
 
-    private Drawable mDrawable;
+    private final Drawable mDrawable;
     private final RectF mSlashRect = new RectF(0, 0, 0, 0);
     private float mRotation;
     private boolean mSlashed;
-    private Mode mTintMode;
-    private ColorStateList mTintList;
     private boolean mAnimationEnabled = true;
 
     public SlashDrawable(final Drawable d) {
-        setDrawable(d);
+        mDrawable = d;
     }
 
     @Override
     public int getIntrinsicHeight() {
-        return mDrawable != null ? mDrawable.getIntrinsicHeight(): 0;
+        return mDrawable.getIntrinsicHeight();
     }
 
     @Override
     public int getIntrinsicWidth() {
-        return mDrawable != null ? mDrawable.getIntrinsicWidth(): 0;
+        return mDrawable.getIntrinsicWidth();
     }
 
     @Override
@@ -81,17 +77,6 @@ public class SlashDrawable extends Drawable {
         mDrawable.setBounds(bounds);
     }
 
-    public void setDrawable(final Drawable d) {
-        mDrawable = d;
-        mDrawable.setCallback(getCallback());
-        mDrawable.setBounds(getBounds());
-        if (mTintMode != null)
-            mDrawable.setTintMode(mTintMode);
-        if (mTintList != null)
-            mDrawable.setTintList(mTintList);
-        invalidateSelf();
-    }
-
     public void setRotation(final float rotation) {
         if (mRotation == rotation)
             return;
@@ -139,7 +124,7 @@ public class SlashDrawable extends Drawable {
 
     @SuppressWarnings("deprecation")
     @Override
-    public void draw(@NonNull final Canvas canvas) {
+    public void draw(final Canvas canvas) {
         canvas.save();
         final Matrix m = new Matrix();
         final int width = getBounds().width();
@@ -201,7 +186,6 @@ public class SlashDrawable extends Drawable {
 
     @Override
     public void setTintList(@Nullable final ColorStateList tint) {
-        mTintList = tint;
         super.setTintList(tint);
         setDrawableTintList(tint);
         mPaint.setColor(tint == null ? 0 : tint.getDefaultColor());
@@ -213,8 +197,7 @@ public class SlashDrawable extends Drawable {
     }
 
     @Override
-    public void setTintMode(@NonNull final Mode tintMode) {
-        mTintMode = tintMode;
+    public void setTintMode(final Mode tintMode) {
         super.setTintMode(tintMode);
         mDrawable.setTintMode(tintMode);
     }

app/src/main/java/com/wireguard/android/widget/ToggleSwitch.java

@@ -7,22 +7,23 @@ package com.wireguard.android.widget;
 
 import android.content.Context;
 import android.os.Parcelable;
+import android.support.annotation.Nullable;
 import android.util.AttributeSet;
 import android.widget.Switch;
 
 public class ToggleSwitch extends Switch {
     private boolean isRestoringState;
-    private OnBeforeCheckedChangeListener listener;
-
-    @SuppressWarnings({"SameParameterValue", "WeakerAccess"})
-    public ToggleSwitch(final Context context, final AttributeSet attrs) {
-        super(context, attrs);
-    }
+    @Nullable private OnBeforeCheckedChangeListener listener;
 
     public ToggleSwitch(final Context context) {
         this(context, null);
     }
 
+    @SuppressWarnings({"SameParameterValue", "WeakerAccess"})
+    public ToggleSwitch(final Context context, @Nullable final AttributeSet attrs) {
+        super(context, attrs);
+    }
+
     @Override
     public void onRestoreInstanceState(final Parcelable state) {
         isRestoringState = true;

app/src/main/java/com/wireguard/android/widget/fab/FloatingActionButtonBehavior.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright © 2018 Harsh Shandilya <msfjarvis@gmail.com>
+ * Copyright © 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.android.widget.fab;
+
+import android.animation.Animator;
+import android.animation.AnimatorListenerAdapter;
+import android.animation.TimeInterpolator;
+import android.animation.ValueAnimator;
+import android.content.Context;
+import android.support.design.widget.CoordinatorLayout;
+import android.support.design.widget.Snackbar;
+import android.support.v4.view.animation.FastOutSlowInInterpolator;
+import android.util.AttributeSet;
+import android.view.View;
+
+public class FloatingActionButtonBehavior extends CoordinatorLayout.Behavior<FloatingActionsMenu> {
+
+    public FloatingActionButtonBehavior(final Context context, final AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    public boolean layoutDependsOn(final CoordinatorLayout parent, final FloatingActionsMenu child,
+                                   final View dependency) {
+        return dependency instanceof Snackbar.SnackbarLayout;
+    }
+
+    private static final long ANIMATION_DURATION = 250;
+    private static final TimeInterpolator FAST_OUT_SLOW_IN_INTERPOLATOR = new FastOutSlowInInterpolator();
+
+    private static void animateChange(final FloatingActionsMenu child, final float destination, final float fullSpan) {
+        final float origin = child.getBehaviorYTranslation();
+        if (Math.abs(destination - origin) < fullSpan / 2) {
+            child.setBehaviorYTranslation(destination);
+            return;
+        }
+        final ValueAnimator animator = new ValueAnimator();
+        animator.setFloatValues(origin, destination);
+        animator.setInterpolator(FAST_OUT_SLOW_IN_INTERPOLATOR);
+        animator.setDuration((long)(ANIMATION_DURATION * (Math.abs(destination - origin) / fullSpan)));
+        animator.addListener(new AnimatorListenerAdapter() {
+            @Override
+            public void onAnimationEnd(final Animator a) {
+                child.setBehaviorYTranslation(destination);
+            }
+        });
+        animator.addUpdateListener(a -> child.setBehaviorYTranslation((float)a.getAnimatedValue()));
+        animator.start();
+    }
+
+    @Override
+    public boolean onDependentViewChanged(final CoordinatorLayout parent, final FloatingActionsMenu child,
+                                          final View dependency) {
+        animateChange(child, Math.min(0, dependency.getTranslationY() - dependency.getMeasuredHeight()), dependency.getMeasuredHeight());
+        return true;
+    }
+
+    @Override
+    public void onDependentViewRemoved(final CoordinatorLayout parent, final FloatingActionsMenu child,
+                                       final View dependency) {
+        animateChange(child, 0, dependency.getMeasuredHeight());
+    }
+}

app/src/main/java/com/wireguard/android/widget/fab/FloatingActionsMenu.java

@@ -17,10 +17,11 @@ import android.graphics.Canvas;
 import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 import android.graphics.drawable.LayerDrawable;
+import android.os.Build;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.support.annotation.Keep;
-import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.support.design.widget.FloatingActionButton;
 import android.support.v4.content.res.ResourcesCompat;
 import android.support.v7.widget.AppCompatTextView;
@@ -57,32 +58,34 @@ public class FloatingActionsMenu extends ViewGroup {
     private boolean mExpanded;
     private final AnimatorSet mExpandAnimation = new AnimatorSet().setDuration(ANIMATION_DURATION);
     private final AnimatorSet mCollapseAnimation = new AnimatorSet().setDuration(ANIMATION_DURATION);
-    private FloatingActionButton mAddButton;
-    private RotatingDrawable mRotatingDrawable;
+    @Nullable private FloatingActionButton mAddButton;
+    @Nullable private RotatingDrawable mRotatingDrawable;
     private int mMaxButtonWidth;
     private int mMaxButtonHeight;
     private int mLabelsStyle;
     private int mLabelsPosition;
     private int mButtonsCount;
-    private TouchDelegateGroup mTouchDelegateGroup;
-    private OnFloatingActionsMenuUpdateListener mListener;
+    @Nullable private TouchDelegateGroup mTouchDelegateGroup;
+    @Nullable private OnFloatingActionsMenuUpdateListener mListener;
     private final Rect touchArea = new Rect(0, 0, 0, 0);
+    private float scrollYTranslation;
+    private float behaviorYTranslation;
 
     public FloatingActionsMenu(final Context context) {
         this(context, null);
     }
 
-    public FloatingActionsMenu(final Context context, final AttributeSet attrs) {
+    public FloatingActionsMenu(final Context context, @Nullable final AttributeSet attrs) {
         super(context, attrs);
         init(context, attrs);
     }
 
-    public FloatingActionsMenu(final Context context, final AttributeSet attrs, final int defStyle) {
+    public FloatingActionsMenu(final Context context, @Nullable final AttributeSet attrs, final int defStyle) {
         super(context, attrs, defStyle);
         init(context, attrs);
     }
 
-    private void init(final Context context, final AttributeSet attributeSet) {
+    private void init(final Context context, @Nullable final AttributeSet attributeSet) {
         mButtonSpacing = (int) (getResources().getDimension(R.dimen.fab_actions_spacing));
         mLabelsMargin = getResources().getDimensionPixelSize(R.dimen.fab_labels_margin);
         mLabelsVerticalOffset = getResources().getDimensionPixelSize(R.dimen.fab_shadow_offset);
@@ -103,6 +106,24 @@ public class FloatingActionsMenu extends ViewGroup {
         createAddButton(context);
     }
 
+    public float getScrollYTranslation() {
+        return scrollYTranslation;
+    }
+
+    public void setScrollYTranslation(final float scrollYTranslation) {
+        this.scrollYTranslation = scrollYTranslation;
+        setTranslationY(behaviorYTranslation + scrollYTranslation);
+    }
+
+    public float getBehaviorYTranslation() {
+        return behaviorYTranslation;
+    }
+
+    public void setBehaviorYTranslation(final float behaviorYTranslation) {
+        this.behaviorYTranslation = behaviorYTranslation;
+        setTranslationY(behaviorYTranslation + scrollYTranslation);
+    }
+
     public void setOnFloatingActionsMenuUpdateListener(final OnFloatingActionsMenuUpdateListener listener) {
         mListener = listener;
     }
@@ -112,7 +133,7 @@ public class FloatingActionsMenu extends ViewGroup {
     }
 
     private void createAddButton(final Context context) {
-        final RotatingDrawable rotatingDrawable = new RotatingDrawable(ResourcesCompat.getDrawable(context.getResources(), R.drawable.ic_action_add_inverse, context.getTheme()));
+        final RotatingDrawable rotatingDrawable = new RotatingDrawable(ResourcesCompat.getDrawable(context.getResources(), R.drawable.ic_action_add_white, context.getTheme()));
         mRotatingDrawable = rotatingDrawable;
 
         final TimeInterpolator interpolator = new OvershootInterpolator();
@@ -372,8 +393,10 @@ public class FloatingActionsMenu extends ViewGroup {
         }
     }
 
+    private static final boolean BROKEN_LABEL_STYLE = Build.VERSION.SDK_INT <= Build.VERSION_CODES.LOLLIPOP_MR1 && Build.BRAND.equals("ASUS");
+
     private void createLabels() {
-        final Context context = new ContextThemeWrapper(getContext(), mLabelsStyle);
+        final Context context = BROKEN_LABEL_STYLE ? getContext() : new ContextThemeWrapper(getContext(), mLabelsStyle);
 
         for (int i = 0; i < mButtonsCount; i++) {
             final FloatingActionButton button = (FloatingActionButton) getChildAt(i);
@@ -382,7 +405,8 @@ public class FloatingActionsMenu extends ViewGroup {
                 final String title = ((LabeledFloatingActionButton) button).getTitle();
 
                 final AppCompatTextView label = new AppCompatTextView(context);
-                label.setTextAppearance(context, mLabelsStyle);
+                if (!BROKEN_LABEL_STYLE)
+                    label.setTextAppearance(context, mLabelsStyle);
                 label.setText(title);
                 addView(label);
 
@@ -530,7 +554,7 @@ public class FloatingActionsMenu extends ViewGroup {
         }
 
         @Override
-        public void writeToParcel(@NonNull final Parcel out, final int flags) {
+        public void writeToParcel(final Parcel out, final int flags) {
             super.writeToParcel(out, flags);
             out.writeInt(mExpanded ? 1 : 0);
         }

app/src/main/java/com/wireguard/android/widget/fab/FloatingActionsMenuRecyclerViewScrollListener.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright © 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.android.widget.fab;
+
+import android.support.v7.widget.RecyclerView;
+
+public class FloatingActionsMenuRecyclerViewScrollListener extends RecyclerView.OnScrollListener {
+    private static final float SCALE_FACTOR = 1.5f;
+    private final FloatingActionsMenu menu;
+
+    public FloatingActionsMenuRecyclerViewScrollListener(final FloatingActionsMenu menu) {
+        this.menu = menu;
+    }
+
+    private static float bound(final float min, final float proposal, final float max) {
+        return Math.min(max, Math.max(min, proposal));
+    }
+
+    @Override
+    public void onScrolled(final RecyclerView recyclerView, final int dx, final int dy) {
+        super.onScrolled(recyclerView, dx, dy);
+        menu.setScrollYTranslation(bound(0, menu.getScrollYTranslation() + dy * SCALE_FACTOR, menu.getMeasuredHeight() - menu.getTranslationY()));
+    }
+}

app/src/main/java/com/wireguard/android/widget/fab/LabeledFloatingActionButton.java

@@ -8,6 +8,7 @@ package com.wireguard.android.widget.fab;
 
 import android.content.Context;
 import android.content.res.TypedArray;
+import android.support.annotation.Nullable;
 import android.support.design.widget.FloatingActionButton;
 import android.util.AttributeSet;
 import android.widget.TextView;
@@ -16,17 +17,17 @@ import com.wireguard.android.R;
 
 public class LabeledFloatingActionButton extends FloatingActionButton {
 
-    private final String title;
+    @Nullable private final String title;
 
     public LabeledFloatingActionButton(final Context context) {
         this(context, null);
     }
 
-    public LabeledFloatingActionButton(final Context context, final AttributeSet attrs) {
+    public LabeledFloatingActionButton(final Context context, @Nullable final AttributeSet attrs) {
         this(context, attrs, 0);
     }
 
-    public LabeledFloatingActionButton(final Context context, final AttributeSet attrs, final int defStyle) {
+    public LabeledFloatingActionButton(final Context context, @Nullable final AttributeSet attrs, final int defStyle) {
         super(context, attrs, defStyle);
 
         final TypedArray attr = context.obtainStyledAttributes(attrs, R.styleable.LabeledFloatingActionButton, 0, 0);
@@ -34,10 +35,12 @@ public class LabeledFloatingActionButton extends FloatingActionButton {
         attr.recycle();
     }
 
+    @Nullable
     TextView getLabelView() {
         return (TextView) getTag(R.id.fab_label);
     }
 
+    @Nullable
     public String getTitle() {
         return title;
     }

app/src/main/java/com/wireguard/android/widget/fab/TouchDelegateGroup.java

@@ -7,7 +7,7 @@
 package com.wireguard.android.widget.fab;
 
 import android.graphics.Rect;
-import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.view.MotionEvent;
 import android.view.TouchDelegate;
 import android.view.View;
@@ -18,14 +18,14 @@ import java.util.Collection;
 public class TouchDelegateGroup extends TouchDelegate {
     private static final Rect USELESS_HACKY_RECT = new Rect();
     private final Collection<TouchDelegate> mTouchDelegates = new ArrayList<>();
-    private TouchDelegate mCurrentTouchDelegate;
+    @Nullable private TouchDelegate mCurrentTouchDelegate;
     private boolean mEnabled;
 
     public TouchDelegateGroup(final View uselessHackyView) {
         super(USELESS_HACKY_RECT, uselessHackyView);
     }
 
-    public void addTouchDelegate(@NonNull final TouchDelegate touchDelegate) {
+    public void addTouchDelegate(final TouchDelegate touchDelegate) {
         mTouchDelegates.add(touchDelegate);
     }
 
@@ -42,7 +42,7 @@ public class TouchDelegateGroup extends TouchDelegate {
     }
 
     @Override
-    public boolean onTouchEvent(@NonNull final MotionEvent event) {
+    public boolean onTouchEvent(final MotionEvent event) {
         if (!mEnabled)
             return false;
 

app/src/main/java/com/wireguard/config/Attribute.java

@@ -6,10 +6,11 @@
 
 package com.wireguard.config;
 
+import android.annotation.SuppressLint;
+import android.support.annotation.Nullable;
 import android.text.TextUtils;
 
 import java.util.HashMap;
-import java.util.Locale;
 import java.util.Map;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -55,33 +56,38 @@ public enum Attribute {
         return TextUtils.join(", ", iterable);
     }
 
+    @Nullable
     public static Attribute match(final CharSequence line) {
         return KEY_MAP.get(SEPARATOR_PATTERN.split(line)[0].toLowerCase());
     }
 
-    public static String[] stringToList(final String string) {
+    public static String[] stringToList(@Nullable final String string) {
         if (TextUtils.isEmpty(string))
             return EMPTY_LIST;
         return LIST_SEPARATOR_PATTERN.split(string.trim());
     }
 
-    public String composeWith(final Object value) {
+    @SuppressLint("DefaultLocale")
+    public String composeWith(@Nullable final Object value) {
         return String.format("%s = %s%n", token, value);
     }
 
+    @SuppressLint("DefaultLocale")
     public String composeWith(final int value) {
-        return String.format(Locale.getDefault(), "%s = %d%n", token, value);
+        return String.format("%s = %d%n", token, value);
     }
 
     public <T> String composeWith(final Iterable<T> value) {
         return String.format("%s = %s%n", token, iterableToString(value));
     }
 
+    @Nullable
     public String parse(final CharSequence line) {
         final Matcher matcher = pattern.matcher(line);
         return matcher.matches() ? matcher.group(1) : null;
     }
 
+    @Nullable
     public String[] parseList(final CharSequence line) {
         final Matcher matcher = pattern.matcher(line);
         return matcher.matches() ? stringToList(matcher.group(1)) : null;

app/src/main/java/com/wireguard/config/Config.java

@@ -6,19 +6,24 @@
 
 package com.wireguard.config;
 
+import android.content.Context;
 import android.databinding.BaseObservable;
 import android.databinding.Bindable;
 import android.databinding.ObservableArrayList;
 import android.databinding.ObservableList;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.support.annotation.Nullable;
 
 import com.android.databinding.library.baseAdapters.BR;
+import com.wireguard.android.Application;
+import com.wireguard.android.R;
 
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.io.StringReader;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
@@ -31,12 +36,17 @@ public class Config {
     private final Interface interfaceSection = new Interface();
     private List<Peer> peers = new ArrayList<>();
 
+    public static Config from(final String string) throws IOException {
+        return from(new BufferedReader(new StringReader(string)));
+    }
+
     public static Config from(final InputStream stream) throws IOException {
         return from(new BufferedReader(new InputStreamReader(stream, StandardCharsets.UTF_8)));
     }
 
     public static Config from(final BufferedReader reader) throws IOException {
         final Config config = new Config();
+        final Context context = Application.get();
         Peer currentPeer = null;
         String line;
         boolean inInterfaceSection = false;
@@ -59,11 +69,11 @@ public class Config {
             } else if (currentPeer != null) {
                 currentPeer.parse(line);
             } else {
-                throw new IllegalArgumentException("Invalid configuration line: " + line);
+                throw new IllegalArgumentException(context.getString(R.string.tunnel_error_invalid_config_line, line));
             }
         }
         if (!inInterfaceSection && currentPeer == null) {
-            throw new IllegalArgumentException("Could not find any config information");
+            throw new IllegalArgumentException(context.getString(R.string.tunnel_error_no_config_information));
         }
         return config;
     }
@@ -96,13 +106,19 @@ public class Config {
                 return new Observable[size];
             }
         };
-        private String name;
-        private Interface.Observable observableInterface;
-        private ObservableList<Peer.Observable> observablePeers;
+        @Nullable private String name;
+        private final Interface.Observable observableInterface;
+        private final ObservableList<Peer.Observable> observablePeers;
 
-        public Observable(final Config parent, final String name) {
+        public Observable(@Nullable final Config parent, @Nullable final String name) {
             this.name = name;
-            loadData(parent);
+
+            observableInterface = new Interface.Observable(parent == null ? null : parent.interfaceSection);
+            observablePeers = new ObservableArrayList<>();
+            if (parent != null) {
+                for (final Peer peer : parent.getPeers())
+                    observablePeers.add(new Peer.Observable(peer));
+            }
         }
 
         private Observable(final Parcel in) {
@@ -144,15 +160,6 @@ public class Config {
             return observablePeers;
         }
 
-        protected void loadData(final Config parent) {
-            observableInterface = new Interface.Observable(parent == null ? null : parent.interfaceSection);
-            observablePeers = new ObservableArrayList<>();
-            if (parent != null) {
-                for (final Peer peer : parent.getPeers())
-                    observablePeers.add(new Peer.Observable(peer));
-            }
-        }
-
         public void setName(final String name) {
             this.name = name;
             notifyPropertyChanged(BR.name);

app/src/main/java/com/wireguard/config/InetAddresses.java

@@ -6,9 +6,11 @@
 
 package com.wireguard.config;
 
-import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 
+import com.wireguard.android.Application;
+import com.wireguard.android.R;
+
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.net.InetAddress;
@@ -29,14 +31,13 @@ public final class InetAddresses {
         // Prevent instantiation.
     }
 
-    @NonNull
     public static InetAddress parse(@Nullable final String address) {
         if (address == null || address.isEmpty())
-            throw new IllegalArgumentException("Empty address");
+            throw new IllegalArgumentException(Application.get().getString(R.string.tunnel_error_empty_inetaddress));
         try {
             return (InetAddress) PARSER_METHOD.invoke(null, address);
         } catch (final IllegalAccessException | InvocationTargetException e) {
-            throw new RuntimeException(e);
+            throw new RuntimeException(e.getCause() == null ? e : e.getCause());
         }
     }
 }

app/src/main/java/com/wireguard/config/InetNetwork.java

@@ -6,8 +6,6 @@
 
 package com.wireguard.config;
 
-import android.support.annotation.NonNull;
-
 import java.net.Inet4Address;
 import java.net.InetAddress;
 import java.util.Objects;
@@ -16,7 +14,7 @@ public class InetNetwork {
     private final InetAddress address;
     private final int mask;
 
-    public InetNetwork(@NonNull final String input) {
+    public InetNetwork(final String input) {
         final int slash = input.lastIndexOf('/');
         final int rawMask;
         final String rawAddress;
@@ -40,7 +38,6 @@ public class InetNetwork {
         return Objects.equals(address, other.address) && mask == other.mask;
     }
 
-    @NonNull
     public InetAddress getAddress() {
         return address;
     }

app/src/main/java/com/wireguard/config/Interface.java

@@ -6,12 +6,16 @@
 
 package com.wireguard.config;
 
+import android.content.Context;
 import android.databinding.BaseObservable;
 import android.databinding.Bindable;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.support.annotation.Nullable;
 
+import com.wireguard.android.Application;
 import com.wireguard.android.BR;
+import com.wireguard.android.R;
 import com.wireguard.crypto.Keypair;
 
 import java.net.InetAddress;
@@ -27,9 +31,10 @@ public class Interface {
     private final List<InetNetwork> addressList;
     private final List<InetAddress> dnsList;
     private final List<String> excludedApplications;
-    private Keypair keypair;
+    @Nullable private Keypair keypair;
     private int listenPort;
     private int mtu;
+    private final Context context = Application.get();
 
     public Interface() {
         addressList = new ArrayList<>();
@@ -37,17 +42,17 @@ public class Interface {
         excludedApplications = new ArrayList<>();
     }
 
-    private void addAddresses(final String[] addresses) {
+    private void addAddresses(@Nullable final String[] addresses) {
         if (addresses != null && addresses.length > 0) {
             for (final String addr : addresses) {
                 if (addr.isEmpty())
-                    throw new IllegalArgumentException("Address is empty");
+                    throw new IllegalArgumentException(context.getString(R.string.tunnel_error_empty_interface_address));
                 addressList.add(new InetNetwork(addr));
             }
         }
     }
 
-    private void addDnses(final String[] dnses) {
+    private void addDnses(@Nullable final String[] dnses) {
         if (dnses != null && dnses.length > 0) {
             for (final String dns : dnses) {
                 dnsList.add(InetAddresses.parse(dns));
@@ -55,12 +60,13 @@ public class Interface {
         }
     }
 
-    private void addExcludedApplications(final String[] applications) {
+    private void addExcludedApplications(@Nullable final String[] applications) {
         if (applications != null && applications.length > 0) {
             excludedApplications.addAll(Arrays.asList(applications));
         }
     }
 
+    @Nullable
     private String getAddressString() {
         if (addressList.isEmpty())
             return null;
@@ -71,6 +77,7 @@ public class Interface {
         return addressList.toArray(new InetNetwork[addressList.size()]);
     }
 
+    @Nullable
     private String getDnsString() {
         if (dnsList.isEmpty())
             return null;
@@ -88,6 +95,7 @@ public class Interface {
         return dnsList.toArray(new InetAddress[dnsList.size()]);
     }
 
+    @Nullable
     private String getExcludedApplicationsString() {
         if (excludedApplications.isEmpty())
             return null;
@@ -102,6 +110,7 @@ public class Interface {
         return listenPort;
     }
 
+    @Nullable
     private String getListenPortString() {
         if (listenPort == 0)
             return null;
@@ -112,18 +121,21 @@ public class Interface {
         return mtu;
     }
 
+    @Nullable
     private String getMtuString() {
         if (mtu == 0)
             return null;
         return Integer.toString(mtu);
     }
 
+    @Nullable
     public String getPrivateKey() {
         if (keypair == null)
             return null;
         return keypair.getPrivateKey();
     }
 
+    @Nullable
     public String getPublicKey() {
         if (keypair == null)
             return null;
@@ -132,6 +144,8 @@ public class Interface {
 
     public void parse(final String line) {
         final Attribute key = Attribute.match(line);
+        if (key == null)
+            throw new IllegalArgumentException(String.format(context.getString(R.string.tunnel_error_interface_parse_failed), line));
         switch (key) {
             case ADDRESS:
                 addAddresses(key.parseList(line));
@@ -156,17 +170,17 @@ public class Interface {
         }
     }
 
-    private void setAddressString(final String addressString) {
+    private void setAddressString(@Nullable final String addressString) {
         addressList.clear();
         addAddresses(Attribute.stringToList(addressString));
     }
 
-    private void setDnsString(final String dnsString) {
+    private void setDnsString(@Nullable final String dnsString) {
         dnsList.clear();
         addDnses(Attribute.stringToList(dnsString));
     }
 
-    private void setExcludedApplicationsString(final String applicationsString) {
+    private void setExcludedApplicationsString(@Nullable final String applicationsString) {
         excludedApplications.clear();
         addExcludedApplications(Attribute.stringToList(applicationsString));
     }
@@ -175,7 +189,7 @@ public class Interface {
         this.listenPort = listenPort;
     }
 
-    private void setListenPortString(final String port) {
+    private void setListenPortString(@Nullable final String port) {
         if (port != null && !port.isEmpty())
             setListenPort(Integer.parseInt(port, 10));
         else
@@ -186,14 +200,14 @@ public class Interface {
         this.mtu = mtu;
     }
 
-    private void setMtuString(final String mtu) {
+    private void setMtuString(@Nullable final String mtu) {
         if (mtu != null && !mtu.isEmpty())
             setMtu(Integer.parseInt(mtu, 10));
         else
             setMtu(0);
     }
 
-    private void setPrivateKey(String privateKey) {
+    private void setPrivateKey(@Nullable String privateKey) {
         if (privateKey != null && privateKey.isEmpty())
             privateKey = null;
         keypair = privateKey == null ? null : new Keypair(privateKey);
@@ -229,15 +243,15 @@ public class Interface {
                 return new Observable[size];
             }
         };
-        private String addresses;
-        private String dnses;
-        private String excludedApplications;
-        private String listenPort;
-        private String mtu;
-        private String privateKey;
-        private String publicKey;
+        @Nullable private String addresses;
+        @Nullable private String dnses;
+        @Nullable private String excludedApplications;
+        @Nullable private String listenPort;
+        @Nullable private String mtu;
+        @Nullable private String privateKey;
+        @Nullable private String publicKey;
 
-        public Observable(final Interface parent) {
+        public Observable(@Nullable final Interface parent) {
             if (parent != null)
                 loadData(parent);
         }
@@ -276,16 +290,19 @@ public class Interface {
             notifyPropertyChanged(BR.publicKey);
         }
 
+        @Nullable
         @Bindable
         public String getAddresses() {
             return addresses;
         }
 
+        @Nullable
         @Bindable
         public String getDnses() {
             return dnses;
         }
 
+        @Nullable
         @Bindable
         public String getExcludedApplications() {
             return excludedApplications;
@@ -296,27 +313,31 @@ public class Interface {
             return Attribute.stringToList(excludedApplications).length;
         }
 
+        @Nullable
         @Bindable
         public String getListenPort() {
             return listenPort;
         }
 
+        @Nullable
         @Bindable
         public String getMtu() {
             return mtu;
         }
 
+        @Nullable
         @Bindable
         public String getPrivateKey() {
             return privateKey;
         }
 
+        @Nullable
         @Bindable
         public String getPublicKey() {
             return publicKey;
         }
 
-        protected void loadData(final Interface parent) {
+        private void loadData(final Interface parent) {
             addresses = parent.getAddressString();
             dnses = parent.getDnsString();
             excludedApplications = parent.getExcludedApplicationsString();

app/src/main/java/com/wireguard/config/Peer.java

@@ -6,12 +6,17 @@
 
 package com.wireguard.config;
 
+import android.annotation.SuppressLint;
+import android.content.Context;
 import android.databinding.BaseObservable;
 import android.databinding.Bindable;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.support.annotation.Nullable;
 
 import com.android.databinding.library.baseAdapters.BR;
+import com.wireguard.android.Application;
+import com.wireguard.android.R;
 import com.wireguard.crypto.KeyEncoding;
 
 import java.net.Inet6Address;
@@ -24,7 +29,6 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
-import java.util.Locale;
 
 import java9.lang.Iterables;
 
@@ -34,16 +38,17 @@ import java9.lang.Iterables;
 
 public class Peer {
     private final List<InetNetwork> allowedIPsList;
-    private InetSocketAddress endpoint;
+    @Nullable private InetSocketAddress endpoint;
     private int persistentKeepalive;
-    private String preSharedKey;
-    private String publicKey;
+    @Nullable private String preSharedKey;
+    @Nullable private String publicKey;
+    private final Context context = Application.get();
 
     public Peer() {
         allowedIPsList = new ArrayList<>();
     }
 
-    private void addAllowedIPs(final String[] allowedIPs) {
+    private void addAllowedIPs(@Nullable final String[] allowedIPs) {
         if (allowedIPs != null && allowedIPs.length > 0) {
             for (final String allowedIP : allowedIPs) {
                 allowedIPsList.add(new InetNetwork(allowedIP));
@@ -55,40 +60,51 @@ public class Peer {
         return allowedIPsList.toArray(new InetNetwork[allowedIPsList.size()]);
     }
 
+    @Nullable
     private String getAllowedIPsString() {
         if (allowedIPsList.isEmpty())
             return null;
         return Attribute.iterableToString(allowedIPsList);
     }
 
+    @Nullable
     public InetSocketAddress getEndpoint() {
         return endpoint;
     }
 
+    @SuppressLint("DefaultLocale")
+    @Nullable
     private String getEndpointString() {
         if (endpoint == null)
             return null;
-        return String.format(Locale.getDefault(), "%s:%d", endpoint.getHostString(), endpoint.getPort());
+        if (endpoint.getHostString().contains(":") && !endpoint.getHostString().contains("["))
+            return String.format("[%s]:%d", endpoint.getHostString(), endpoint.getPort());
+        else
+            return String.format("%s:%d", endpoint.getHostString(), endpoint.getPort());
     }
 
     public int getPersistentKeepalive() {
         return persistentKeepalive;
     }
 
+    @Nullable
     private String getPersistentKeepaliveString() {
         if (persistentKeepalive == 0)
             return null;
         return Integer.valueOf(persistentKeepalive).toString();
     }
 
+    @Nullable
     public String getPreSharedKey() {
         return preSharedKey;
     }
 
+    @Nullable
     public String getPublicKey() {
         return publicKey;
     }
 
+    @SuppressLint("DefaultLocale")
     public String getResolvedEndpointString() throws UnknownHostException {
         if (endpoint == null)
             throw new UnknownHostException("{empty}");
@@ -97,18 +113,18 @@ public class Peer {
         if (endpoint.isUnresolved())
             throw new UnknownHostException(endpoint.getHostString());
         if (endpoint.getAddress() instanceof Inet6Address)
-            return String.format(Locale.getDefault(),
-                    "[%s]:%d",
+            return String.format("[%s]:%d",
                     endpoint.getAddress().getHostAddress(),
                     endpoint.getPort());
-        return String.format(Locale.getDefault(),
-                "%s:%d",
+        return String.format("%s:%d",
                 endpoint.getAddress().getHostAddress(),
                 endpoint.getPort());
     }
 
     public void parse(final String line) {
         final Attribute key = Attribute.match(line);
+        if (key == null)
+            throw new IllegalArgumentException(context.getString(R.string.tunnel_error_interface_parse_failed, line));
         switch (key) {
             case ALLOWED_IPS:
                 addAllowedIPs(key.parseList(line));
@@ -130,20 +146,20 @@ public class Peer {
         }
     }
 
-    private void setAllowedIPsString(final String allowedIPsString) {
+    private void setAllowedIPsString(@Nullable final String allowedIPsString) {
         allowedIPsList.clear();
         addAllowedIPs(Attribute.stringToList(allowedIPsString));
     }
 
-    private void setEndpoint(final InetSocketAddress endpoint) {
+    private void setEndpoint(@Nullable final InetSocketAddress endpoint) {
         this.endpoint = endpoint;
     }
 
-    private void setEndpointString(final String endpoint) {
+    private void setEndpointString(@Nullable final String endpoint) {
         if (endpoint != null && !endpoint.isEmpty()) {
             final InetSocketAddress constructedEndpoint;
             if (endpoint.indexOf('/') != -1 || endpoint.indexOf('?') != -1 || endpoint.indexOf('#') != -1)
-                throw new IllegalArgumentException("Forbidden characters in endpoint");
+                throw new IllegalArgumentException(context.getString(R.string.tunnel_error_forbidden_endpoint_chars));
             final URI uri;
             try {
                 uri = new URI("wg://" + endpoint);
@@ -160,14 +176,14 @@ public class Peer {
         this.persistentKeepalive = persistentKeepalive;
     }
 
-    private void setPersistentKeepaliveString(final String persistentKeepalive) {
+    private void setPersistentKeepaliveString(@Nullable final String persistentKeepalive) {
         if (persistentKeepalive != null && !persistentKeepalive.isEmpty())
             setPersistentKeepalive(Integer.parseInt(persistentKeepalive, 10));
         else
             setPersistentKeepalive(0);
     }
 
-    private void setPreSharedKey(String preSharedKey) {
+    private void setPreSharedKey(@Nullable String preSharedKey) {
         if (preSharedKey != null && preSharedKey.isEmpty())
             preSharedKey = null;
         if (preSharedKey != null)
@@ -175,7 +191,7 @@ public class Peer {
         this.preSharedKey = preSharedKey;
     }
 
-    private void setPublicKey(String publicKey) {
+    private void setPublicKey(@Nullable String publicKey) {
         if (publicKey != null && publicKey.isEmpty())
             publicKey = null;
         if (publicKey != null)
@@ -211,12 +227,12 @@ public class Peer {
                 return new Observable[size];
             }
         };
-        private String allowedIPs;
-        private String endpoint;
-        private String persistentKeepalive;
-        private String preSharedKey;
-        private String publicKey;
-        private List<String> interfaceDNSRoutes;
+        @Nullable private String allowedIPs;
+        @Nullable private String endpoint;
+        @Nullable private String persistentKeepalive;
+        @Nullable private String preSharedKey;
+        @Nullable private String publicKey;
+        private final List<String> interfaceDNSRoutes = new ArrayList<>();
         private int numSiblings;
 
         public Observable(final Peer parent) {
@@ -230,7 +246,6 @@ public class Peer {
             preSharedKey = in.readString();
             publicKey = in.readString();
             numSiblings = in.readInt();
-            interfaceDNSRoutes = new ArrayList<>();
             in.readStringList(interfaceDNSRoutes);
         }
 
@@ -245,7 +260,7 @@ public class Peer {
             parent.setPreSharedKey(preSharedKey);
             parent.setPublicKey(publicKey);
             if (parent.getPublicKey() == null)
-                throw new IllegalArgumentException("Peer public key may not be empty");
+                throw new IllegalArgumentException(Application.get().getString(R.string.tunnel_error_empty_peer_public_key));
             loadData(parent);
             notifyChange();
         }
@@ -284,38 +299,37 @@ public class Peer {
             return numSiblings == 0 && Arrays.asList(Attribute.stringToList(allowedIPs)).containsAll(DEFAULT_ROUTE_MOD_RFC1918_V4);
         }
 
-        @Bindable
+        @Bindable @Nullable
         public String getAllowedIPs() {
             return allowedIPs;
         }
 
-        @Bindable
+        @Bindable @Nullable
         public String getEndpoint() {
             return endpoint;
         }
 
-        @Bindable
+        @Bindable @Nullable
         public String getPersistentKeepalive() {
             return persistentKeepalive;
         }
 
-        @Bindable
+        @Bindable @Nullable
         public String getPreSharedKey() {
             return preSharedKey;
         }
 
-        @Bindable
+        @Bindable @Nullable
         public String getPublicKey() {
             return publicKey;
         }
 
-        protected void loadData(final Peer parent) {
+        private void loadData(final Peer parent) {
             allowedIPs = parent.getAllowedIPsString();
             endpoint = parent.getEndpointString();
             persistentKeepalive = parent.getPersistentKeepaliveString();
             preSharedKey = parent.getPreSharedKey();
             publicKey = parent.getPublicKey();
-            interfaceDNSRoutes = new ArrayList<>();
         }
 
         public void setAllowedIPs(final String allowedIPs) {
@@ -345,7 +359,7 @@ public class Peer {
             notifyPropertyChanged(BR.publicKey);
         }
 
-        public void setInterfaceDNSRoutes(final String dnsServers) {
+        public void setInterfaceDNSRoutes(@Nullable final String dnsServers) {
             final Collection<String> ips = new HashSet<>(Arrays.asList(Attribute.stringToList(allowedIPs)));
             final boolean modifyAllowedIPs = ips.containsAll(DEFAULT_ROUTE_MOD_RFC1918_V4);
 

app/src/main/java/com/wireguard/crypto/Curve25519.java

@@ -5,6 +5,8 @@
 
 package com.wireguard.crypto;
 
+import android.support.annotation.Nullable;
+
 import java.util.Arrays;
 
 /**
@@ -93,7 +95,7 @@ public final class Curve25519 {
      *                   if the base point of the curve should be used.
      */
     public static void eval(final byte[] result, final int offset,
-                            final byte[] privateKey, final byte[] publicKey) {
+                            final byte[] privateKey, @Nullable final byte[] publicKey) {
         final Curve25519 state = new Curve25519();
         try {
             // Unpack the public key value.  If null, use 9 as the base point.

app/src/main/java/com/wireguard/crypto/KeyEncoding.java

@@ -5,6 +5,9 @@
 
 package com.wireguard.crypto;
 
+import com.wireguard.android.Application;
+import com.wireguard.android.R;
+
 /**
  * This is a specialized constant-time base64 and hex implementation that resists side-channel attacks.
  */
@@ -15,11 +18,11 @@ public final class KeyEncoding {
     public static final int KEY_LENGTH_BASE64 = 44;
     public static final int KEY_LENGTH_HEX = 64;
     private static final String KEY_LENGTH_BASE64_EXCEPTION_MESSAGE =
-            "WireGuard base64 keys must be 44 characters encoding 32 bytes";
+            Application.get().getString(R.string.key_length_base64_exception_message);
     private static final String KEY_LENGTH_EXCEPTION_MESSAGE =
-            "WireGuard keys must be 32 bytes";
+            Application.get().getString(R.string.key_length_exception_message);
     private static final String KEY_LENGTH_HEX_EXCEPTION_MESSAGE =
-            "WireGuard hex keys must be 64 characters encoding 32 bytes";
+            Application.get().getString(R.string.key_length_hex_exception_message);
 
     private KeyEncoding() {
         // Prevent instantiation.

app/src/main/java/com/wireguard/util/KeyedList.java

@@ -5,6 +5,8 @@
 
 package com.wireguard.util;
 
+import android.support.annotation.Nullable;
+
 import java.util.Collection;
 import java.util.List;
 
@@ -18,8 +20,10 @@ public interface KeyedList<K, E extends Keyed<? extends K>> extends List<E> {
 
     boolean containsKey(K key);
 
+    @Nullable
     E get(K key);
 
+    @Nullable
     E getLast(K key);
 
     int indexOfKey(K key);

app/src/main/java/com/wireguard/util/NonNullForAll.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright © 2018 Eric Kuck <eric@bluelinelabs.com>.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.util;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+import javax.annotation.Nonnull;
+import javax.annotation.meta.TypeQualifierDefault;
+
+/**
+ * This annotation can be applied to a package, class or method to indicate that all
+ * class fields and method parameters and return values in that element are nonnull
+ * by default unless overridden.
+ */
+@Documented
+@Nonnull
+@TypeQualifierDefault({ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER})
+@Retention(RetentionPolicy.RUNTIME)
+public @interface NonNullForAll { }

app/src/main/java/com/wireguard/util/SortedKeyedList.java

@@ -5,6 +5,8 @@
 
 package com.wireguard.util;
 
+import android.support.annotation.Nullable;
+
 import java.util.Collection;
 import java.util.Comparator;
 import java.util.Set;
@@ -17,10 +19,12 @@ import java.util.Set;
 public interface SortedKeyedList<K, E extends Keyed<? extends K>> extends KeyedList<K, E> {
     Comparator<? super K> comparator();
 
+    @Nullable
     K firstKey();
 
     Set<K> keySet();
 
+    @Nullable
     K lastKey();
 
     Collection<E> values();

app/src/main/res/drawable/ic_action_add_white.xml

@@ -4,6 +4,6 @@
     android:viewportHeight="24.0"
     android:viewportWidth="24.0">
     <path
-        android:fillColor="?android:attr/colorBackground"
+        android:fillColor="#ffffff"
         android:pathData="M19,13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z" />
 </vector>

app/src/main/res/drawable/ic_action_edit_white.xml

@@ -4,6 +4,6 @@
     android:viewportHeight="24"
     android:viewportWidth="24">
     <path
-        android:fillColor="?android:attr/colorBackground"
+        android:fillColor="#ffffff"
         android:pathData="M3,17.25V21h3.75L17.81,9.94l-3.75,-3.75L3,17.25zM20.71,7.04c0.39,-0.39 0.39,-1.02 0,-1.41l-2.34,-2.34c-0.39,-0.39 -1.02,-0.39 -1.41,0l-1.83,1.83 3.75,3.75 1.83,-1.83z" />
 </vector>

app/src/main/res/drawable/ic_action_open_white.xml

@@ -4,6 +4,6 @@
     android:viewportHeight="24"
     android:viewportWidth="24">
     <path
-        android:fillColor="?android:attr/colorBackground"
+        android:fillColor="#ffffff"
         android:pathData="M6,2c-1.1,0 -1.99,0.9 -1.99,2L4,20c0,1.1 0.89,2 1.99,2L18,22c1.1,0 2,-0.9 2,-2L20,8l-6,-6L6,2zM13,9L13,3.5L18.5,9L13,9z" />
 </vector>

app/src/main/res/drawable/ic_action_scan_qr_code_white.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportHeight="24"
+    android:viewportWidth="24">
+    <path
+        android:fillColor="#ffffff"
+        android:pathData="M4,4H10V10H4V4M20,4V10H14V4H20M14,15H16V13H14V11H16V13H18V11H20V13H18V15H20V18H18V20H16V18H13V20H11V16H14V15M16,15V18H18V15H16M4,20V14H10V20H4M6,6V8H8V6H6M16,6V8H18V6H16M6,16V18H8V16H6M4,11H6V13H4V11M9,11H13V15H11V13H9V11M11,6H13V10H11V6M2,2V6H0V2A2,2 0 0,1 2,0H6V2H2M22,0A2,2 0 0,1 24,2V6H22V2H18V0H22M2,18V22H6V24H2A2,2 0 0,1 0,22V18H2M22,22V18H24V22A2,2 0 0,1 22,24H18V22H22Z" />
+</vector>

app/src/main/res/drawable/list_item_background.xml

@@ -1,5 +1,15 @@
 <?xml version="1.0" encoding="utf-8"?>
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <item android:drawable="@color/list_item_activated" android:state_activated="true" /> <!-- TODO(msf): themeify this -->
-    <item android:drawable="@android:color/transparent" /> <!-- TODO(msf): themeify this -->
-</selector>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+    <item>
+        <selector>
+            <item app:state_multiselected="true" android:state_activated="true">
+                <color android:color="?attr/colorControlActivated" />
+            </item>
+            <item app:state_multiselected="false" android:state_activated="true">
+                <color android:color="?attr/colorControlHighlight" />
+            </item>
+        </selector>
+    </item>
+    <item android:drawable="?attr/selectableItemBackground" />
+</layer-list>

app/src/main/res/drawable/list_item_background_anim.xml

@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<ripple xmlns:android="http://schemas.android.com/apk/res/android"
-    android:color="@color/list_item_ripple"> <!-- TODO(msf): themeify this -->
-    <item android:drawable="@drawable/list_item_background" />
-    <item android:id="@android:id/mask" android:drawable="@android:color/white" />
-</ripple>

app/src/main/res/layout-sw600dp/main_activity.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/master_detail_wrapper"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:baselineAligned="false"
+    android:divider="?attr/dividerHorizontal"
+    android:orientation="horizontal"
+    android:showDividers="middle"
+    tools:context=".activity.MainActivity">
+
+    <fragment
+        android:name="com.wireguard.android.fragment.TunnelListFragment"
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="2"
+        android:tag="LIST" />
+
+    <FrameLayout
+        android:id="@+id/detail_container"
+        android:layout_width="0dp"
+        android:layout_height="match_parent"
+        android:layout_weight="3" />
+</LinearLayout>

app/src/main/res/layout/app_list_item.xml

@@ -22,7 +22,7 @@
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:background="@drawable/list_item_background_anim"
+        android:background="@drawable/list_item_background"
         android:padding="16dp"
         android:orientation="horizontal"
         android:gravity="center_vertical"

app/src/main/res/layout/config_naming_dialog_fragment.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <data>
+        <import type="com.wireguard.android.widget.NameInputFilter" />
+    </data>
+
+    <FrameLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:padding="16dp">
+
+        <android.support.design.widget.TextInputLayout
+            android:id="@+id/tunnel_name_text_layout"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content">
+
+            <EditText
+                android:id="@+id/tunnel_name_text"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:hint="@string/tunnel_name"
+                android:inputType="textNoSuggestions|textVisiblePassword"
+                app:filter="@{NameInputFilter.newInstance()}" />
+
+        </android.support.design.widget.TextInputLayout>
+
+    </FrameLayout>
+
+
+</layout>

app/src/main/res/layout/main_activity.xml

@@ -1,7 +1,19 @@
 <?xml version="1.0" encoding="utf-8"?>
 <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
-    android:id="@+id/master_fragment"
+    android:id="@+id/master_detail_wrapper"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    tools:ignore="MergeRootFrame" />
+    tools:context=".activity.MainActivity">
+
+    <fragment
+        android:name="com.wireguard.android.fragment.TunnelListFragment"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:tag="LIST" />
+
+    <FrameLayout
+        android:id="@+id/detail_container"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent" />
+</FrameLayout>

app/src/main/res/layout/tunnel_detail_fragment.xml

@@ -55,7 +55,6 @@
                         android:layout_height="wrap_content"
                         android:layout_alignParentStart="true"
                         android:layout_alignParentTop="true"
-                        android:layout_toStartOf="@+id/tunnel_switch"
                         android:text="@string/interface_title" />
 
                     <com.wireguard.android.widget.ToggleSwitch

app/src/main/res/layout/tunnel_editor_fragment.xml

@@ -120,7 +120,7 @@
 
                         <TextView
                             android:id="@+id/public_key_text"
-                            style="?android:attr/editTextStyle"
+                            style="?attr/editTextStyle"
                             android:layout_width="match_parent"
                             android:layout_height="wrap_content"
                             android:layout_below="@+id/public_key_label"

app/src/main/res/layout/tunnel_list_fragment.xml

@@ -30,20 +30,65 @@
             android:id="@+id/tunnel_list"
             android:layout_width="match_parent"
             android:layout_height="match_parent"
+            android:paddingBottom="@{@dimen/design_fab_size_normal * 1.1f}"
+            android:clipToPadding="false"
             android:choiceMode="multipleChoiceModal"
+            android:visibility="@{tunnels.size() > 0 ? android.view.View.VISIBLE : android.view.View.GONE}"
             app:items="@{tunnels}"
             app:layout="@{@layout/tunnel_list_item}"
             app:configurationHandler="@{rowConfigurationHandler}" />
 
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:visibility="@{tunnels.size() == 0 ? android.view.View.VISIBLE : android.view.View.GONE}"
+            android:layout_gravity="center">
+            <android.support.v7.widget.AppCompatImageView
+                android:id="@+id/logo_placeholder"
+                android:layout_width="140dp"
+                android:layout_height="140dp"
+                android:layout_gravity="center"
+                android:alpha="0.3333333"
+                android:layout_marginTop="-70dp"
+                android:layout_marginBottom="20dp"
+                android:src="@mipmap/ic_launcher" />
+            <TextView
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_gravity="center"
+                android:textSize="20sp"
+                android:text="@string/tunnel_list_placeholder" />
+        </LinearLayout>
+
         <com.wireguard.android.widget.fab.FloatingActionsMenu
             android:id="@+id/create_menu"
+            android:clipChildren="false"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_gravity="bottom|end"
-            android:layout_margin="16dp"
+            android:layout_margin="@dimen/fab_margin"
             app:fab_labelStyle="@style/fab_label"
-            android:clipChildren="false"
-            app:fab_labelsPosition="left" >
+            app:fab_labelsPosition="@integer/label_position"
+            app:layout_behavior="com.wireguard.android.widget.fab.FloatingActionButtonBehavior" >
+
+            <com.wireguard.android.widget.fab.LabeledFloatingActionButton
+                android:id="@+id/create_from_file"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:onClick="@{fragment::onRequestImportConfig}"
+                app:srcCompat="@drawable/ic_action_open_white"
+                app:fabSize="mini"
+                app:fab_title="@string/create_from_file" />
+
+            <com.wireguard.android.widget.fab.LabeledFloatingActionButton
+                android:id="@+id/scan_qr_code"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:onClick="@{fragment::onRequestScanQRCode}"
+                app:srcCompat="@drawable/ic_action_scan_qr_code_white"
+                app:fabSize="mini"
+                app:fab_title="@string/create_from_qrcode" />
 
             <com.wireguard.android.widget.fab.LabeledFloatingActionButton
                 android:id="@+id/create_empty"
@@ -51,17 +96,9 @@
                 android:layout_height="wrap_content"
                 android:onClick="@{fragment::onRequestCreateConfig}"
                 app:fabSize="mini"
-                app:srcCompat="@drawable/ic_action_edit_inverse"
+                app:srcCompat="@drawable/ic_action_edit_white"
                 app:fab_title="@string/create_empty" />
-
-            <com.wireguard.android.widget.fab.LabeledFloatingActionButton
-                android:id="@+id/create_from_file"
-                android:layout_width="wrap_content"
-                android:layout_height="wrap_content"
-                android:onClick="@{fragment::onRequestImportConfig}"
-                app:srcCompat="@drawable/ic_action_open_inverse"
-                app:fabSize="mini"
-                app:fab_title="@string/create_from_file" />
         </com.wireguard.android.widget.fab.FloatingActionsMenu>
+
     </android.support.design.widget.CoordinatorLayout>
 </layout>

app/src/main/res/layout/tunnel_list_item.xml

@@ -25,10 +25,10 @@
             type="com.wireguard.android.fragment.TunnelListFragment" />
     </data>
 
-    <RelativeLayout
+    <com.wireguard.android.widget.MultiselectableRelativeLayout
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:background="@drawable/list_item_background_anim"
+        android:background="@drawable/list_item_background"
         android:descendantFocusability="blocksDescendants"
         android:padding="16dp">
 
@@ -39,7 +39,6 @@
             android:layout_height="wrap_content"
             android:layout_alignParentStart="true"
             android:layout_alignParentTop="true"
-            android:layout_toStartOf="@+id/tunnel_switch"
             android:ellipsize="end"
             android:maxLines="1"
             android:text="@{key}" />
@@ -52,5 +51,5 @@
             android:layout_alignParentEnd="true"
             app:checked="@{item.state == State.UP}"
             app:onBeforeCheckedChanged="@{fragment::setTunnelState}" />
-    </RelativeLayout>
+    </com.wireguard.android.widget.MultiselectableRelativeLayout>
 </layout>

app/src/main/res/values-ldrtl/fab.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <integer name="label_position">1</integer>
+</resources>

app/src/main/res/values-night/colors.xml

@@ -1,10 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <!-- TODO(msf): remove these 4 hard-coded colors and replace with theme colors -->
-    <color name="list_item_activated">#64cfd8dc</color>
-    <color name="list_item_ripple">#a0808e95</color>
+    <!-- TODO(msf): remove these 2 hard-coded colors and replace with theme colors -->
     <color name="fab_label_text_color">#000000</color>
     <color name="fab_label_background_color">#bbbbbb</color>
 
-    <color name="accent">#BBDEFB</color>
+    <color name="accent">#5e97f6</color>
 </resources>

app/src/main/res/values/attrs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <declare-styleable name="Multiselected">
+        <attr name="state_multiselected" format="boolean"/>
+    </declare-styleable>
+</resources>

app/src/main/res/values/colors.xml

@@ -1,8 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <!-- TODO(msf): remove these 4 hard-coded colors and replace with theme colors -->
-    <color name="list_item_activated">#cfd8dc</color> <!-- Blue Grey 200 -->
-    <color name="list_item_ripple">#808e95</color> <!-- Blue Grey 200 dark -->
+    <!-- TODO(msf): remove these 2 hard-coded colors and replace with theme colors -->
     <color name="fab_label_text_color">#ffffff</color>
     <color name="fab_label_background_color">#444444</color>
 

app/src/main/res/values/dimens.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <dimen name="fab_margin">16dp</dimen>
+</resources>

app/src/main/res/values/fab.xml

@@ -27,4 +27,5 @@
             <enum name="right" value="3"/>
         </attr>
     </declare-styleable>
+    <integer name="label_position">0</integer>
 </resources>

app/src/main/res/values/strings.xml

@@ -30,6 +30,8 @@
     <string name="create_activity_title">Create WireGuard Tunnel</string>
     <string name="create_empty">Create from scratch</string>
     <string name="create_from_file">Create from file or archive</string>
+    <string name="create_from_qrcode">Create from QR code</string>
+    <string name="create_tunnel">Create Tunnel</string>
     <string name="dark_theme_title">Use dark theme</string>
     <string name="dark_theme_summary_on">Currently using dark night theme</string>
     <string name="dark_theme_summary_off">Currently using light day theme</string>
@@ -50,6 +52,7 @@
     <string name="hint_generated">(generated)</string>
     <string name="hint_optional">(optional)</string>
     <string name="hint_random">(random)</string>
+    <string name="import_from_qrcode">Import Tunnel from QR Code</string>
     <string name="import_error">Unable to import tunnel: %s</string>
     <string name="import_success">Imported “%s”</string>
     <string name="interface_title">Interface</string>
@@ -68,6 +71,7 @@
     <string name="private_key">Private key</string>
     <string name="public_key">Public key</string>
     <string name="public_key_description">Public key</string>
+    <string name="qrcode_hint">Tip: generate with `qrencode -t ansiutf8 &lt; tunnel.conf`.</string>
     <string name="restore_on_boot_summary">Bring up previously-enabled tunnels on boot</string>
     <string name="restore_on_boot_title">Restore on boot</string>
     <string name="save">Save</string>
@@ -89,8 +93,22 @@
     <string name="tools_installer_title">Install command line tools</string>
     <string name="tunnel_create_error">Unable to create tunnel: %s</string>
     <string name="tunnel_create_success">Successfully created tunnel “%s”</string>
+    <string name="tunnel_list_placeholder">Add a tunnel using the blue button</string>
+    <string name="tunnel_name">Tunnel Name</string>
     <string name="tunnel_rename_error">Unable to rename tunnel: %s</string>
     <string name="tunnel_rename_success">Successfully renamed tunnel to “%s”</string>
+    <string name="tunnel_error_invalid_name">Invalid name</string>
+    <string name="tunnel_error_already_exists">Tunnel %s already exists</string>
+    <string name="tunnel_error_empty_inetaddress">Empty address</string>
+    <string name="tunnel_error_empty_interface_address">Address is empty</string>
+    <string name="tunnel_error_interface_parse_failed">Unable to parse line: “%s”</string>
+    <string name="tunnel_error_forbidden_endpoint_chars">Forbidden characters in endpoint</string>
+    <string name="tunnel_error_empty_peer_public_key">Peer public key may not be empty</string>
+    <string name="tunnel_error_invalid_config_line">Invalid configuration line: %s</string>
+    <string name="tunnel_error_no_config_information">Could not find any config information</string>
+    <string name="key_length_base64_exception_message">WireGuard base64 keys must be 44 characters encoding 32 bytes</string>
+    <string name="key_length_exception_message">WireGuard keys must be 32 bytes</string>
+    <string name="key_length_hex_exception_message">WireGuard hex keys must be 64 characters encoding 32 bytes</string>
     <string name="version_title">WireGuard for Android v%s"</string>
     <string name="version_summary">%s backend v%s</string>
     <string name="version_summary_checking">Checking %s backend version</string>

app/tools/CMakeLists.txt

@@ -8,12 +8,12 @@ set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_LIBRARY_OUTPUT_DIRECTORY}")
 # Work around https://github.com/android-ndk/ndk/issues/602
 set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fuse-ld=gold")
 
-add_executable(libwg-quick.so wireguard/src/tools/wg-quick/android.c)
-target_compile_options(libwg-quick.so PUBLIC -O3 -std=gnu11 -Wall -pedantic -Wno-missing-field-initializers)
+add_executable(libwg-quick.so wireguard/src/tools/wg-quick/android.c ndk-compat/compat.c)
+target_compile_options(libwg-quick.so PUBLIC -O3 -std=gnu11 -Wall -pedantic -Wno-missing-field-initializers -include ${CMAKE_CURRENT_SOURCE_DIR}/ndk-compat/compat.h -DWG_PACKAGE_NAME=\"${ANDROID_PACKAGE_NAME}\")
 
-file(GLOB WG_SOURCES wireguard/src/tools/*.c libmnl/src/*.c)
+file(GLOB WG_SOURCES wireguard/src/tools/*.c libmnl/src/*.c ndk-compat/compat.c)
 add_executable(libwg.so ${WG_SOURCES})
-target_compile_options(libwg.so PUBLIC -idirafter "${CMAKE_CURRENT_SOURCE_DIR}/libmnl/include/" -I "${CMAKE_CURRENT_SOURCE_DIR}/wireguard/src/tools/" -O3 -std=gnu11 -D_GNU_SOURCE -DHAVE_VISIBILITY_HIDDEN -DRUNSTATEDIR=\"\\\"/data/data/com.wireguard.android/cache\\\"\" -Wno-pointer-arith -Wno-unused-parameter)
+target_compile_options(libwg.so PUBLIC -idirafter "${CMAKE_CURRENT_SOURCE_DIR}/libmnl/include/" -I "${CMAKE_CURRENT_SOURCE_DIR}/wireguard/src/tools/" -O3 -std=gnu11 -D_GNU_SOURCE -include ${CMAKE_CURRENT_SOURCE_DIR}/ndk-compat/compat.h -DHAVE_VISIBILITY_HIDDEN -DRUNSTATEDIR=\"/data/data/${ANDROID_PACKAGE_NAME}/cache\" -Wno-pointer-arith -Wno-unused-parameter)
 
 add_custom_target(libwg-go.so WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/libwg-go" COMMENT "Building wireguard-go" VERBATIM COMMAND make
     ANDROID_ARCH_NAME=${ANDROID_ARCH_NAME}
@@ -21,6 +21,7 @@ add_custom_target(libwg-go.so WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/lib
     ANDROID_TOOLCHAIN_ROOT=${ANDROID_TOOLCHAIN_ROOT}
     ANDROID_LLVM_TRIPLE=${ANDROID_LLVM_TRIPLE}
     ANDROID_SYSROOT=${ANDROID_SYSROOT}
+    ANDROID_PACKAGE_NAME=${ANDROID_PACKAGE_NAME}
     CFLAGS=${CMAKE_C_FLAGS}\ -Wno-unused-command-line-argument
     LDFLAGS=${CMAKE_SHARED_LINKER_FLAGS}\ -fuse-ld=gold
     DESTDIR=${CMAKE_LIBRARY_OUTPUT_DIRECTORY}

app/tools/libwg-go/Makefile

@@ -23,7 +23,7 @@ default: $(DESTDIR)/libwg-go.so
 
 GOBUILDARCH := $(NDK_GO_ARCH_MAP_$(shell uname -m))
 GOBUILDOS := $(shell uname -s | tr '[:upper:]' '[:lower:]')
-GOBUILDVERSION := 1.10.2
+GOBUILDVERSION := 1.11
 GOBUILDTARBALL := https://dl.google.com/go/go$(GOBUILDVERSION).$(GOBUILDOS)-$(GOBUILDARCH).tar.gz
 GOBUILDVERSION_NEEDED := go version go$(GOBUILDVERSION) $(GOBUILDOS)/$(GOBUILDARCH)
 
@@ -54,5 +54,5 @@ $(DESTDIR)/libwg-go.so: $(FILES) src/git.zx2c4.com/wireguard-go/api-android.go s
 	mkdir -p $(subst ../wireguard-go/,./src/git.zx2c4.com/wireguard-go/,$(dir $(FILES)))
 	$(foreach FILE,$(FILES),ln -sfrt $(subst ../wireguard-go/,./src/git.zx2c4.com/wireguard-go/,$(dir $(FILE))) $(FILE);)
 	GOPATH=$(PWD) go get -v -d git.zx2c4.com/wireguard-go
-	GOPATH=$(PWD) go build -v -o $(DESTDIR)/libwg-go.so -buildmode c-shared git.zx2c4.com/wireguard-go
+	GOPATH=$(PWD) go build -ldflags="-X main.socketDirectory=/data/data/$(ANDROID_PACKAGE_NAME)/cache/wireguard" -v -o $(DESTDIR)/libwg-go.so -buildmode c-shared git.zx2c4.com/wireguard-go
 	go version > .gobuildversion

app/tools/libwg-go/goruntime-boottime-over-monotonic.diff

@@ -1,7 +1,28 @@
-diff -ru b/src/runtime/sys_linux_386.s a/src/runtime/sys_linux_386.s
---- b/src/runtime/sys_linux_386.s	2018-04-30 22:26:39.000000000 +0200
-+++ a/src/runtime/sys_linux_386.s	2018-05-09 17:09:42.319531743 +0200
-@@ -287,13 +287,13 @@
+From 6f345a38d9533db388009d91d29981673dcf95b4 Mon Sep 17 00:00:00 2001
+From: Jason A. Donenfeld <Jason@zx2c4.com>
+Date: Fri, 04 May 2018 03:48:23 +0200
+Subject: [PATCH] runtime: use CLOCK_BOOTTIME in nanotime on Linux
+
+This makes timers account for having expired while a computer was
+asleep, which is quite common on mobile devices. Note that BOOTTIME is
+identical to MONOTONIC, except that it takes into account time spent
+in suspend. In Linux 4.17, the kernel will actually make MONOTONIC act
+like BOOTTIME anyway, so this switch will additionally unify the
+timer behavior across kernels.
+
+BOOTTIME was introduced into Linux 2.6.39-rc1 with 70a08cca1227d in
+2011.
+
+Fixes #24595
+
+Change-Id: I7b2a6ca0c5bc5fce57ec0eeafe7b68270b429321
+---
+
+diff --git a/src/runtime/sys_linux_386.s b/src/runtime/sys_linux_386.s
+index 8d5a4ff..bfad064 100644
+--- a/src/runtime/sys_linux_386.s
++++ b/src/runtime/sys_linux_386.s
+@@ -285,13 +285,13 @@
  
  	LEAL	8(SP), BX	// &ts (struct timespec)
  	MOVL	BX, 4(SP)
@@ -17,11 +38,12 @@ diff -ru b/src/runtime/sys_linux_386.s a/src/runtime/sys_linux_386.s
  	LEAL	8(SP), CX
  	INVOKE_SYSCALL
  
-diff -ru b/src/runtime/sys_linux_amd64.s a/src/runtime/sys_linux_amd64.s
---- b/src/runtime/sys_linux_amd64.s	2018-04-30 22:26:39.000000000 +0200
-+++ a/src/runtime/sys_linux_amd64.s	2018-05-09 17:09:42.319531743 +0200
-@@ -258,7 +258,7 @@
- 	MOVQ	runtime·__vdso_clock_gettime_sym(SB), AX
+diff --git a/src/runtime/sys_linux_amd64.s b/src/runtime/sys_linux_amd64.s
+index 62d8024..8510be4 100644
+--- a/src/runtime/sys_linux_amd64.s
++++ b/src/runtime/sys_linux_amd64.s
+@@ -257,7 +257,7 @@
+ 	MOVQ	runtime·vdsoClockgettimeSym(SB), AX
  	CMPQ	AX, $0
  	JEQ	fallback
 -	MOVL	$1, DI // CLOCK_MONOTONIC
@@ -29,34 +51,55 @@ diff -ru b/src/runtime/sys_linux_amd64.s a/src/runtime/sys_linux_amd64.s
  	LEAQ	0(SP), SI
  	CALL	AX
  	MOVQ	0(SP), AX	// sec
-diff -ru b/src/runtime/sys_linux_arm64.s a/src/runtime/sys_linux_arm64.s
---- b/src/runtime/sys_linux_arm64.s	2018-04-30 22:26:39.000000000 +0200
-+++ a/src/runtime/sys_linux_arm64.s	2018-05-09 17:12:47.844591628 +0200
-@@ -201,7 +201,7 @@
- 	RET
+diff --git a/src/runtime/sys_linux_arm.s b/src/runtime/sys_linux_arm.s
+index aa39732..d29cb88 100644
+--- a/src/runtime/sys_linux_arm.s
++++ b/src/runtime/sys_linux_arm.s
+@@ -11,7 +11,7 @@
+ #include "textflag.h"
  
- TEXT runtime·nanotime(SB),NOSPLIT,$24-8
--	MOVW	$1, R0 // CLOCK_MONOTONIC
-+	MOVW	$7, R0 // CLOCK_BOOTTIME
- 	MOVD	RSP, R1
- 	MOVD	$SYS_clock_gettime, R8
- 	SVC
-diff -ru b/src/runtime/sys_linux_arm.s a/src/runtime/sys_linux_arm.s
---- b/src/runtime/sys_linux_arm.s	2018-04-30 22:26:39.000000000 +0200
-+++ a/src/runtime/sys_linux_arm.s	2018-05-09 17:13:18.983281049 +0200
-@@ -235,7 +235,7 @@
+ #define CLOCK_REALTIME	0
+-#define CLOCK_MONOTONIC	1
++#define CLOCK_BOOTTIME	7
  
- // int64 nanotime(void)
- TEXT runtime·nanotime(SB),NOSPLIT,$32
--	MOVW	$1, R0  // CLOCK_MONOTONIC
-+	MOVW	$7, R0  // CLOCK_BOOTTIME
- 	MOVW	$8(R13), R1  // timespec
- 	MOVW	$SYS_clock_gettime, R7
- 	SWI	$0
-diff -ru b/src/runtime/sys_linux_mips64x.s a/src/runtime/sys_linux_mips64x.s
---- b/src/runtime/sys_linux_mips64x.s	2018-04-30 22:26:39.000000000 +0200
-+++ a/src/runtime/sys_linux_mips64x.s	2018-05-09 17:09:42.321531721 +0200
-@@ -197,7 +197,7 @@
+ // for EABI, as we don't support OABI
+ #define SYS_BASE 0x0
+@@ -287,7 +287,7 @@
+ 	SUB	$24, R13	// Space for results
+ 	BIC	$0x7, R13	// Align for C code
+ 
+-	MOVW	$CLOCK_MONOTONIC, R0
++	MOVW	$CLOCK_BOOTTIME, R0
+ 	MOVW	$8(R13), R1	// timespec
+ 	MOVW	runtime·vdsoClockgettimeSym(SB), R11
+ 	CMP	$0, R11
+diff --git a/src/runtime/sys_linux_arm64.s b/src/runtime/sys_linux_arm64.s
+index c6afd76..24294e8 100644
+--- a/src/runtime/sys_linux_arm64.s
++++ b/src/runtime/sys_linux_arm64.s
+@@ -13,7 +13,7 @@
+ #define AT_FDCWD -100
+ 
+ #define CLOCK_REALTIME 0
+-#define CLOCK_MONOTONIC 1
++#define CLOCK_BOOTTIME 7
+ 
+ #define SYS_exit		93
+ #define SYS_read		63
+@@ -243,7 +243,7 @@
+ 	BIC	$15, R1
+ 	MOVD	R1, RSP
+ 
+-	MOVW	$CLOCK_MONOTONIC, R0
++	MOVW	$CLOCK_BOOTTIME, R0
+ 	MOVD	runtime·vdsoClockgettimeSym(SB), R2
+ 	CBZ	R2, fallback
+ 	BL	(R2)
+diff --git a/src/runtime/sys_linux_mips64x.s b/src/runtime/sys_linux_mips64x.s
+index 8e64f1c..521062f 100644
+--- a/src/runtime/sys_linux_mips64x.s
++++ b/src/runtime/sys_linux_mips64x.s
+@@ -185,7 +185,7 @@
  	RET
  
  TEXT runtime·nanotime(SB),NOSPLIT,$16
@@ -65,10 +108,11 @@ diff -ru b/src/runtime/sys_linux_mips64x.s a/src/runtime/sys_linux_mips64x.s
  	MOVV	$0(R29), R5
  	MOVV	$SYS_clock_gettime, R2
  	SYSCALL
-diff -ru b/src/runtime/sys_linux_mipsx.s a/src/runtime/sys_linux_mipsx.s
---- b/src/runtime/sys_linux_mipsx.s	2018-04-30 22:26:39.000000000 +0200
-+++ a/src/runtime/sys_linux_mipsx.s	2018-05-09 17:09:42.321531721 +0200
-@@ -202,7 +202,7 @@
+diff --git a/src/runtime/sys_linux_mipsx.s b/src/runtime/sys_linux_mipsx.s
+index a6bca3b..920ed9a 100644
+--- a/src/runtime/sys_linux_mipsx.s
++++ b/src/runtime/sys_linux_mipsx.s
+@@ -189,7 +189,7 @@
  	RET
  
  TEXT runtime·nanotime(SB),NOSPLIT,$8-8
@@ -77,10 +121,11 @@ diff -ru b/src/runtime/sys_linux_mipsx.s a/src/runtime/sys_linux_mipsx.s
  	MOVW	$4(R29), R5
  	MOVW	$SYS_clock_gettime, R2
  	SYSCALL
-diff -ru b/src/runtime/sys_linux_ppc64x.s a/src/runtime/sys_linux_ppc64x.s
---- b/src/runtime/sys_linux_ppc64x.s	2018-04-30 22:26:39.000000000 +0200
-+++ a/src/runtime/sys_linux_ppc64x.s	2018-05-09 17:09:42.322531710 +0200
-@@ -176,7 +176,7 @@
+diff --git a/src/runtime/sys_linux_ppc64x.s b/src/runtime/sys_linux_ppc64x.s
+index 483cb8e..11f3c49 100644
+--- a/src/runtime/sys_linux_ppc64x.s
++++ b/src/runtime/sys_linux_ppc64x.s
+@@ -164,7 +164,7 @@
  	RET
  
  TEXT runtime·nanotime(SB),NOSPLIT,$16
@@ -89,10 +134,11 @@ diff -ru b/src/runtime/sys_linux_ppc64x.s a/src/runtime/sys_linux_ppc64x.s
  	MOVD	$0(R1), R4
  	SYSCALL	$SYS_clock_gettime
  	MOVD	0(R1), R3	// sec
-diff -ru b/src/runtime/sys_linux_s390x.s a/src/runtime/sys_linux_s390x.s
---- b/src/runtime/sys_linux_s390x.s	2018-04-30 22:26:39.000000000 +0200
-+++ a/src/runtime/sys_linux_s390x.s	2018-05-09 17:09:42.322531710 +0200
-@@ -188,7 +188,7 @@
+diff --git a/src/runtime/sys_linux_s390x.s b/src/runtime/sys_linux_s390x.s
+index 1ff110c..e9049e0 100644
+--- a/src/runtime/sys_linux_s390x.s
++++ b/src/runtime/sys_linux_s390x.s
+@@ -176,7 +176,7 @@
  	RET
  
  TEXT runtime·nanotime(SB),NOSPLIT,$16

app/tools/libwg-go/src/git.zx2c4.com/wireguard-go/api-android.go

@@ -16,6 +16,7 @@ import (
 	"io/ioutil"
 	"log"
 	"math"
+	"net"
 	"os"
 	"os/signal"
 	"runtime"
@@ -33,11 +34,16 @@ func (l AndroidLogger) Write(p []byte) (int, error) {
 	return len(p), nil
 }
 
-var tunnelHandles map[int32]*Device
+type TunnelHandle struct {
+	device *Device
+	uapi   net.Listener
+}
+
+var tunnelHandles map[int32]TunnelHandle
 
 func init() {
 	roamingDisabled = true
-	tunnelHandles = make(map[int32]*Device)
+	tunnelHandles = make(map[int32]TunnelHandle)
 	signals := make(chan os.Signal)
 	signal.Notify(signals, unix.SIGUSR2)
 	go func() {
@@ -85,6 +91,29 @@ func wgTurnOn(ifnameRef string, tun_fd int32, settings string) int32 {
 		return -1
 	}
 
+	var uapi net.Listener;
+
+	uapiFile, err := UAPIOpen(name)
+	if err != nil {
+		logger.Error.Println(err)
+	} else {
+		uapi, err = UAPIListen(name, uapiFile)
+		if err != nil {
+			uapiFile.Close()
+			logger.Error.Println(err)
+		} else {
+			go func() {
+				for {
+					conn, err := uapi.Accept()
+					if err != nil {
+						return
+					}
+					go ipcHandle(device, conn)
+				}
+			}()
+		}
+	}
+
 	device.Up()
 	logger.Info.Println("Device started")
 
@@ -98,27 +127,30 @@ func wgTurnOn(ifnameRef string, tun_fd int32, settings string) int32 {
 		unix.Close(int(tun_fd))
 		return -1
 	}
-	tunnelHandles[i] = device
+	tunnelHandles[i] = TunnelHandle{device: device, uapi: uapi}
 	return i
 }
 
 //export wgTurnOff
 func wgTurnOff(tunnelHandle int32) {
-	device, ok := tunnelHandles[tunnelHandle]
+	handle, ok := tunnelHandles[tunnelHandle]
 	if !ok {
 		return
 	}
 	delete(tunnelHandles, tunnelHandle)
-	device.Close()
+	if handle.uapi != nil {
+		handle.uapi.Close()
+	}
+	handle.device.Close()
 }
 
 //export wgGetSocketV4
 func wgGetSocketV4(tunnelHandle int32) int32 {
-	device, ok := tunnelHandles[tunnelHandle]
+	handle, ok := tunnelHandles[tunnelHandle]
 	if !ok {
 		return -1
 	}
-	native, ok := device.net.bind.(*NativeBind)
+	native, ok := handle.device.net.bind.(*NativeBind)
 	if !ok {
 		return -1
 	}
@@ -138,11 +170,11 @@ func wgGetSocketV4(tunnelHandle int32) int32 {
 
 //export wgGetSocketV6
 func wgGetSocketV6(tunnelHandle int32) int32 {
-	device, ok := tunnelHandles[tunnelHandle]
+	handle, ok := tunnelHandles[tunnelHandle]
 	if !ok {
 		return -1
 	}
-	native, ok := device.net.bind.(*NativeBind)
+	native, ok := handle.device.net.bind.(*NativeBind)
 	if !ok {
 		return -1
 	}

app/tools/ndk-compat/compat.c

@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: BSD
+ *
+ * Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ */
+
+#define FILE_IS_EMPTY
+
+#if defined(__ANDROID_API__) && __ANDROID_API__ < 18
+#undef FILE_IS_EMPTY
+#include <stdio.h>
+#include <stdlib.h>
+
+ssize_t getdelim(char **buf, size_t *bufsiz, int delimiter, FILE *fp)
+{
+	char *ptr, *eptr;
+
+	if (*buf == NULL || *bufsiz == 0) {
+		*bufsiz = BUFSIZ;
+		if ((*buf = malloc(*bufsiz)) == NULL)
+			return -1;
+	}
+
+	for (ptr = *buf, eptr = *buf + *bufsiz;;) {
+		int c = fgetc(fp);
+		if (c == -1) {
+			if (feof(fp)) {
+				ssize_t diff = (ssize_t)(ptr - *buf);
+				if (diff != 0) {
+					*ptr = '\0';
+					return diff;
+				}
+			}
+			return -1;
+		}
+		*ptr++ = c;
+		if (c == delimiter) {
+			*ptr = '\0';
+			return ptr - *buf;
+		}
+		if (ptr + 2 >= eptr) {
+			char *nbuf;
+			size_t nbufsiz = *bufsiz * 2;
+			ssize_t d = ptr - *buf;
+			if ((nbuf = realloc(*buf, nbufsiz)) == NULL)
+				return -1;
+			*buf = nbuf;
+			*bufsiz = nbufsiz;
+			eptr = nbuf + nbufsiz;
+			ptr = nbuf + d;
+		}
+	}
+}
+
+ssize_t getline(char **buf, size_t *bufsiz, FILE *fp)
+{
+	return getdelim(buf, bufsiz, '\n', fp);
+}
+#endif
+
+#if defined(__ANDROID_API__) && __ANDROID_API__ < 24
+#undef FILE_IS_EMPTY
+#include <string.h>
+
+char *strchrnul(const char *s, int c)
+{
+        char *x = strchr(s, c);
+        if (!x)
+                return (char *)s + strlen(s);
+        return x;
+}
+#endif
+
+#ifdef FILE_IS_EMPTY
+#undef FILE_IS_EMPTY
+static char ____x __attribute__((unused));
+#endif

app/tools/ndk-compat/compat.h

@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: BSD
+ *
+ * Copyright (C) 2015-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ */
+
+#if defined(__ANDROID_API__) && __ANDROID_API__ < 18
+#include <stdio.h>
+ssize_t getdelim(char **buf, size_t *bufsiz, int delimiter, FILE *fp);
+ssize_t getline(char **buf, size_t *bufsiz, FILE *fp);
+#endif
+
+#if defined(__ANDROID_API__) && __ANDROID_API__ < 24
+char *strchrnul(const char *s, int c);
+#endif
+

build.gradle

@@ -7,7 +7,7 @@ allprojects {
 
 buildscript {
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.1.3'
+        classpath 'com.android.tools.build:gradle:3.1.4'
     }
     repositories {
         google()