arcanechat-android/res/layout/registration_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fillViewport="true"
    tools:context=".RegistrationActivity">

    <android.support.constraint.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:animateLayoutChanges="true">

        <android.support.constraint.Guideline
            android:id="@+id/guideline_root_start_shifted"
            android:layout_width="wrap_content"
            android:layout_height="16dp"
            android:orientation="vertical"
            app:layout_constraintGuide_begin="14dp" />

        <android.support.constraint.Guideline
            android:id="@+id/guideline_root_start"
            android:layout_width="wrap_content"
            android:layout_height="16dp"
            android:orientation="vertical"
            app:layout_constraintGuide_begin="16dp" />

        <android.support.constraint.Guideline
            android:id="@+id/guideline_root_end"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            app:layout_constraintGuide_end="16dp" />

        <android.support.v4.widget.Space
            android:id="@+id/fab_spacer"
            android:layout_width="wrap_content"
            android:layout_height="28dp" />

        <android.support.design.widget.TextInputLayout
            android:id="@+id/email"
            android:layout_width="0dp"
            android:layout_height="58dp"
            app:errorEnabled="true"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/fab_spacer">

            <android.support.design.widget.TextInputEditText
                android:id="@+id/email_text"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/email_address"
                android:inputType="textEmailAddress" />

        </android.support.design.widget.TextInputLayout>

        <android.support.design.widget.TextInputLayout
            android:id="@+id/password"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/email"
            app:passwordToggleEnabled="true">

            <android.support.design.widget.TextInputEditText
                android:id="@+id/password_text"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/password"
                android:inputType="textPassword" />

        </android.support.design.widget.TextInputLayout>

        <TextView
            android:id="@+id/no_servers_hint"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:gravity="left"
            android:padding="16dp"
            android:text="@string/login_no_servers_hint"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@id/password" />

        <android.support.constraint.Group
            android:id="@+id/advanced_group"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:visibility="gone"
            app:constraint_referenced_ids="inbox, imap_login, imap_server, imap_port, imap_security_label, imap_security, outbox_view_spacer_top,
            outbox, smtp_login, smtp_password, smtp_server, smtp_port, smtp_security_label, smtp_security, auth_method_label, auth_method, view_log_button" />

        <ImageView
            android:id="@+id/advanced_icon"
            android:layout_width="wrap_content"
            android:layout_height="40dp"
            android:contentDescription="@null"
            android:paddingTop="8dp"
            android:paddingBottom="8dp"
            android:src="@drawable/ic_close_white_24dp"
            android:tint="@color/blue_600"
            app:layout_constraintHorizontal_chainStyle="packed"
            app:layout_constraintStart_toStartOf="@+id/guideline_root_start_shifted"
            app:layout_constraintTop_toBottomOf="@id/no_servers_hint" />

        <TextView
            android:id="@+id/advanced_text"
            android:layout_width="wrap_content"
            android:layout_height="40dp"
            android:padding="8dp"
            android:gravity="start|center_vertical"
            android:text="@string/menu_advanced"
            android:textColor="@color/blue_400"
            android:textSize="16sp"
            app:layout_constraintHorizontal_chainStyle="packed"
            app:layout_constraintStart_toEndOf="@id/advanced_icon"
            app:layout_constraintTop_toBottomOf="@id/no_servers_hint" />

        <TextView
            android:id="@+id/inbox"
            android:layout_width="wrap_content"
            android:layout_height="24dp"
            android:gravity="center"
            android:paddingTop="8dp"
            android:text="@string/login_inbox"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/advanced_text" />

        <android.support.design.widget.TextInputLayout
            android:id="@+id/imap_login"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/inbox">

            <android.support.design.widget.TextInputEditText
                android:id="@+id/imap_login_text"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/login_imap_login" />

        </android.support.design.widget.TextInputLayout>

        <android.support.design.widget.TextInputLayout
            android:id="@+id/imap_server"
            android:layout_width="0dp"
            android:layout_height="58dp"
            app:errorEnabled="true"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/imap_login">

            <android.support.design.widget.TextInputEditText
                android:id="@+id/imap_server_text"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/login_imap_server"
                android:inputType="text|textNoSuggestions" />

        </android.support.design.widget.TextInputLayout>

        <android.support.design.widget.TextInputLayout
            android:id="@+id/imap_port"
            android:layout_width="0dp"
            android:layout_height="58dp"
            app:errorEnabled="true"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/imap_server">

            <android.support.design.widget.TextInputEditText
                android:id="@+id/imap_port_text"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/login_imap_port"
                android:inputType="number" />

        </android.support.design.widget.TextInputLayout>

        <TextView
            android:id="@+id/imap_security_label"
            style="@style/TextAppearance.AppCompat.Caption"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="@string/login_imap_security"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/imap_port" />

        <Spinner
            android:id="@+id/imap_security"
            android:layout_width="0dp"
            android:layout_height="48dp"
            android:entries="@array/server_security"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/imap_security_label" />

        <android.support.v4.widget.Space
            android:id="@+id/outbox_view_spacer_top"
            android:layout_width="wrap_content"
            android:layout_height="16dp"
            app:layout_constraintTop_toBottomOf="@id/imap_security" />

        <TextView
            android:id="@+id/outbox"
            android:layout_width="wrap_content"
            android:layout_height="24dp"
            android:gravity="center"
            android:text="@string/login_outbox"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/outbox_view_spacer_top" />

        <android.support.design.widget.TextInputLayout
            android:id="@+id/smtp_login"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/outbox">

            <android.support.design.widget.TextInputEditText
                android:id="@+id/smtp_login_text"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/login_smtp_login" />

        </android.support.design.widget.TextInputLayout>

        <android.support.design.widget.TextInputLayout
            android:id="@+id/smtp_password"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/smtp_login"
            app:passwordToggleEnabled="true">

            <android.support.design.widget.TextInputEditText
                android:id="@+id/smtp_password_text"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/login_smtp_password"
                android:inputType="textPassword" />

        </android.support.design.widget.TextInputLayout>

        <android.support.design.widget.TextInputLayout
            android:id="@+id/smtp_server"
            android:layout_width="0dp"
            android:layout_height="58dp"
            app:errorEnabled="true"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/smtp_password">

            <android.support.design.widget.TextInputEditText
                android:id="@+id/smtp_server_text"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/login_smtp_server"
                android:inputType="text|textNoSuggestions" />

        </android.support.design.widget.TextInputLayout>

        <android.support.design.widget.TextInputLayout
            android:id="@+id/smtp_port"
            android:layout_width="0dp"
            android:layout_height="58dp"
            app:errorEnabled="true"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/smtp_server">

            <android.support.design.widget.TextInputEditText
                android:id="@+id/smtp_port_text"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/login_smtp_port"
                android:inputType="number" />

        </android.support.design.widget.TextInputLayout>

        <TextView
            android:id="@+id/smtp_security_label"
            style="@style/TextAppearance.AppCompat.Caption"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="@string/login_smtp_security"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/smtp_port" />

        <Spinner
            android:id="@+id/smtp_security"
            android:layout_width="0dp"
            android:layout_height="48dp"
            android:entries="@array/server_security"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/smtp_security_label" />

        <TextView
            android:id="@+id/auth_method_label"
            style="@style/TextAppearance.AppCompat.Caption"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:paddingTop="16dp"
            android:text="@string/login_auth_method"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/smtp_security" />

        <Spinner
            android:id="@+id/auth_method"
            android:layout_width="0dp"
            android:layout_height="48dp"
            android:entries="@array/auth_methods"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/auth_method_label" />

        <TextView
            android:id="@+id/view_log_button"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:text="@string/pref_view_log"
            android:textColor="@color/blue_400"
            android:textSize="16sp"
            android:textStyle="normal"
            android:typeface="sans"
            android:paddingBottom="32dp"
            app:layout_constraintEnd_toEndOf="@id/guideline_root_end"
            app:layout_constraintStart_toStartOf="@id/guideline_root_start"
            app:layout_constraintTop_toBottomOf="@id/auth_method" />

        <TextView
            android:id="@+id/sub_header"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:gravity="left"
            android:paddingLeft="16dp"
            android:paddingRight="16dp"
            android:paddingTop="1dp"
            android:paddingBottom="16dp"
            android:text="@string/login_subheader"
            android:textColor="@color/gray50"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@id/view_log_button" />

    </android.support.constraint.ConstraintLayout>

</ScrollView>