arcanechat-android/res/layout/welcome_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    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"
    tools:context=".WelcomeActivity">

    <android.support.v4.view.ViewPager
        android:id="@+id/welcome_viewpager"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toTopOf="@id/welcome_page_tab_layout"/>

    <android.support.design.widget.TabLayout
        android:id="@+id/welcome_page_tab_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toTopOf="@id/skip_button_top_spacer"
        app:tabBackground="@drawable/paging_indicator"
        app:tabGravity="center"
        app:tabIndicatorHeight="0dp"/>

    <android.support.v4.widget.Space
        android:id="@+id/skip_button_top_spacer"
        android:layout_width="match_parent"
        android:layout_height="32dp"
        app:layout_constraintBottom_toTopOf="@id/skip_button"/>

    <com.dd.CircularProgressButton
        android:id="@+id/skip_button"
        android:layout_width="wrap_content"
        android:layout_height="40dp"
        android:background="@color/signal_primary"
        android:paddingEnd="8dp"
        android:paddingStart="8dp"
        android:textColor="@color/white"
        app:cpb_colorIndicator="@color/white"
        app:cpb_colorProgress="@color/textsecure_primary"
        app:cpb_cornerRadius="20dp"
        app:cpb_selectorIdle="@drawable/progress_button_state"
        app:cpb_textIdle="@string/welcome_start_messaging"
        app:layout_constraintBottom_toTopOf="@id/skip_button_bottom_spacer"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"/>

    <android.support.v4.widget.Space
        android:id="@+id/skip_button_bottom_spacer"
        android:layout_width="match_parent"
        android:layout_height="32dp"
        app:layout_constraintBottom_toTopOf="@id/backup_text"/>

    <TextView
        android:id="@+id/backup_text"
        android:layout_width="wrap_content"
        android:layout_height="48dp"
        android:gravity="center"
        android:text="Import backup"
        android:textColor="@color/blue_400"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/backup_icon"
        app:layout_constraintHorizontal_chainStyle="packed"
        app:layout_constraintStart_toStartOf="parent"/>

    <ImageView
        android:id="@+id/backup_icon"
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:padding="8dp"
        android:src="@drawable/ic_folder_white_48dp"
        android:tint="@color/blue_400"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_chainStyle="packed"
        app:layout_constraintStart_toEndOf="@id/backup_text"
        app:layout_constraintTop_toBottomOf="@id/skip_button_bottom_spacer"/>

</android.support.constraint.ConstraintLayout>