tests/LockTaskTests/res/layout/activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/root_launch"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.google.android.example.locktasktests.MainActivity" >
    <Button
        android:id="@+id/button_default"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:onClick="onButtonPressed"
        android:text="@string/launch_default" />
    <Button
        android:id="@+id/button_never"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:onClick="onButtonPressed"
        android:text="@string/launch_never" />
    <Button
        android:id="@+id/button_whitelist"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:onClick="onButtonPressed"
        android:text="@string/launch_whitelist" />
    <Button
        android:id="@+id/button_always"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:onClick="onButtonPressed"
        android:text="@string/launch_always" />
    <Button
        android:id="@+id/toast_pinned"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:onClick="onToast"
        android:text="@string/toast_pinned" />
</LinearLayout>