tests/java_api/HealingBrush/res/layout/activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/button"    >
    <ImageView
        android:id="@+id/imageview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#333"
        android:scaleType="matrix" />

    <rs.example.android.com.healingbrush.DrawView
        android:id="@+id/overlay"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
     </FrameLayout>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Heal"
        android:onClick="heal"
        android:id="@+id/button"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Undo"
        android:onClick="undo"
        android:id="@+id/button2"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Save"
        android:onClick="save"
        android:id="@+id/button3"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true" />

</RelativeLayout>