res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/gallery_root"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    <include layout="@layout/gl_root_group"/>
    <FrameLayout android:id="@+id/header"
            android:visibility="gone"
            android:layout_alignParentTop="true"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>
    <FrameLayout android:id="@+id/footer"
            android:visibility="gone"
            android:layout_alignParentBottom="true"
            android:layout_alignParentLeft="true"
            android:layout_alignParentRight="true"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>
</RelativeLayout>