<!-- Animation frames are phase*.png files inside the
 res/drawable/ folder -->
<animation-list android:id="@+id/selected"
    android:oneshot="false"
    xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/example1" android:duration="400" />
    <item android:drawable="@drawable/example2" android:duration="400" />
    <item android:drawable="@drawable/example3" android:duration="400" />
</animation-list>