6.6 Android Framework - TransitionDrawable

<?xml version="1.0" encoding="utf-8"?>
<transition xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:drawable="@drawable/@[package:]drawable/drawable_res"
android:id="@[+][package:]id/id"
android:top="dimension"
android:left="dimension"
android:right="dimension"
android:bottom="dimension" />
</transition>

TransitonDrawable#startTransition

TransitonDrawable#reverseTransition