android开发：创建动态drawable

<?xml version="1.0" encoding="utf-8"?>
<animation-list
xmlns:android="http://schemas.android.com/apk/res/android"
android:oneshot="false">
<item android:drawable="@mipmap/audio_animation_list_left_1" android:duration="300"></item>
<item android:drawable="@mipmap/audio_animation_list_left_2" android:duration="300"></item>
<item android:drawable="@mipmap/audio_animation_list_left_3" android:duration="300"></item>
</animation-list>

private void play() {
if (animationView.getBackground() instanceof AnimationDrawable) {
AnimationDrawable animation = (AnimationDrawable) animationView.getBackground();
animation.start();
}
}

private void stop() {
if (animationView.getBackground() instanceof AnimationDrawable) {
AnimationDrawable animation = (AnimationDrawable) animationView.getBackground();
animation.stop();
animation.selectDrawable(2);
}
}