ViewUtils.java

public class ViewUtils
{
    /**
     * Starts animations inside a LayerDrawable
     *
     * @param drawable
     */
    public static void startLayerAnimation(LayerDrawable drawable)
    {
        for (int i = 0; i < drawable.getNumberOfLayers(); ++i)
        {
            Drawable dr = drawable.getDrawable(i);
            if (dr instanceof Animatable)
            {
                ((Animatable) dr).start();
            }
            if (dr instanceof LayerDrawable)
            {
                startLayerAnimation((LayerDrawable) dr);
            }
        }
    }
}