AnimatedImageView.java 文件源码

private void reverse() {
    Drawable current = getDrawable();
    if (current instanceof Animatable2) {
        ((Animatable2) current).unregisterAnimationCallback(callback);
    }
    if (otherDrawable instanceof Animatable2) {
        ((Animatable2) otherDrawable).registerAnimationCallback(callback);
        ((Animatable2) otherDrawable).start();
    }
    setImageDrawable(otherDrawable);
    otherDrawable = current;
}