Мне нужно было знать, когда завершается мой одноразовый AnimationDrawable, без необходимости создавать подкласс AnimationDrawable, поскольку я должен установить список анимации в XML. Я написал этот класс и проверил его на Gingerbread и ICS. Его можно легко расширить, чтобы сделать обратный вызов для каждого кадра.
/**
* Provides a callback when a non-looping {@link AnimationDrawable} completes its animation sequence. More precisely,
* {@link #onAnimationComplete()} is triggered when {@link View#invalidateDrawable(Drawable)} has been called on the
* last frame.
*
* @author Benedict Lau
*/
public abstract class AnimationDrawableCallback implements Callback {
/**
* The last frame of {@link Drawable} in the {@link AnimationDrawable}.
*/
private Drawable mLastFrame;
/**
* The client's {@link Callback} implementation. All calls are proxied to this wrapped {@link Callback}
* implementation after intercepting the events we need.
*/
private Callback mWrappedCallback;
/**
* Flag to ensure that {@link #onAnimationComplete()} is called only once, since
* {@link #invalidateDrawable(Drawable)} may be called multiple times.
*/
private boolean mIsCallbackTriggered = false;
/**
*
* @param animationDrawable
* the {@link AnimationDrawable}.
* @param callback
* the client's {@link Callback} implementation. This is usually the {@link View} the has the
* {@link AnimationDrawable} as background.
*/
public AnimationDrawableCallback(AnimationDrawable animationDrawable, Callback callback) {
mLastFrame = animationDrawable.getFrame(animationDrawable.getNumberOfFrames() - 1);
mWrappedCallback = callback;
}
@Override
public void invalidateDrawable(Drawable who) {
if (mWrappedCallback != null) {
mWrappedCallback.invalidateDrawable(who);
}
if (!mIsCallbackTriggered && mLastFrame != null && mLastFrame.equals(who.getCurrent())) {
mIsCallbackTriggered = true;
onAnimationComplete();
}
}
@Override
public void scheduleDrawable(Drawable who, Runnable what, long when) {
if (mWrappedCallback != null) {
mWrappedCallback.scheduleDrawable(who, what, when);
}
}
@Override
public void unscheduleDrawable(Drawable who, Runnable what) {
if (mWrappedCallback != null) {
mWrappedCallback.unscheduleDrawable(who, what);
}
}
//
// Public methods.
//
/**
* Callback triggered when {@link View#invalidateDrawable(Drawable)} has been called on the last frame, which marks
* the end of a non-looping animation sequence.
*/
public abstract void onAnimationComplete();
}
Вот как это использовать.
AnimationDrawable countdownAnimation = (AnimationDrawable) mStartButton.getBackground();
countdownAnimation.setCallback(new AnimationDrawableCallback(countdownAnimation, mStartButton) {
@Override
public void onAnimationComplete() {
// TODO Do something.
}
});
countdownAnimation.start();