我想用幾個圖像文件制作一個動畫，為此，AnimationDrawable效果很好。但是，我需要知道動畫何時開始以及何時結束（即添加諸如Animation.AnimationListener之類的偵聽器）。搜索答案后，我很難過AnimationDrawable不支持偵聽器。有誰知道如何在Android上使用偵聽器創建逐幀圖像動畫？
3 回答
蠱毒傳說
TA貢獻1895條經驗 獲得超3個贊
我需要知道一次完成的AnimationDrawable何時完成，而不必將AnimationDrawable子類化，因為我必須以XML設置動畫列表。我寫了這個課，并在Gingerbread和ICS上進行了測試。它可以很容易地擴展以在每個幀上提供回調。
/**
* 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();
}
這是使用方法。
AnimationDrawable countdownAnimation = (AnimationDrawable) mStartButton.getBackground();
countdownAnimation.setCallback(new AnimationDrawableCallback(countdownAnimation, mStartButton) {
@Override
public void onAnimationComplete() {
// TODO Do something.
}
});
countdownAnimation.start();
當年話下
TA貢獻1890條經驗 獲得超9個贊
通過重寫AnimationDrawable類中的selectDrawable方法，可以輕松跟蹤動畫結束。完整的代碼如下：
public class AnimationDrawable2 extends AnimationDrawable
{
public interface IAnimationFinishListener
{
void onAnimationFinished();
}
private boolean finished = false;
private IAnimationFinishListener animationFinishListener;
public IAnimationFinishListener getAnimationFinishListener()
{
return animationFinishListener;
}
public void setAnimationFinishListener(IAnimationFinishListener animationFinishListener)
{
this.animationFinishListener = animationFinishListener;
}
@Override
public boolean selectDrawable(int idx)
{
boolean ret = super.selectDrawable(idx);
if ((idx != 0) && (idx == getNumberOfFrames() - 1))
{
if (!finished)
{
finished = true;
if (animationFinishListener != null) animationFinishListener.onAnimationFinished();
}
}
return ret;
}
}
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