Android ValueAnimator --内存泄漏

不是成功来得太慢，只是下的功夫还不够

最近在写一个关于贝塞尔曲线水波纹的小DEMO，发现关闭当前视图时报出内存泄漏的问题，检查下内存泄漏信息，经过排查发现是ValueAnimator的监听事件引起的，
先上解决方法：
在Activity/Fragment销毁时调用如下方法：

    public void release(){
        if (valueAnimator != null) {
            valueAnimator.cancel();
            valueAnimator.removeAllUpdateListeners();
        }
    }

找到问题就好办了，查源码

 private void start(boolean playBackwards) {
        if (Looper.myLooper() == null) {
            throw new AndroidRuntimeException("Animators may only be run on Looper threads");
        }
        mReversing = playBackwards;
        mSelfPulse = !mSuppressSelfPulseRequested;
        // Special case: reversing from seek-to-0 should act as if not seeked at all.
        if (playBackwards && mSeekFraction != -1 && mSeekFraction != 0) {
            if (mRepeatCount == INFINITE) {
                // Calculate the fraction of the current iteration.
                float fraction = (float) (mSeekFraction - Math.floor(mSeekFraction));
                mSeekFraction = 1 - fraction;
            } else {
                mSeekFraction = 1 + mRepeatCount - mSeekFraction;
            }
        }
        mStarted = true;
        mPaused = false;
        mRunning = false;
        mAnimationEndRequested = false;
        // Resets mLastFrameTime when start() is called, so that if the animation was running,
        // calling start() would put the animation in the
        // started-but-not-yet-reached-the-first-frame phase.
        mLastFrameTime = -1;
        mFirstFrameTime = -1;
        mStartTime = -1;
        addAnimationCallback(0);

        if (mStartDelay == 0 || mSeekFraction >= 0 || mReversing) {
            // If there's no start delay, init the animation and notify start listeners right away
            // to be consistent with the previous behavior. Otherwise, postpone this until the first
            // frame after the start delay.
            startAnimation();
            if (mSeekFraction == -1) {
                // No seek, start at play time 0. Note that the reason we are not using fraction 0
                // is because for animations with 0 duration, we want to be consistent with pre-N
                // behavior: skip to the final value immediately.
                setCurrentPlayTime(0);
            } else {
                setCurrentFraction(mSeekFraction);
            }
        }
    }

检查发现在ValueAnimator start()方法中有个addAnimationCallback(0);调用，继续检查发现

private void addAnimationCallback(long delay) {
    if (!mSelfPulse) {
        return;
    }
    getAnimationHandler().addAnimationFrameCallback(this, delay);
}
/**
 * @return The {@link AnimationHandler} that will be used to schedule updates for this animator.
 * @hide
 */
public AnimationHandler getAnimationHandler() {
    return AnimationHandler.getInstance();
}

这里就发现问题了，AnimationHandler.getInstance();这个是单例获取，所以在退出Activity时，ValueAnimator没有被释放，找到问题就好办了，就在Activity或者Fragment被销毁时，主动把动画监听取消掉。最后上一下我Demo的效果图 \得意

Screenshot_20190725-090425_ZYTeacherCertification.jpg