IssueTracker

Dear Android Teams:
I found a bug in AniamtorSet ValueAnimator and ObjectAnimator. That's lead to Animator.onAnimationEnd() not called in some case. I upload my sample codes and you can check it.

Device: Android 14 emulator.
Steps to Reproduce or Code Sample to Reproduce:

1. Press the button.
2. Wait 1s0, the animation will be stoped.
3. Trriger gc in profiler. Finally, the AnimatorSet.onAnimationEnd() will never called.

Stack trace (if applicable):

AnimatorSet.doAnimationFrame
    AnimatorSet.pulseFrame
        ValueAnimator.pulseAnimationFrame
           ValueAnimator.doAnimationFrame
               ValueAnimator.animateBasedOnTime
                   ObjectAnimator.animateValue{
                               if (mTarget != null && target == null) {
                                   // We lost the target reference, cancel and clean up. Note: we allow null target if the
                                   /// target has never been set.
                                  cancel();
                                  return;

                    }
                   }

I found when animation playing. If the ObjectAnimation's target becomes to null. The animation will ends in animateValue(). But the animateBasedOnTime() does not cover this case.

    boolean animateBasedOnTime(long currentTime) {
        boolean done = false;
        if (mRunning) {
            final long scaledDuration = getScaledDuration();
            final float fraction = scaledDuration > 0 ?
                    (float)(currentTime - mStartTime) / scaledDuration : 1f;
            final float lastFraction = mOverallFraction;
            final boolean newIteration = (int) fraction > (int) lastFraction;
            final boolean lastIterationFinished = (fraction >= mRepeatCount + 1) &&
                    (mRepeatCount != INFINITE);
            if (scaledDuration == 0) {
                // 0 duration animator, ignore the repeat count and skip to the end
                done = true;
            } else if (newIteration && !lastIterationFinished) {
                // Time to repeat
                notifyListeners(AnimatorCaller.ON_REPEAT, false);
            } else if (lastIterationFinished) {
                done = true;
            }
            mOverallFraction = clampFraction(fraction);
            float currentIterationFraction = getCurrentIterationFraction(
                    mOverallFraction, mReversing);
            animateValue(currentIterationFraction);
        }
        return done;
    }

So the animation already ended but the animator not realize it. That's make this bug happened.

I have proposed a method to fix this bug.

    boolean animateBasedOnTime(long currentTime) {
        boolean done = false;
        if (mRunning) {
            final long scaledDuration = getScaledDuration();
            final float fraction = scaledDuration > 0 ?
                    (float)(currentTime - mStartTime) / scaledDuration : 1f;
            final float lastFraction = mOverallFraction;
            final boolean newIteration = (int) fraction > (int) lastFraction;
            final boolean lastIterationFinished = (fraction >= mRepeatCount + 1) &&
                    (mRepeatCount != INFINITE);
            if (scaledDuration == 0) {
                // 0 duration animator, ignore the repeat count and skip to the end
                done = true;
            } else if (newIteration && !lastIterationFinished) {
                // Time to repeat
                notifyListeners(AnimatorCaller.ON_REPEAT, false);
            } else if (lastIterationFinished) {
                done = true;
            }
            mOverallFraction = clampFraction(fraction);
            float currentIterationFraction = getCurrentIterationFraction(
                    mOverallFraction, mReversing);
            animateValue(currentIterationFraction);
            if (!mRunning){
                //The animation is ended by animateValue(). So return true in this case.
                done = true;
            }
        }
        return done;
    }

Do you agree with my point of view? If there is anything I haven't considered, please let me know. Thank you.