popwindow 動畫取消奔潰報錯java.lang.NullPointerException ViewRootImpl.drawAccessibilityFocusedDrawable

現在APP中用到popwindow的地方很多，為了美化體驗效果，很多動畫的展示和取消都加上了動畫效果；下面我就來說下我遇到的問題以及解決的方法；

cancelAnimation.addAnimation(new AlphaAnimation(1.0f, 0.0f));
cancelAnimation.addAnimation(new ScaleAnimation(1, 1, 1, -1));
cancelAnimation.setDuration(executeTime);
cancelAnimation.setAnimationListener(new Animation.AnimationListener() {
    @Override
    public void onAnimationStart(Animation animation) {
        mScrollView.setVisibility(View.VISIBLE);
    }

    @Override
    public void onAnimationEnd(Animation animation) {
        mScrollView.setVisibility(View.GONE);
       
dismiss();      
        
 } @Override public void onAnimationRepeat(Animation animation) { }});      

上面我是實作了動畫延伸和漸變來取消popwindow，在動畫結束回調dismiss();

在Android 4.4以上是不會出現任何問題；但是在Android 4.1左右的版本就會在取消是奔潰：

java.lang.NullPointerException

#5367 09-20 03:38:07.999 17478 E CrashReport         at android.view.ViewRootImpl.drawAccessibilityFocusedDrawableIfNeeded(ViewRootImpl.java:2596)

#5368 09-20 03:38:07.999 17478 E CrashReport         at android.view.ViewRootImpl.onHardwarePostDraw(ViewRootImpl.java:2183)

#5369 09-20 03:38:07.999 17478 E CrashReport         at android.view.HardwareRenderer$GlRenderer.draw(HardwareRenderer.java:1233)

#5370 09-20 03:38:07.999 17478 E CrashReport         at android.view.ViewRootImpl.draw(ViewRootImpl.java:2420)

#5371 09-20 03:38:07.999 17478 E CrashReport         at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2274)

檢視網上說的是popwindow調用dismiss()方法時報錯；我了解為時在動畫結束回調時Android4.1版本的是在子線程回調；

是以在調用dismiss();時我們加上handle試下讓它在主線程執行；

cancelAnimation.addAnimation(new AlphaAnimation(1.0f, 0.0f));
cancelAnimation.addAnimation(new ScaleAnimation(1, 1, 1, -1));
cancelAnimation.setDuration(executeTime);
cancelAnimation.setAnimationListener(new Animation.AnimationListener() {
    @Override
    public void onAnimationStart(Animation animation) {
        mScrollView.setVisibility(View.VISIBLE);
    }

    @Override
    public void onAnimationEnd(Animation animation) {
        mScrollView.setVisibility(View.GONE);
        new Handler().post(new Runnable() {
            @Override
            public void run() {
                dismiss();
            }
        });
    }

    @Override
    public void onAnimationRepeat(Animation animation) {

    }
});      

果真加了之後再Android 4.1的手機上就不在出現奔潰了