android - 获取 NullPointerException : Attempt to read from field 'int android.view.View.mViewFlags' - Android animation

Question

我已经实现了一个动画，其中我在回收站 View 中有 ImageView ，在单击项目时我想在回收站 View 外的 ImageView 上做一些动画，这样- 我创建了一个新的 ImageView ，- 将其添加到主容器- 做了动画- 最后我将它从主容器中移除

这是回收站 View 的点击项目的代码:

代码:

final ImageView iv = new ImageView(getContext());
iv.setImageDrawable(fromView.getDrawable());
iv.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
iv.setLayoutParams(fromView.getLayoutParams());
v_mainContainer.addView(iv);

AnimationSet animatinSet = new AnimationSet(false);
animatinSet.setFillAfter(false);
animatinSet.setFillBefore(true);
animatinSet.setDuration(1500);
animatinSet.setInterpolator(new DecelerateInterpolator());

// ... rest of the animation 

animatinSet.setAnimationListener(new Animation.AnimationListener() {
    @Override
    public void onAnimationStart(Animation animation) {

    }

    @Override
    public void onAnimationEnd(Animation animation) {
        v_mainContainer.removeView(iv);
    }

    @Override
    public void onAnimationRepeat(Animation animation) {

    }
});

animatinSet.setAnimationListener(animationListner);
animatinSet.setDuration(1500);

iv.startAnimation(animatinSet);

当我在 1 个 View 上运行此动画时，它工作正常。但是，当我在同一个 View 上多次运行动画时，在运行另一个动画之前，我会收到以下错误。

错误日志:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.mbh.testApp, PID: 9628
    java.lang.NullPointerException: Attempt to read from field 'int android.view.View.mViewFlags' on a null object reference
        at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3549)
        at android.view.View.draw(View.java:17071)
        at android.view.View.updateDisplayListIfDirty(View.java:16050)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3748)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3728)
        at android.view.View.updateDisplayListIfDirty(View.java:16013)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3748)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3728)
        at android.view.View.updateDisplayListIfDirty(View.java:16013)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3748)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3728)
        at android.view.View.updateDisplayListIfDirty(View.java:16013)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3748)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3728)
        at android.view.View.updateDisplayListIfDirty(View.java:16013)
        at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3748)
        at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3728)
        at android.view.View.updateDisplayListIfDirty(View.java:16013)
        at android.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:656)
        at android.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:662)
        at android.view.ThreadedRenderer.draw(ThreadedRenderer.java:770)
        at android.view.ViewRootImpl.draw(ViewRootImpl.java:2796)
        at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2604)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2211)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1246)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6301)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:871)
        at android.view.Choreographer.doCallbacks(Choreographer.java:683)
        at android.view.Choreographer.doFrame(Choreographer.java:619)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:857)
        at android.os.Handler.handleCallback(Handler.java:751)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6077)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)

我试图在从主容器中移除 View 时放置 try-catch block ，但它并没有改变结果并且仍然出现相同的错误。

我也试过这个答案https://stackoverflow.com/a/4295570/2296787并没有解决问题

奇怪的是错误并没有告诉我异常发生的确切位置。

预先感谢您的帮助。

Answer 1

正如 @sasikumar 提到的解决方案是在真实设备 上运行测试

但我也在模拟器上解决了这个问题，方法是在动画结束监听器中删除 View 之前添加 postDelayed 并延迟 500 毫秒:

animatinSet.setAnimationListener(new Animation.AnimationListener() {
    @Override
    public void onAnimationStart(Animation animation) {
    }

    @Override
    public void onAnimationEnd(Animation animation) {
        iv.setVisibility(View.GONE);
        v_mainContainer.postDelayed(new Runnable() {
            @Override
            public void run() {
                v_mainContainer.removeView(iv);
            }
        }, 500);
    }

    @Override
    public void onAnimationRepeat(Animation animation) {
    }
});

这适用于模拟器和真实设备