Android ViewGroup 충돌 : null 개체 참조의 'int android.view.View.mViewFlags'필드에서 읽기 시도

Android ViewGroup 충돌 : null 개체 참조의 'int android.view.View.mViewFlags'필드에서 읽기 시도

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백엔드 로깅 모니터링에서보고 된 이러한 종류의 충돌에 대한 몇 가지 사례를 발견했습니다. 충돌이 특정 UX 실패와 관련이없는 것 같습니다. 그리고 보고서에서 우리 자신의 수업이 어떻게 관련되어 있는지에 대한 흔적이 없습니다 (우리 수업 이름의 흔적이 없음). 다음은 일반적인 충돌의 예입니다.

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:3357) 
at android.view.View.updateDisplayListIfDirty(View.java:14288) 
at android.view.View.getDisplayList(View.java:14315) 
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3549) 
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3528) 
at android.view.View.updateDisplayListIfDirty(View.java:14253) 
at android.view.View.getDisplayList(View.java:14315) 
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3549) 
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3528) 
at android.view.View.updateDisplayListIfDirty(View.java:14253) 
at android.view.View.getDisplayList(View.java:14315) 
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3549) 
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3528) 
at android.view.View.updateDisplayListIfDirty(View.java:14253) 
at android.view.View.getDisplayList(View.java:14315) 
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3549) 
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3528) 
at android.view.View.updateDisplayListIfDirty(View.java:14253) 
at android.view.View.getDisplayList(View.java:14315) 
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3549) 
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3528) 
at android.view.View.updateDisplayListIfDirty(View.java:14253) 
at android.view.View.getDisplayList(View.java:14315) 
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3549) 
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3528) 
at android.view.View.updateDisplayListIfDirty(View.java:14253) 
at android.view.View.getDisplayList(View.java:14315) 
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3549) 
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3528) 
at android.view.View.updateDisplayListIfDirty(View.java:14253) 
at android.view.View.getDisplayList(View.java:14315) 
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3549) 
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3528) 
at android.view.View.updateDisplayListIfDirty(View.java:14253) 
at android.view.View.getDisplayList(View.java:14315) 
at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3549) 
at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3528) 
at android.view.View.updateDisplayListIfDirty(View.java:14253) 
at android.view.View.getDisplayList(View.java:14315) 
at android.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:273) 
at android.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:279) 
at android.view.ThreadedRenderer.draw(ThreadedRenderer.java:318) 
at android.view.ViewRootImpl.draw(ViewRootImpl.java:2561) 
at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2377) 
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2007) 
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1086) 
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6453) 
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:846) 
at android.view.Choreographer.doCallbacks(Choreographer.java:647) 
at android.view.Choreographer.doFrame(Choreographer.java:601) 
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:829) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:135) 
at android.app.ActivityThread.main(ActivityThread.java:5254) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:927) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:713) 

Android 코드에 대해 기록 된 관련 버그가 있는지 아는 사람이 있습니까?

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가능한 해결책

나는 이와 같은 문제가 있었다. I 설치 animation과에서 onAnimationEnd내가 문제가 시작했을 때 어떤 애니메이션되었던 개체를 제거했다. 내가 한 일은 애니메이션이 중지 된 후 애니메이션 개체를 제거하기 전에 100 밀리 초를 기다리 도록 비동기 Runnable 를 설정하는 것입니다.

이전에 애니메이션 된 개체는 this._loader

private void removeLoader() {
    final ContentContainer self = this; // "CustomContainer" needs to match the type of `this`
    Handler h = new Handler();
    h.postAtTime(new Runnable() {
        @Override
        public void run() {
            MainActivity.instance.runOnUiThread(new Runnable() { 
                @Override
                public void run() {
                    try {
                        if(self._loader == null) {
                            // there is no loader. quit now while you still have the chance!!
                            return;
                        }
                        while(self._loader.getParent() != null) {
                            removeView(self._loader);
                        }
                    } catch(Exception e) {
                        Crashlytics.logException(e);
                        e.printStackTrace();
                    }

                    self._loader = null;
                }
            });
        }
    }, 100);
}

Cheers

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I was facing same problem. I resolved with Handler.

new Handler(Looper.getMainLooper()).post(new Runnable() {
                @Override
                public void run() {
                   // remove fragment from here
                }
            });

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The problem is in the ViewGroup's dispatchDraw() method. This method tries to draw all the ViewGroup's children. When a child is null, you get an exception, which most likely comes from this line: if ((child.mViewFlags & VISIBILITY_MASK) == VISIBLE) { (notice the mViewFlags).

So the problem is that one of your views, somewhere, is not properly initialized. I'm afraid that's the best I can do.

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We started getting this error unexpectedly too. It was tracked down to fragment animations being the issue. More specifically using custom animations with replace() in a fragment transaction when the app is built against Local Maven repository for Support Libraries rev > 26.

Possible solution

Downgrade Local Maven repository for Support Libraries to rev 26. See here

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Possible cause: I was having the exact same issue. It turned out it started to happen when I added code to modify the view tree within onDraw() call. To be specific, I removed a view with children in my derived onDraw() when certain conditions were met. I now believe this is a bad thing to do, probably because the platform is trying to draw views that I have now removed from the view tree. I resolved the issue by posting the deletion with Runnable to happen after the call to onDraw() has finished.

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Override dispatchDraw method and put in it a try/catch block, like this:

public void dispatchDraw(Canvas c)
    {
        try
        {
            super.dispatchDraw(c);
            return;

        }
        catch(Exception exception)
        {
            return;
        }
    }

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Even though the exception is common, the causing source is uncommon and occurs when you have so many dynamic views. Sometimes scrolling in the Instagram page cause this exception. However, if you look deep into that, the hardware problem may come to be an issue. So just handle(catch) the issue.

참고URL : https://stackoverflow.com/questions/33242776/android-viewgroup-crash-attempt-to-read-from-field-int-android-view-view-mview