java - Android ViewGroup 崩溃 : Attempt to read from field 'int android.view.View.mViewFlags' on a null object reference

Question

我们发现了几个后端日志监控报告的此类崩溃案例。崩溃似乎与特定的 UX 故障无关。而且从报告中看，没有迹象表明我们自己的类(class)是如何参与的(没有任何我们的类(class)名称的迹象)。以下是典型崩溃的示例:

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) 

有谁知道是否有针对 Android 代码的相关错误记录？

Answer 1

可能的解决方案

我也有同样的问题。我设置了一个 animation 并在 onAnimationEnd 中删除了已经动画的对象，这是问题开始的时候。我所做的是设置一个 asynchronous Runnable 在动画停止后等待 100 毫秒，然后再移除动画对象:

之前动画的对象是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);
}

干杯