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Android sendOrderedBroadcast

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今天遇到一个 monkey 测试中发现的 sendOrderedBroadcast fail 的问题。记录一下。

错误 log 如下：

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Shutting down VM
07-04 06:11:24.319 W/dalvikvm(23361): threadid=1: thread exiting with uncaught exception (group=0x415a8898)
07-04 06:11:24.319 W/BroadcastQueue(  937): Failure sending broadcast Intent { act=android.intent.action.QUERY_PACKAGE_RESTART dat=package:com.cootek.smartinputv5.language.cangjie flg=0x10 (has extras) }
07-04 06:11:24.319 W/BroadcastQueue(  937): android.os.DeadObjectException
07-04 06:11:24.319 W/BroadcastQueue(  937):   at android.os.BinderProxy.transact(Native Method)
07-04 06:11:24.319 W/BroadcastQueue(  937):   at android.content.IIntentReceiver$Stub$Proxy.performReceive(IIntentReceiver.java:124)
07-04 06:11:24.319 W/BroadcastQueue(  937):   at com.android.server.am.BroadcastQueue.performReceiveLocked(BroadcastQueue.java:376)
07-04 06:11:24.319 W/BroadcastQueue(  937):   at com.android.server.am.BroadcastQueue.deliverToRegisteredReceiverLocked(BroadcastQueue.java:449)
07-04 06:11:24.319 W/BroadcastQueue(  937):   at com.android.server.am.BroadcastQueue.processNextBroadcast(BroadcastQueue.java:656)
07-04 06:11:24.319 W/BroadcastQueue(  937):   at com.android.server.am.ActivityManagerService.finishReceiver(ActivityManagerService.java:12451)
07-04 06:11:24.319 W/BroadcastQueue(  937):   at android.content.BroadcastReceiver$PendingResult.sendFinished(BroadcastReceiver.java:419)
07-04 06:11:24.319 W/BroadcastQueue(  937):   at android.content.BroadcastReceiver$PendingResult.finish(BroadcastReceiver.java:395)
07-04 06:11:24.319 W/BroadcastQueue(  937):   at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:780)
07-04 06:11:24.319 W/BroadcastQueue(  937):   at android.os.Handler.handleCallback(Handler.java:730)
07-04 06:11:24.319 W/BroadcastQueue(  937):   at android.os.Handler.dispatchMessage(Handler.java:92)
07-04 06:11:24.319 W/BroadcastQueue(  937):   at android.os.Looper.loop(Looper.java:137)
07-04 06:11:24.319 W/BroadcastQueue(  937):   at com.android.server.ServerThread.run(SystemServer.java:1066)

07-04 06:11:24.329 E/AndroidRuntime(23361): FATAL EXCEPTION: main
07-04 06:11:24.329 E/AndroidRuntime(23361): java.lang.RuntimeException: Error receiving broadcast Intent { act=android.intent.action.QUERY_PACKAGE_RESTART dat=package:com.cootek.smartinputv5.language.cangjie flg=0x10 (has extras) } in com.android.settings.applications.InstalledAppDetails$2@42070e38
07-04 06:11:24.329 E/AndroidRuntime(23361):   at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:773)
07-04 06:11:24.329 E/AndroidRuntime(23361):   at android.os.Handler.handleCallback(Handler.java:730)
07-04 06:11:24.329 E/AndroidRuntime(23361):   at android.os.Handler.dispatchMessage(Handler.java:92)
07-04 06:11:24.329 E/AndroidRuntime(23361):   at android.os.Looper.loop(Looper.java:137)
07-04 06:11:24.329 E/AndroidRuntime(23361):   at android.app.ActivityThread.main(ActivityThread.java:5136)
07-04 06:11:24.329 E/AndroidRuntime(23361):   at java.lang.reflect.Method.invokeNative(Native Method)
07-04 06:11:24.329 E/AndroidRuntime(23361):   at java.lang.reflect.Method.invoke(Method.java:525)
07-04 06:11:24.329 E/AndroidRuntime(23361):   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
07-04 06:11:24.329 E/AndroidRuntime(23361):   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
07-04 06:11:24.329 E/AndroidRuntime(23361):   at dalvik.system.NativeStart.main(Native Method)
07-04 06:11:24.329 E/AndroidRuntime(23361): Caused by: java.lang.NullPointerException
07-04 06:11:24.329 E/AndroidRuntime(23361):   at com.android.settings.applications.InstalledAppDetails$2.onReceive(InstalledAppDetails.java:1225)
07-04 06:11:24.329 E/AndroidRuntime(23361):   at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:763)
07-04 06:11:24.329 E/AndroidRuntime(23361):   ... 9 more
07-04 06:11:24.329 I/ActivityManager(  937): Notify an ApplicationCrash

查看下代码:

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1218     private final BroadcastReceiver mCheckKillProcessesReceiver = new BroadcastReceiver() {
1219         @Override
1220         public void onReceive(Context context, Intent intent) {
1221             updateForceStopButton(getResultCode() != Activity.RESULT_CANCELED);
1222
1223             Intent i = new Intent("qualcomm.android.LEDFlashlight.processKilled");
1224             i.putExtra(Intent.EXTRA_PACKAGES, mAppEntry.info.packageName);
1225             getActivity().sendStickyBroadcast(i);
1226         }
1227     };

可以看出 NullPointerException 的直接原因是 getActivity 失败了～

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1225             getActivity().sendStickyBroadcast(i);

可是这个怎么会失败呢？

Stack Overflow 上搜索到的 解释 :

I can see this happening if the component that called sendOrderedBroadcast() was destroyed prior to the broadcast winding its way back to the supplied instance of the BroadcastReceiver anonymous subclass.

这个解释说是因为 sendOrderedBroadcast() 的组件在 broadcast 还没有回调到这个匿名内部类的实例 mCheckKillProcessesReceiver 的时候就已经 destroy 了。

虽然我没有亲自验证，但是有两个问题：

  1. 如果 component 已经 destroy 了，按照 Android 的机制，那么 intent 过来的时候应该重新构造这个 component 才对，那么 destroy 又有什么关系呢？
  2. 这个匿名内部类的实例化是怎么完成的？ 实例化的时候是否正确的创建了 Context 信息？

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