Android - 如何调查 ANR? [英] Android - how do I investigate an ANR?

问题描述

有没有办法找出我的应用程序在哪里抛出 ANR(应用程序无响应).我查看了/data 中的 traces.txt 文件，我看到了我的应用程序的跟踪.这是我在跟踪中看到的.

Is there a way of finding out where my app threw an ANR (Application Not Responding). I took a look at the traces.txt file in /data and I see a trace for my application. This is what I see in the trace.

DALVIK THREADS:
"main" prio=5 tid=3 TIMED_WAIT
  | group="main" sCount=1 dsCount=0 s=0 obj=0x400143a8
  | sysTid=691 nice=0 sched=0/0 handle=-1091117924
  at java.lang.Object.wait(Native Method)
  - waiting on <0x1cd570> (a android.os.MessageQueue)
  at java.lang.Object.wait(Object.java:195)
  at android.os.MessageQueue.next(MessageQueue.java:144)
  at android.os.Looper.loop(Looper.java:110)
  at android.app.ActivityThread.main(ActivityThread.java:3742)
  at java.lang.reflect.Method.invokeNative(Native Method)
  at java.lang.reflect.Method.invoke(Method.java:515)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:497)
  at dalvik.system.NativeStart.main(Native Method)

"Binder Thread #3" prio=5 tid=15 NATIVE
  | group="main" sCount=1 dsCount=0 s=0 obj=0x434e7758
  | sysTid=734 nice=0 sched=0/0 handle=1733632
  at dalvik.system.NativeStart.run(Native Method)

"Binder Thread #2" prio=5 tid=13 NATIVE
  | group="main" sCount=1 dsCount=0 s=0 obj=0x433af808
  | sysTid=696 nice=0 sched=0/0 handle=1369840
  at dalvik.system.NativeStart.run(Native Method)

"Binder Thread #1" prio=5 tid=11 NATIVE
  | group="main" sCount=1 dsCount=0 s=0 obj=0x433aca10
  | sysTid=695 nice=0 sched=0/0 handle=1367448
  at dalvik.system.NativeStart.run(Native Method)

"JDWP" daemon prio=5 tid=9 VMWAIT
  | group="system" sCount=1 dsCount=0 s=0 obj=0x433ac2a0
  | sysTid=694 nice=0 sched=0/0 handle=1367136
  at dalvik.system.NativeStart.run(Native Method)

"Signal Catcher" daemon prio=5 tid=7 RUNNABLE
  | group="system" sCount=0 dsCount=0 s=0 obj=0x433ac1e8
  | sysTid=693 nice=0 sched=0/0 handle=1366712
  at dalvik.system.NativeStart.run(Native Method)

"HeapWorker" daemon prio=5 tid=5 VMWAIT
  | group="system" sCount=1 dsCount=0 s=0 obj=0x4253ef88
  | sysTid=692 nice=0 sched=0/0 handle=1366472
  at dalvik.system.NativeStart.run(Native Method)

----- end 691 -----

我怎样才能找出问题所在?trace中的方法都是SDK方法.

How can I find out where the problem is? The methods in the trace are all SDK methods.

推荐答案

当在主"线程中发生一些长时间的操作时会发生 ANR.这是事件循环线程，如果它很忙，Android 将无法处理应用程序中的任何其他 GUI 事件，从而引发 ANR 对话框.

An ANR happens when some long operation takes place in the "main" thread. This is the event loop thread, and if it is busy, Android cannot process any further GUI events in the application, and thus throws up an ANR dialog.

现在，在你贴出的trace中，主线程似乎运行良好，没有问题.它在 MessageQueue 中空闲，等待另一条消息进来.在您的情况下，ANR 可能是一个更长的操作，而不是永久阻塞线程的操作，因此事件线程在操作完成后恢复，并且您的跟踪通过在 ANR 之后.

Now, in the trace you posted, the main thread seems to be doing fine, there is no problem. It is idling in the MessageQueue, waiting for another message to come in. In your case the ANR was likely a longer operation, rather than something that blocked the thread permanently, so the event thread recovered after the operation finished, and your trace went through after the ANR.

如果它是一个永久块(例如死锁获取一些锁)，则检测 ANR 发生的位置很容易，但如果它只是临时延迟，则更难.首先，检查您的代码并寻找易受攻击的地方和长时间运行的操作.示例可能包括在事件线程中使用套接字、锁、线程休眠和其他阻塞操作.您应该确保这些都发生在单独的线程中.如果没有任何问题，请使用 DDMS 并启用线程视图.这会显示您的应用程序中的所有线程，类似于您拥有的跟踪.重现ANR，同时刷新主线程.这应该可以准确地向您显示 ANR 发生时的情况

Detecting where ANRs happen is easy if it is a permanent block (deadlock acquiring some locks for instance), but harder if it's just a temporary delay. First, go over your code and look for vunerable spots and long running operations. Examples may include using sockets, locks, thread sleeps, and other blocking operations from within the event thread. You should make sure these all happen in separate threads. If nothing seems the problem, use DDMS and enable the thread view. This shows all the threads in your application similar to the trace you have. Reproduce the ANR, and refresh the main thread at the same time. That should show you precisely whats going on at the time of the ANR

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