什么是ANR？

1	ANR:Application Not Responding，即应用无响应

ANR的类型

ANR一般有三种类型：

1. KeyDispatchTimeout(5 seconds) --主要类型按键或触摸事件在特定时间内无响应
2. BroadcastTimeout(10 seconds) --BroadcastReceiver在特定时间内无法处理完成
3. ServiceTimeout(20 seconds) --小概率类型 Service在特定的时间内无法处理完成

KeyDispatchTimeout

A key or touch event was not dispatched within the specified time（按键或触摸事件在特定时间内无响应）
具体的超时时间的定义在framework下的ActivityManagerService.java

1 2	// How long we wait until we timeout on key dispatching. static final int KEY_DISPATCHING_TIMEOUT = 5*1000;

为什么会超时呢？

超时时间的计数一般是从按键分发给app开始。超时的原因一般有两种：

1
2
3

1. 当前的事件没有机会得到处理（即UI线程正在处理前一个事件，没有及时的完成或者looper被某种原因阻塞住了）
2. 当前的事件正在处理，但没有及时完成

如何避免KeyDispatchTimeout

1. UI线程尽量只做跟UI相关的工作
2. 耗时的工作（比如数据库操作，I/O，连接网络或者别的有可能阻碍UI线程的操作）把它放入单独的线程处理
3. 尽量用Handler来处理UIthread和别的thread之间的交互

UI线程

说了那么多的UI线程，那么哪些属于UI线程呢？

UI线程主要包括如下：

1. Activity:onCreate(), onResume(), onDestroy(), onKeyDown(), onClick(),etc
2. AsyncTask: onPreExecute(), onProgressUpdate(), onPostExecute(), onCancel,etc
3. Mainthread handler: handleMessage(), post*(runnable r), etc
4. other

如何去分析ANR

先看个LOG：

04-01 13:12:11.572 I/InputDispatcher( 220): Application is not responding:Window{2b263310com.android.email/com.android.email.activity.SplitScreenActivitypaused=false}.
5009.8ms since event, 5009.5ms since waitstarted
04-0113:12:11.572 I/WindowManager( 220): Input event
dispatching timedout sending
tocom.android.email/com.android.email.activity.SplitScreenActivity
04-01 13:12:14.123 I/Process( 220): Sending signal. PID: 21404 SIG: 3---发生ANR的时间和生成trace.txt的时间
04-01 13:12:14.123 I/dalvikvm(21404):threadid=4: reacting to
signal 3
……
04-0113:12:15.872 E/ActivityManager( 220): ANR in
com.android.email(com.android.email/.activity.SplitScreenActivity)
04-0113:12:15.872 E/ActivityManager( 220):
Reason:keyDispatchingTimedOut
04-0113:12:15.872 E/ActivityManager( 220): Load: 8.68 / 8.37 / 8.53
04-0113:12:15.872 E/ActivityManager( 220): CPUusage from 4361ms to 699ms ago ----CPU在ANR发生前的使用情况
04-0113:12:15.872 E/ActivityManager( 220): 5.5%21404/com.android.email: 1.3% user + 4.1% kernel / faults:
10 minor
04-0113:12:15.872 E/ActivityManager( 220): 4.3%220/system_server: 2.7% user + 1.5% kernel / faults: 11
minor 2 major
04-0113:12:15.872 E/ActivityManager( 220): 0.9%52/spi_qsd.0: 0% user + 0.9% kernel
04-0113:12:15.872 E/ActivityManager( 220): 0.5%65/irq/170-cyttsp-: 0% user + 0.5% kernel
04-0113:12:15.872 E/ActivityManager( 220): 0.5%296/com.android.systemui: 0.5% user + 0% kernel
04-0113:12:15.872 E/ActivityManager( 220): 100%TOTAL: 4.8% user + 7.6% kernel + 87% iowait
04-0113:12:15.872 E/ActivityManager( 220): CPUusage from 3697ms to 4223ms later:-- ANR后CPU的使用量
04-0113:12:15.872 E/ActivityManager( 220): 25%21404/com.android.email: 25% user + 0% kernel / faults: 191 minor
04-0113:12:15.872 E/ActivityManager( 220): 16% 21603/__eas(par.hakan: 16% user + 0% kernel
04-0113:12:15.872 E/ActivityManager( 220): 7.2% 21406/GC: 7.2% user + 0% kernel
04-0113:12:15.872 E/ActivityManager( 220): 1.8% 21409/Compiler: 1.8% user + 0% kernel
04-0113:12:15.872 E/ActivityManager( 220): 5.5%220/system_server: 0% user + 5.5% kernel / faults: 1 minor
04-0113:12:15.872 E/ActivityManager( 220): 5.5% 263/InputDispatcher: 0% user + 5.5% kernel
04-0113:12:15.872 E/ActivityManager( 220): 32%TOTAL: 28% user + 3.7% kernel

从LOG可以看出ANR的类型，CPU的使用情况，如果CPU使用量接近100%，说明当前设备很忙，有可能是CPU饥饿导致了ANR

如果CPU使用量很少，说明主线程被BLOCK了

如果IOwait很高，说明ANR有可能是主线程在进行I/O操作造成的

除了看LOG，解决ANR还得需要trace.txt文件，

如何获取呢？可以用如下命令获取

$chmod 777 /data/anr
$rm /data/anr/traces.txt
$ps
$kill -3 PID

adbpull data/anr/traces.txt ./mytraces.txt

从trace.txt文件，看到最多的是如下的信息：

-----pid 21404 at 2011-04-01 13:12:14 -----
Cmdline: com.android.email
DALVIK THREADS:
(mutexes: tll=0tsl=0 tscl=0 ghl=0 hwl=0 hwll=0)
"main" prio=5 tid=1NATIVE
| group="main" sCount=1 dsCount=0obj=0x2aad2248 self=0xcf70
| sysTid=21404 nice=0 sched=0/0cgrp=[fopen-error:2]
handle=1876218976
atandroid.os.MessageQueue.nativePollOnce(Native Method)
atandroid.os.MessageQueue.next(MessageQueue.java:119)
atandroid.os.Looper.loop(Looper.java:110)
at android.app.ActivityThread.main(ActivityThread.java:3688)
at java.lang.reflect.Method.invokeNative(Native Method)
atjava.lang.reflect.Method.invoke(Method.java:507)
atcom.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:624)
at dalvik.system.NativeStart.main(Native Method)

说明主线程在等待下条消息进入消息队列

Thread状态

ThreadState (defined at “dalvik/vm/thread.h “)
THREAD_UNDEFINED = -1, /* makes enum compatible with int32_t */
THREAD_ZOMBIE = 0, /* TERMINATED */
THREAD_RUNNING = 1, /* RUNNABLE or running now */
THREAD_TIMED_WAIT = 2, /* TIMED_WAITING in Object.wait() */
THREAD_MONITOR = 3, /* BLOCKED on a monitor */
THREAD_WAIT = 4, /* WAITING in Object.wait() */
THREAD_INITIALIZING= 5, /* allocated, not yet running */
THREAD_STARTING = 6, /* started, not yet on thread list */
THREAD_NATIVE = 7, /* off in a JNI native method */
THREAD_VMWAIT = 8, /* waiting on a VM resource */
THREAD_SUSPENDED = 9, /* suspended, usually by GC or debugger */

如何调查并解决ANR

1. 首先分析log
2. 从trace.txt文件查看调用stack.
3. 看代码
4. 仔细查看ANR的成因（iowait?block?memoryleak?）

案例

案例1：关键词:ContentResolver in AsyncTask onPostExecute, high iowait

原因：IOWait很高，说明当前系统在忙于I/O，因此数据库操作被阻塞

原来：

final Message message=Message.restoreMessageWithId(mProviderContext,messageId);
    if(message==null){
    return;
}
Account account=Account.restoreAccountWithId(mProviderContext,message.mAccountKey);
if(account==null){
    return;//isMessagingController returns false for null, but let's make itclear.
}
if(isMessagingController(account)){
    new Thread(){
        @Override
        public void run(){
        mLegacyController.processPendingActions(message.mAccountKey);
    }}.start();
}

解决后：

newThread() {
    finalMessagemessage=Message.restoreMessageWithId(mProviderContext,messageId);
    if(message==null){
        return;
    }
    Accountaccount=Account.restoreAccountWithId(mProviderContext,message.mAccountKey);
    if(account==null){
        return;//isMessagingController returns false for null, but let's make itclear.
    }
    if(isMessagingController(account)) {
        mLegacyController.processPendingActions(message.mAccountKey);
    }
}.start();

关于AsyncTask:http://developer.android.com/reference/android/os/AsyncTask.html

案例2：关键词:在UI线程进行网络数据的读写

ANRin process: com.android.mediascape:PhotoViewer (last incom.android.mediascape:PhotoViewer)
    Annotation:keyDispatchingTimedOut
    CPU usage:
    Load: 6.74 / 6.89 / 6.12
    CPUusage from 8254ms to 3224ms ago:
    ovider.webmedia: 4% = 4% user +0% kernel / faults: 68 minor
    system_server: 2% = 1% user + 0%kernel / faults: 18 minor
    re-initialized>: 0% = 0% user + 0%kernel / faults: 50 minor
    events/0: 0% = 0% user + 0%kernel
    TOTAL:7% = 6% user + 1% kernel
    DALVIKTHREADS:
    ""main"" prio=5 tid=3 NATIVE
    |group=""main"" sCount=1 dsCount=0 s=Yobj=0x4001b240 self=0xbda8
    | sysTid=2579 nice=0 sched=0/0cgrp=unknown handle=-1343993184
    atorg.apache.harmony.luni.platform.OSNetworkSystem.receiveStreamImpl(NativeMethod)
    atorg.apache.harmony.luni.platform.OSNetworkSystem.receiveStream(OSNetworkSystem.java:478)
    atorg.apache.harmony.luni.net.PlainSocketImpl.read(PlainSocketImpl.java:565)
    atorg.apache.harmony.luni.net.SocketInputStream.read(SocketInputStream.java:87)
    atorg.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnection$LimitedInputStream.read(HttpURLConnection.java:303)
    atjava.io.InputStream.read(InputStream.java:133)
    atjava.io.BufferedInputStream.fillbuf(BufferedInputStream.java:157)
    atjava.io.BufferedInputStream.read(BufferedInputStream.java:346)
    atandroid.graphics.BitmapFactory.nativeDecodeStream(Native Method)
    atandroid.graphics.BitmapFactory.decodeStream(BitmapFactory.java:459)
    atcom.android.mediascape.activity.PhotoViewerActivity.getPreviewImage(PhotoViewerActivity.java:4465)
    atcom.android.mediascape.activity.PhotoViewerActivity.dispPreview(PhotoViewerActivity.java:4406)
    atcom.android.mediascape.activity.PhotoViewerActivity.access$6500(PhotoViewerActivity.java:125)
    atcom.android.mediascape.activity.PhotoViewerActivity$33$1.run(PhotoViewerActivity.java:4558)
    atandroid.os.Handler.handleCallback(Handler.java:587)
    atandroid.os.Handler.dispatchMessage(Handler.java:92)
    atandroid.os.Looper.loop(Looper.java:123)
    atandroid.app.ActivityThread.main(ActivityThread.java:4370)
    atjava.lang.reflect.Method.invokeNative(Native Method)
    atjava.lang.reflect.Method.invoke(Method.java:521)
    atcom.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
    atcom.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
    atdalvik.system.NativeStart.main(Native Method)

关于网络连接，在设计的时候可以设置个timeout的时间或者放入独立的线程来处理。

关于Handler的问题，可以参考：http://developer.android.com/reference/android/os/Handler.html

案例3：关键词：Memoryleak/Thread leak

11-1621:41:42.560 I/ActivityManager( 1190): ANR in process:android.process.acore (last in android.process.acore)
    11-1621:41:42.560 I/ActivityManager( 1190): Annotation:keyDispatchingTimedOut
    11-16 21:41:42.560 I/ActivityManager(1190): CPU usage:
    11-16 21:41:42.560 I/ActivityManager( 1190):Load: 11.5 / 11.1 / 11.09
    11-16 21:41:42.560 I/ActivityManager(1190): CPU usage from 9046ms to 4018ms ago:
    11-16 21:41:42.560I/ActivityManager( 1190): d.process.acore:98%= 97% user + 0% kernel / faults: 1134 minor
    11-16 21:41:42.560I/ActivityManager( 1190): system_server: 0% = 0% user + 0% kernel /faults: 1 minor
    11-16 21:41:42.560 I/ActivityManager( 1190): adbd:0% = 0% user + 0% kernel
    11-16 21:41:42.560 I/ActivityManager(1190): logcat: 0% = 0% user + 0% kernel
    11-16 21:41:42.560I/ActivityManager( 1190): TOTAL:100% = 98% user + 1% kernel
    Cmdline: android.process.acore
    DALVIK THREADS:
    "main"prio=5 tid=3 VMWAIT
    |group="main" sCount=1 dsCount=0 s=N obj=0x40026240self=0xbda8
    | sysTid=1815 nice=0 sched=0/0 cgrp=unknownhandle=-1344001376
    atdalvik.system.VMRuntime.trackExternalAllocation(NativeMethod)
    atandroid.graphics.Bitmap.nativeCreate(Native Method)
    atandroid.graphics.Bitmap.createBitmap(Bitmap.java:468)
    atandroid.view.View.buildDrawingCache(View.java:6324)
    atandroid.view.View.getDrawingCache(View.java:6178)
    atandroid.view.ViewGroup.drawChild(ViewGroup.java:1541)
    ……
    atcom.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:1830)
    atandroid.view.ViewRoot.draw(ViewRoot.java:1349)
    atandroid.view.ViewRoot.performTraversals(ViewRoot.java:1114)
    atandroid.view.ViewRoot.handleMessage(ViewRoot.java:1633)
    atandroid.os.Handler.dispatchMessage(Handler.java:99)
    atandroid.os.Looper.loop(Looper.java:123)
    atandroid.app.ActivityThread.main(ActivityThread.java:4370)
    atjava.lang.reflect.Method.invokeNative(Native Method)
    atjava.lang.reflect.Method.invoke(Method.java:521)
    atcom.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
    atcom.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
    atdalvik.system.NativeStart.main(Native Method)
    "Thread-408"prio=5 tid=329 WAIT
    |group="main" sCount=1 dsCount=0 s=N obj=0x46910d40self=0xcd0548
    | sysTid=10602 nice=0 sched=0/0 cgrp=unknownhandle=15470792
    at java.lang.Object.wait(Native Method)
    -waiting on <0x468cd420> (a java.lang.Object)
    atjava.lang.Object.wait(Object.java:288)
    atcom.android.dialer.CallLogContentHelper$UiUpdaterExecutor$1.run(CallLogContentHelper.java:289)
    atjava.lang.Thread.run(Thread.java:1096)

分析：

atdalvik.system.VMRuntime.trackExternalAllocation(NativeMethod)内存不足导致block在创建bitmap上

MEMINFO in pid 1360 [android.process.acore]

native dalvik other total

size: 17036 23111 N/A 40147

allocated: 16484 20675 N/A 37159

free: 296 2436 N/A 2732

解决：如果机器的内存族，可以修改虚拟机的内存为36M或更大，不过最好是复查代码，查看哪些内存没有释放

感谢

本篇博客转自于下http://www.cnblogs.com/purediy/p/3225060.html

感谢作者的总结和分享！

参考资料

http://www.cnblogs.com/purediy/p/3225060.html

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