一：什么是ANR

ANR:Application Not Responding，即应用无响应

二：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

三：KeyDispatchTimeout

Akey 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

//How long we wait until we timeout on key dispatching.

staticfinal int KEY_DISPATCHING_TIMEOUT = 5*1000

四：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)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

五：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

六：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

七:如何去分析ANR

先看个LOG:   

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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：

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-----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

八：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 */

九：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?）

十：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：

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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：

 

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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:

 

案例2：关键词:在UI线程进行网络数据的读写

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

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：

    

案例3：关键词：Memoryleak/Thread leak

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

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