ANR问题的分析和解决

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

 

  七: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
                  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?）

 

 

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