ANDROID StrictMode 使用

ANR窗口产生的原因是多种多样的。程序的主线程因为IO读写或网络阻塞而导致被阻塞了，外部存储设备被独占了或系统负荷（load）过高（即不是自己编写的程序的问题，可能是系统或者其他第三方程序导致的问题），都有可能导致ANR窗口的出现。

从Android 2.3开始提供了一个新的类StrictMode，可以帮助开发者改进他们的Android应用，StrictMode可以用于捕捉发生在应用程序主线程 中耗时的磁盘、网络访问或函数调用，可以帮助开发者使其改进程序，使主线程处理UI和动画在磁盘读写和网络操作时变得更平滑，
避免主线程被阻塞，导致ANR窗口的发生。

下面简要说明下Android 2.3新特性StrictMode限制模式的工作方式，见下面的代码：

01public void onCreate() {

02     if (DEVELOPER_MODE) {

03         StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()

04                 .detectDiskReads()

05                 .detectDiskWrites()

06                 .detectNetwork()  // 这里可以替换为detectAll() 就包括了磁盘读写和网络I/O

07                 .penaltyLog()  //打印logcat，当然也可以定位到dropbox，通过文件保存相应的log

08                 .build());

09         StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()

10                 .detectLeakedSqlLiteObjects()//探测SQLite数据库操作

11                 .penaltyLog() //打印logcat

12                 .penaltyDeath()

13                 .build());

14     }

15     super.onCreate();

16 }

上述代码可以在Application的OnCreate中添加，这样就能在程序启动的最初一刻进行监控了。

输出log如下：

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0102-27 10:03:56.122: DEBUG/StrictMode(16210): StrictMode policy violation; ~duration=696 ms: android.os.StrictMode$StrictModeDiskReadViolation: policy=23 violation=2

0202-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.os.StrictMode$AndroidBlockGuardPolicy.onReadFromDisk(StrictMode.java:745)

0302-27 10:03:56.122: DEBUG/StrictMode(16210):     at dalvik.system.BlockGuard$WrappedFileSystem.open(BlockGuard.java:228)

0402-27 10:03:56.122: DEBUG/StrictMode(16210):     at java.io.FileOutputStream.<init>(FileOutputStream.java:94)

0502-27 10:03:56.122: DEBUG/StrictMode(16210):     at java.io.FileOutputStream.<init>(FileOutputStream.java:66)

0602-27 10:03:56.122: DEBUG/StrictMode(16210):     at java.io.FileWriter.<init>(FileWriter.java:42)

0702-27 10:03:56.122: DEBUG/StrictMode(16210):     at org.zelos.asm.main.writeFile(main.java:30)

0802-27 10:03:56.122: DEBUG/StrictMode(16210):     at org.zelos.asm.main.onCreate(main.java:19)

0902-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)

1002-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)

1102-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)

1202-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)

1302-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)

1402-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.os.Handler.dispatchMessage(Handler.java:99)

1502-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.os.Looper.loop(Looper.java:123)

1602-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.app.ActivityThread.main(ActivityThread.java:3683)

1702-27 10:03:56.122: DEBUG/StrictMode(16210):     at java.lang.reflect.Method.invokeNative(Native Method)

1802-27 10:03:56.122: DEBUG/StrictMode(16210):     at java.lang.reflect.Method.invoke(Method.java:507)

1902-27 10:03:56.122: DEBUG/StrictMode(16210):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)

2002-27 10:03:56.122: DEBUG/StrictMode(16210):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)

2102-27 10:03:56.122: DEBUG/StrictMode(16210):     at dalvik.system.NativeStart.main(Native Method)

2202-27 10:03:56.162: DEBUG/StrictMode(16210): StrictMode policy violation; ~duration=619 ms: android.os.StrictMode$StrictModeDiskWriteViolation: policy=23 violation=1

2302-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.os.StrictMode$AndroidBlockGuardPolicy.onWriteToDisk(StrictMode.java:732)

2402-27 10:03:56.162: DEBUG/StrictMode(16210):     at dalvik.system.BlockGuard$WrappedFileSystem.open(BlockGuard.java:230)

2502-27 10:03:56.162: DEBUG/StrictMode(16210):     at java.io.FileOutputStream.<init>(FileOutputStream.java:94)

2602-27 10:03:56.162: DEBUG/StrictMode(16210):     at java.io.FileOutputStream.<init>(FileOutputStream.java:66)

2702-27 10:03:56.162: DEBUG/StrictMode(16210):     at java.io.FileWriter.<init>(FileWriter.java:42)

2802-27 10:03:56.162: DEBUG/StrictMode(16210):     at org.zelos.asm.main.writeFile(main.java:30)

2902-27 10:03:56.162: DEBUG/StrictMode(16210):     at org.zelos.asm.main.onCreate(main.java:19)

3002-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)

3102-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)

3202-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)

3302-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)

3402-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)

3502-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.os.Handler.dispatchMessage(Handler.java:99)

3602-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.os.Looper.loop(Looper.java:123)

3702-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.app.ActivityThread.main(ActivityThread.java:3683)

3802-27 10:03:56.162: DEBUG/StrictMode(16210):     at java.lang.reflect.Method.invokeNative(Native Method)

3902-27 10:03:56.162: DEBUG/StrictMode(16210):     at java.lang.reflect.Method.invoke(Method.java:507)

4002-27 10:03:56.162: DEBUG/StrictMode(16210):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)

4102-27 10:03:56.162: DEBUG/StrictMode(16210):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)

4202-27 10:03:56.162: DEBUG/StrictMode(16210):     at dalvik.system.NativeStart.main(Native Method)

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