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：

01 public 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：

01 02-27 10:03:56.122: DEBUG/StrictMode(16210): StrictMode policy violation; ~duration=696 ms: android.os.StrictMode$StrictModeDiskReadViolation: policy=23 violation=2
02 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.os.StrictMode$AndroidBlockGuardPolicy.onReadFromDisk(StrictMode.java:745)
03 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at dalvik.system.BlockGuard$WrappedFileSystem.open(BlockGuard.java:228)
04 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at java.io.FileOutputStream.<init>(FileOutputStream.java:94)
05 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at java.io.FileOutputStream.<init>(FileOutputStream.java:66)
06 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at java.io.FileWriter.<init>(FileWriter.java:42)
07 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at org.zelos.asm.main.writeFile(main.java:30)
08 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at org.zelos.asm.main.onCreate(main.java:19)
09 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
10 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
11 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
12 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
13 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
14 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.os.Handler.dispatchMessage(Handler.java:99)
15 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.os.Looper.loop(Looper.java:123)
16 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at android.app.ActivityThread.main(ActivityThread.java:3683)
17 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at java.lang.reflect.Method.invokeNative(Native Method)
18 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at java.lang.reflect.Method.invoke(Method.java:507)
19 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
20 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
21 02-27 10:03:56.122: DEBUG/StrictMode(16210):     at dalvik.system.NativeStart.main(Native Method)
22 02-27 10:03:56.162: DEBUG/StrictMode(16210): StrictMode policy violation; ~duration=619 ms: android.os.StrictMode$StrictModeDiskWriteViolation: policy=23 violation=1
23 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.os.StrictMode$AndroidBlockGuardPolicy.onWriteToDisk(StrictMode.java:732)
24 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at dalvik.system.BlockGuard$WrappedFileSystem.open(BlockGuard.java:230)
25 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at java.io.FileOutputStream.<init>(FileOutputStream.java:94)
26 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at java.io.FileOutputStream.<init>(FileOutputStream.java:66)
27 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at java.io.FileWriter.<init>(FileWriter.java:42)
28 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at org.zelos.asm.main.writeFile(main.java:30)
29 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at org.zelos.asm.main.onCreate(main.java:19)
30 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
31 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
32 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
33 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
34 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
35 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.os.Handler.dispatchMessage(Handler.java:99)
36 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.os.Looper.loop(Looper.java:123)
37 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at android.app.ActivityThread.main(ActivityThread.java:3683)
38 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at java.lang.reflect.Method.invokeNative(Native Method)
39 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at java.lang.reflect.Method.invoke(Method.java:507)
40 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
41 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
42 02-27 10:03:56.162: DEBUG/StrictMode(16210):     at dalvik.system.NativeStart.main(Native Method)