ANR視窗產生的原因是多種多樣的。程式的主線程因為IO讀寫或網路阻塞而導致被阻塞了，外部存放裝置被獨佔了或系統負荷（load）過高（即不是自己編寫的程式的問題，可能是系統或者其他第三方程式導致的問題），都有可能導致ANR視窗的出現。
從Android
2.3開始提供了一個新的類StrictMode，可以協助開發人員改進他們的Android應用，StrictMode可以用於捕捉髮生在應用程式主線程中耗時的磁碟、網路訪問或函數調用，可以協助開發人員使其改進程式，使主線程處理UI和動畫在磁碟讀寫和網路操作時變得更平滑，避免主線程被阻塞，導致ANR視窗的發生。
下面簡要說明下Android 2.3新特性StrictMode限制模式的工作方式，見下面的代碼：
publicvoid onCreate() {
if (DEVELOPER_MODE) {
StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
.detectDiskReads()
.detectDiskWrites()
.detectNetwork() // 這裡可以替換為detectAll() 就包括了磁碟讀寫和網路I/O
.penaltyLog() //列印logcat，當然也可以定位到dropbox，通過檔案儲存相應的log
.build());
StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()
.detectLeakedSqlLiteObjects() //探測SQLite資料庫操作
.penaltyLog() //列印logcat
.penaltyDeath()
.build());
}
super.onCreate();
}
上述代碼可以在Application的OnCreate中添加，這樣就能在程式啟動的最初一刻進行監控了。
輸出log如下：
02-27 10:03:56.122: DEBUG/StrictMode(16210): StrictMode policy violation; ~duration=696 ms: android.os.StrictMode$StrictModeDiskReadViolation: policy=23 violation=2
02-27 10:03:56.122: DEBUG/StrictMode(16210): at android.os.StrictMode$AndroidBlockGuardPolicy.onReadFromDisk(StrictMode.java:745)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at dalvik.system.BlockGuard$WrappedFileSystem.open(BlockGuard.java:228)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at java.io.FileOutputStream.<init>(FileOutputStream.java:94)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at java.io.FileOutputStream.<init>(FileOutputStream.java:66)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at java.io.FileWriter.<init>(FileWriter.java:42)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at org.zelos.asm.main.writeFile(main.java:30)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at org.zelos.asm.main.onCreate(main.java:19)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at android.os.Handler.dispatchMessage(Handler.java:99)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at android.os.Looper.loop(Looper.java:123)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at android.app.ActivityThread.main(ActivityThread.java:3683)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at java.lang.reflect.Method.invokeNative(Native Method)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at java.lang.reflect.Method.invoke(Method.java:507)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
02-27 10:03:56.122: DEBUG/StrictMode(16210): at dalvik.system.NativeStart.main(Native Method)
02-27 10:03:56.162: DEBUG/StrictMode(16210): StrictMode policy violation; ~duration=619 ms: android.os.StrictMode$StrictModeDiskWriteViolation: policy=23 violation=1
02-27 10:03:56.162: DEBUG/StrictMode(16210): at android.os.StrictMode$AndroidBlockGuardPolicy.onWriteToDisk(StrictMode.java:732)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at dalvik.system.BlockGuard$WrappedFileSystem.open(BlockGuard.java:230)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at java.io.FileOutputStream.<init>(FileOutputStream.java:94)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at java.io.FileOutputStream.<init>(FileOutputStream.java:66)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at java.io.FileWriter.<init>(FileWriter.java:42)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at org.zelos.asm.main.writeFile(main.java:30)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at org.zelos.asm.main.onCreate(main.java:19)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at android.os.Handler.dispatchMessage(Handler.java:99)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at android.os.Looper.loop(Looper.java:123)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at android.app.ActivityThread.main(ActivityThread.java:3683)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at java.lang.reflect.Method.invokeNative(Native Method)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at java.lang.reflect.Method.invoke(Method.java:507)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
02-27 10:03:56.162: DEBUG/StrictMode(16210): at dalvik.system.NativeStart.main(Native Method)
