android - 发生 ANR 时选择确定以重新启动启动器时丢弃事件

Question

当 Launcher 发生 ANR 时，弹出对话框，然后 Launcher 恢复。启动器恢复响应后，选择确定重启启动器，其余键将被丢弃。

问题出现在我的开发环境中，很难复现，所以我做了一个测试:

1. 创建一个简单的 APK 作为启动器，并在 onCreat 或 onResume 中休眠一段时间以让 ANR 发生
2. 启动 Launcher 并按下 键让 ANR 发生
3. sleep 后 View 通常显示在 ANR 对话框后面选择确定以重新启动启动器，然后无法接收 key ，因为无法创建 Activity
4. 因为没有焦点窗口或焦点应用程序而丢弃事件

该APK用于Android4.0和Android2.2Android2.2没问题，Android 4.03好像有问题。2.2、4.03的真测问题和仿真问题都补充了日志。另外:我也修改了原来的Launcher2并且在onResume中休眠，它没有这个问题但我找不到任何线索。

感谢任何帮助。

---

Android4.0

09-10 17:29:44.716 W/ActivityManager(   77):   Force finishing activity       com.example.testanr2/.MainActivity
09-10 17:29:44.716 W/WindowManager(   77): Failure taking screenshot for (180x300) to layer 21005
09-10 17:29:44.736 I/ActivityManager(   77): Clearing package preferred activities from com.example.testanr2
09-10 17:29:44.736 I/ActivityManager(   77): Killing ProcessRecord{415df8d8 2409:com.example.testanr2/10040}: user's request
09-10 17:29:44.756 I/WindowManager(   77): WIN DEATH: Window{41444c48 com.example.testanr2/com.example.testanr2.MainActivity paused=true}
09-10 17:29:44.765 I/ActivityManager(   77): START {act=android.intent.action.MAIN cat=[android.intent.category.HOME] flg=0x10000000 cmp=com.example.testanr2/.MainActivity} from pid 0
09-10 17:29:44.786 W/ActivityManager(   77): Exception when starting activity com.example.testanr2/.MainActivity
09-10 17:29:44.786 W/ActivityManager(   77): android.os.DeadObjectException
09-10 17:29:44.786 W/ActivityManager(   77):    at android.os.BinderProxy.transact(Native Method)
09-10 17:29:44.786 W/ActivityManager(   77):    at android.app.ApplicationThreadProxy.scheduleLaunchActivity(ApplicationThreadNative.java:660)
09-10 17:29:44.786 W/ActivityManager(   77):    at com.android.server.am.ActivityStack.realStartActivityLocked(ActivityStack.java:593)
09-10 17:29:44.786 W/ActivityManager(   77):    at com.android.server.am.ActivityStack.startSpecificActivityLocked(ActivityStack.java:701)
09-10 17:29:44.786 W/ActivityManager(   77):    at com.android.server.am.ActivityStack.resumeTopActivityLocked(ActivityStack.java:1571)
09-10 17:29:44.786 W/ActivityManager(   77):    at com.android.server.am.ActivityStack.completePauseLocked(ActivityStack.java:1000)
09-10 17:29:44.786 W/ActivityManager(   77):    at com.android.server.am.ActivityStack.activityPaused(ActivityStack.java:928)
09-10 17:29:44.786 W/ActivityManager(   77):    at com.android.server.am.ActivityManagerService.activityPaused(ActivityManagerService.java:3957)
09-10 17:29:44.786 W/ActivityManager(   77):    at android.app.ActivityManagerNative.onTransact(ActivityManagerNative.java:371)
09-10 17:29:44.786 W/ActivityManager(   77):    at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:1496)
09-10 17:29:44.786 W/ActivityManager(   77):    at android.os.Binder.execTransact(Binder.java:338)
09-10 17:29:44.786 W/ActivityManager(   77):    at dalvik.system.NativeStart.run(Native Method)
09-10 17:29:44.786 W/ActivityManager(   77): Force removing ActivityRecord{414b0020 com.example.testanr2/.MainActivity}: app died, no saved state
09-10 17:29:44.836 D/dalvikvm( 2438): Not late-enabling CheckJNI (already on)
09-10 17:29:44.855 I/ActivityManager(   77): Start proc com.example.testanr2 for activity com.example.testanr2/.MainActivity: pid=2438 uid=10040 gids={}
09-10 17:29:44.855 I/ActivityManager(   77): Process com.example.testanr2 (pid 2409) has died and restarted (pid 2438).
09-10 17:29:44.855 W/NetworkManagementSocketTagger(   77): setKernelCountSet(10040, 0) failed with errno -2
09-10 17:29:47.562 I/InputDispatcher(   77): Dropping event because there is no touched window or focused application.
09-10 17:29:47.828 I/InputDispatcher(   77): Dropping event because there is no touched window or focused application.
09-10 17:29:47.965 D/dalvikvm(  161): GC_CONCURRENT freed 384K, 6% free 10331K/10951K, paused 7ms+3ms
09-10 17:29:48.135 I/InputDispatcher(   77): Dropping event because there is no touched window or focused application.
09-10 17:29:50.207 I/InputDispatcher(   77): Dropping event because there is no touched window or focused application.
09-10 17:29:50.708 I/InputDispatcher(   77): Dropping event because there is no touched window or focused application.
09-10 17:29:50.991 I/InputDispatcher(   77): Dropping event because there is no touched window or focused application.
09-10 17:29:51.205 I/InputDispatcher(   77): Dropping event because there is no touched window or focused application.
09-10 17:29:51.362 I/InputDispatcher(   77): Dropping event because there is no touched window or focused application.
09-10 17:29:54.746 W/ActivityManager(   77): Launch timeout has expired, giving up wake lock!
09-10 17:29:57.877 I/InputDispatcher(   77): Dropping event because there is no touched window or focused application.

Android2.2

09-10 16:40:32.254 D/PackageManager(   72): New package installed in /data/app/com.example.testanr2-1.apk
09-10 16:40:32.304 D/lixin   (  668): sleep~ in application10
09-10 16:40:32.394 I/ActivityManager(   72): Force stopping package com.example.testanr2 uid=10040
09-10 16:40:32.394 I/Process (   72): Sending signal. PID: 668 SIG: 9
09-10 16:40:32.414 I/ActivityManager(   72): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.HOME] flg=0x10000000 cmp=com.example.testanr2/.MainActivity }
09-10 16:40:32.484 D/dalvikvm(   72): GC_FOR_MALLOC freed 11945 objects / 732440 bytes in 67ms
09-10 16:40:32.484 I/ActivityManager(   72): Start proc com.example.testanr2 for activity com.example.testanr2/.MainActivity: pid=674 uid=10040 gids={}
09-10 16:40:32.604 D/dalvikvm(  198): GC_EXPLICIT freed 2644 objects / 128328 bytes in 105ms
09-10 16:40:32.734 D/dalvikvm(   72): GC_EXPLICIT freed 939 objects / 49752 bytes in 229ms
09-10 16:40:32.734 I/UsageStats(   72): Unexpected resume of com.example.testanr2 while already resumed in com.example.testanr2
09-10 16:40:32.834 W/RecognitionManagerService(   72): no available voice recognition services found
09-10 16:40:32.864 D/lixin   (  674): sleep~ in application10
09-10 16:40:32.915 D/dalvikvm(   72): GC_EXPLICIT freed 2356 objects / 116024 bytes in 77ms
09-10 16:40:32.954 I/installd(   34): unlink /data/dalvik-cache/data@app@com.example.testanr2-2.apk@classes.dex
09-10 16:40:32.984 D/AndroidRuntime(  654): Shutting down VM
09-10 16:40:32.984 D/dalvikvm(  654): Debugger has detached; object registry had 1 entries
09-10 16:40:33.245 D/AndroidRuntime(  684): 
09-10 16:40:33.245 D/AndroidRuntime(  684): >>>>>>>>>>>>>> AndroidRuntime START <<<<<<<<<<<<<<
09-10 16:40:33.245 D/AndroidRuntime(  684): CheckJNI is ON
09-10 16:40:33.334 D/AndroidRuntime(  684): --- registering native functions ---
09-10 16:40:33.665 I/ActivityManager(   72): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.example.testanr2/.MainActivity }
09-10 16:40:33.665 D/AndroidRuntime(  684): Shutting down VM
09-10 16:40:33.665 D/dalvikvm(  684): Debugger has detached; object registry had 1 entries
09-10 16:40:33.674 I/AndroidRuntime(  684): NOTE: attach of thread 'Binder Thread #3' failed
09-10 16:40:34.169 W/ActivityManager(   72): Activity pause timeout for HistoryRecord{45060dd8 com.example.testanr2/.MainActivity}
09-10 16:40:40.057 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:40.074 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:40.275 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:40.314 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:40.445 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:40.484 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:40.528 W/ActivityManager(   72): Launch timeout has expired, giving up wake lock!
09-10 16:40:40.678 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:40.714 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:40.864 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:40.874 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:41.604 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:41.637 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:41.755 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:41.786 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:41.936 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:41.954 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:42.088 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:42.124 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:42.234 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:42.295 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:42.404 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:42.444 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:42.595 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:42.614 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:42.744 W/ActivityManager(   72): Activity idle timeout for HistoryRecord{45060dd8 com.example.testanr2/.MainActivity}
09-10 16:40:42.744 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:42.754 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:42.885 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:42.885 D/lixin   (  674): sleep~ in application10
09-10 16:40:42.926 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:44.181 W/ActivityManager(   72): Activity idle timeout for        HistoryRecord{451b0480 com.example.testanr2/.MainActivity}
09-10 16:40:47.029 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:47.045 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:47.280 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:47.345 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:47.545 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:47.595 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:47.794 W/WindowManager(   72): No window to dispatch pointer action 0
09-10 16:40:47.865 W/WindowManager(   72): No window to dispatch pointer action 1
09-10 16:40:49.235 D/dalvikvm(  289): GC_EXPLICIT freed 353 objects / 19600 bytes in 56ms
09-10 16:40:52.924 W/InputManagerService(   72): Got RemoteException sending setActive(false) notification to pid 575 uid 10040
09-10 16:40:52.964 I/ActivityManager(   72): Displayed activity com.example.testanr2/.MainActivity: 18800 ms (total 22687 ms)

启动器 2

01-01 08:12:56.140 I/WindowManager( 1259): Handle special keys: 23 
01-01 08:12:56.145 W/ActivityManager( 1259):   Force finishing activity com.android.launcher/com.android.launcher2.Launcher
01-01 08:12:56.239 D/dalvikvm( 1259): GC_FOR_ALLOC freed 462K, 13% free 10871K/12423K, paused 48ms
01-01 08:12:56.242 D/UsageStats( 1259): UsageStats: broadcasting intent
01-01 08:12:56.244 I/ActivityManager( 1259): Clearing package preferred activities from com.android.launcher
01-01 08:12:56.244 I/ActivityManager( 1259): Killing ProcessRecord{40c2f498 2970:com.android.launcher/10032}: user's request
01-01 08:12:56.252 I/ActivityManager( 1259): START {act=android.intent.action.MAIN cat=[android.intent.category.HOME] flg=0x10000000 cmp=com.android.launcher/com.android.launcher2.Launcher} from pid 0
01-01 08:12:56.303 E/JavaBinder( 1259): !!! FAILED BINDER TRANSACTION !!!
01-01 08:12:56.330 W/ActivityManager( 1259): Exception when starting activity com.android.launcher/com.android.launcher2.Launcher
01-01 08:12:56.330 W/ActivityManager( 1259): android.os.TransactionTooLargeException
01-01 08:12:56.330 W/ActivityManager( 1259):    at android.os.BinderProxy.transact(Native Method)
01-01 08:12:56.330 W/ActivityManager( 1259):    at android.app.ApplicationThreadProxy.scheduleLaunchActivity(ApplicationThreadNative.java:660)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.am.ActivityStack.realStartActivityLocked(ActivityStack.java:615)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.am.ActivityStack.startSpecificActivityLocked(ActivityStack.java:724)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.am.ActivityStack.resumeTopActivityLocked(ActivityStack.java:1614)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.am.ActivityStack.startActivityLocked(ActivityStack.java:1760)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.am.ActivityStack.startActivityUncheckedLocked(ActivityStack.java:2802)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.am.ActivityStack.startActivityLocked(ActivityStack.java:2422)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.am.ActivityManagerService.startHomeActivityLocked(ActivityManagerService.java:2063)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.am.ActivityStack.resumeTopActivityLocked(ActivityStack.java:1299)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.am.ActivityStack.completePauseLocked(ActivityStack.java:1040)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.am.ActivityStack.activityPaused(ActivityStack.java:952)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.am.ActivityManagerService.activityPaused(ActivityManagerService.java:4140)
01-01 08:12:56.330 W/ActivityManager( 1259):    at android.app.ActivityManagerNative.onTransact(ActivityManagerNative.java:371)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:1548)
01-01 08:12:56.330 W/ActivityManager( 1259):    at android.os.Binder.execTransact(Binder.java:338)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.SystemServer.init1(Native Method)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.server.SystemServer.main(SystemServer.java:860)
01-01 08:12:56.330 W/ActivityManager( 1259):    at java.lang.reflect.Method.invokeNative(Native Method)
01-01 08:12:56.330 W/ActivityManager( 1259):    at java.lang.reflect.Method.invoke(Method.java:511)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
01-01 08:12:56.330 W/ActivityManager( 1259):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
01-01 08:12:56.330 W/ActivityManager( 1259):    at dalvik.system.NativeStart.main(Native Method)
01-01 08:12:56.345 E/JavaBinder( 1259): !!! FAILED BINDER TRANSACTION !!!
01-01 08:12:56.408 I/ActivityManager( 1259): Start proc com.android.launcher for activity com.android.launcher/com.android.launcher2.Launcher: pid=3000 uid=10032 gids={}
01-01 08:12:56.484 D/UsageStats( 1259): UsageStats: broadcasting intent
01-01 08:12:56.613 I/ActivityThread( 3000): Pub com.android.launcher2.settings: com.android.launcher2.LauncherProvider
01-01 08:12:56.862 D/dalvikvm( 3000): GC_FOR_ALLOC freed 164K, 5% free 7837K/8199K, paused 21ms
01-01 08:12:56.986 I/Process ( 1259): Sending signal. PID: 3000 SIG: 3
01-01 08:12:56.986 I/dalvikvm( 3000): threadid=3: reacting to signal 3
01-01 08:12:57.007 W/WindowManager( 1259): Rebuild removed 2 windows but added 1
01-01 08:12:57.012 W/WindowManager( 1259): This window was lost: Window{40c51350 com.android.launcher/com.android.launcher2.Launcher paused=true}
01-01 08:12:57.012 W/WindowManager( 1259): mSession=Session{40bee818 uid 10032} mClient=android.os.BinderProxy@40bbecd8
01-01 08:12:57.012 W/WindowManager( 1259): mAttrs=WM.LayoutParams{(0,0)(fillxfill) sim=#20 ty=1 fl=#1810100 pfl=0x8 fmt=-2 wanim=0x1030292}
01-01 08:12:57.012 W/WindowManager( 1259): Requested w=1920 h=1080 mLayoutSeq=148
01-01 08:12:57.012 W/WindowManager( 1259): mBaseLayer=21000 mSubLayer=0 mAnimLayer=21000+0=21000 mLastLayer=21000
01-01 08:12:57.012 W/WindowManager( 1259): mSurface=Surface(name=com.android.launcher/com.android.launcher2.Launcher, identity=34)
01-01 08:12:57.012 W/WindowManager( 1259): Surface: shown=false layer=21000 alpha=1.0 rect=(0.0,0.0) 1920.0 x 1080.0
01-01 08:12:57.012 W/WindowManager( 1259): mToken=AppWindowToken{40cb7750 token=Token{40b37598 ActivityRecord{40b9c4c0 com.android.launcher/com.android.launcher2.Launcher}}}
01-01 08:12:57.012 W/WindowManager( 1259): mRootToken=AppWindowToken{40cb7750 token=Token{40b37598 ActivityRecord{40b9c4c0 com.android.launcher/com.android.launcher2.Launcher}}}
01-01 08:12:57.012 W/WindowManager( 1259): mAppToken=AppWindowToken{40cb7750 token=Token{40b37598 ActivityRecord{40b9c4c0 com.android.launcher/com.android.launcher2.Launcher}}}
01-01 08:12:57.012 W/WindowManager( 1259): mViewVisibility=0x0 mLastHidden=true mHaveFrame=true mObscured=false
01-01 08:12:57.012 W/WindowManager( 1259): mSeq=0 mSystemUiVisibility=0x0
01-01 08:12:57.012 W/WindowManager( 1259): mGivenContentInsets=[0,0][0,0] mGivenVisibleInsets=[0,0][0,0]
01-01 08:12:57.012 W/WindowManager( 1259): mConfiguration={1.0 0mcc0mnc zh_CN layoutdir=0 sw720dp w1280dp h720dp xlrg long land -touch -keyb/v/h dpad/v s.4}
01-01 08:12:57.012 W/WindowManager( 1259): mShownFrame=[0.0,0.0][1920.0,1080.0]
01-01 08:12:57.012 W/WindowManager( 1259): mFrame=[0,0][1920,1080] last=[0,0][1920,1080]
01-01 08:12:57.012 W/WindowManager( 1259): mContainingFrame=[0,0][1920,1080] mParentFrame=[0,0][1920,1080] mDisplayFrame=[0,0][1920,1080]
01-01 08:12:57.012 W/WindowManager( 1259): mContentFrame=[0,0][1920,1080] mVisibleFrame=[0,0][1920,1080]
01-01 08:12:57.012 W/WindowManager( 1259): mContentInsets=[0,0][0,0] last=[0,0][0,0] mVisibleInsets=[0,0][0,0] last=[0,0][0,0]
01-01 08:12:57.012 W/WindowManager( 1259): mDrawPending=false mCommitDrawPending=false mReadyToShow=false mHasDrawn=true
01-01 08:12:57.012 W/WindowManager( 1259): mWallpaperX=0.5 mWallpaperY=0.5
01-01 08:12:57.012 W/WindowManager( 1259): mWallpaperXStep=0.25 mWallpaperYStep=1.0
01-01 08:12:57.012 W/WindowManager( 1259): Current app token list:
01-01 08:12:57.012 V/WindowManager( 1259):   #0: Token{40ba4ee8 ActivityRecord{40bb8cd8 com.android.launcher/com.android.launcher2.Launcher}}
01-01 08:12:57.012 W/WindowManager( 1259): Final window list:
01-01 08:12:57.012 V/WindowManager( 1259):   #1: Window{40b78338 InputMethod paused=false}
01-01 08:12:57.012 V/WindowManager( 1259):   #0: Window{40c6f7b8 Starting com.android.launcher paused=false}
01-01 08:12:57.035 I/WindowManager( 1259): WIN DEATH: Window{40c51350 com.android.launcher/com.android.launcher2.Launcher paused=true}
01-01 08:12:57.039 I/dalvikvm( 3000): Wrote stack traces to '/data/anr/traces.txt'
01-01 08:12:57.051 D/dalvikvm( 3000): GC_CONCURRENT freed 264K, 6% free 8034K/8519K, paused 5ms+1ms
01-01 08:12:57.251 D/dalvikvm( 3000): GC_FOR_ALLOC freed 168K, 5% free 8217K/8583K, paused 14ms
01-01 08:12:57.263 I/dalvikvm-heap( 3000): Grow heap (frag case) to 10.641MB for 2560016-byte allocation
01-01 08:12:57.278 D/dalvikvm( 3000): GC_CONCURRENT freed 13K, 4% free 10704K/11143K, paused 2ms+1ms
01-01 08:12:57.358 D/dalvikvm( 3000): GC_FOR_ALLOC freed 0K, 4% free 10704K/11143K, paused 10ms
01-01 08:12:57.370 D/KeyLayoutMap( 1259): mapKey: scanCode=106 ~ Result keyCode=22, flags=0x00000002.
01-01 08:12:57.370 D/InputReader( 1259): receive key event: device=6 type=0x0001 scancode=106(0x006a) keycode=22(0x0016) value=0x00000001 flags=0x00000002
01-01 08:12:57.370 I/WindowManager( 1259): Handle special keys: 22 
01-01 08:12:57.372 I/dalvikvm-heap( 3000): Grow heap (frag case) to 12.001MB for 1440016-byte allocation
01-01 08:12:57.394 D/dalvikvm( 3000): GC_CONCURRENT freed 0K, 4% free 12110K/12551K, paused 1ms+2ms
01-01 08:12:57.453 D/Launcher( 3000): #### onCreate setBackgroundColor
01-01 08:12:57.454 D/Launcher( 3000): sleep~main10

Answer 1

我将属性添加到启动器 list 中的主要 Activity

android:clearTaskOnLaunch="true"  
android:stateNotNeeded="true"

这两个属性在Android中原来的Launcher里面可以解决这个问题但它为何起作用仍然未知。