我一直在尝试使用Android打开辅助功能服务。我使用Android Studio（Nexus S API 19，armabi-v7）运行模拟器。我可以在模拟器运行时打开辅助功能设置。 （点击带圆圈的子菜单） Setting Screen with Accessibility Sub-Menu highlighted
然而，当我跑步时，尝试通过打开一个交互式的monkeyrunner终端并运行来附加monkeyrunner：
>> from android.com.monkeyrunner import MonkeyRunner, MonkeyDevice
>> d = MonkeyRunner.waitForConnection()
我无法导航到辅助功能设置屏幕并收到错误消息
Result of selecting accessibility sub-menu from settings when MonkeyDevice is attached
一旦我分离了MonkeyDevice，我就可以再次进入辅助功能设置屏幕。知道是什么原因引起的吗？
如果出现错误，请从日志中获取代码段
##Logs from Failure ## I/ActivityManager( 357): START u0 {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.android.settings/.Settings} from pid 519 ... I/ActivityManager( 357): START u0 {act=android.intent.action.MAIN cmp=com.android.settings/.SubSettings (has extras)} from pid 751
...
D/SubSettings( 751): Launching fragment com.android.settings.accessibility.AccessibilitySettings ... E/AndroidRuntime( 751): FATAL EXCEPTION: main
E/AndroidRuntime( 751): Process: com.android.settings, PID: 751
E/AndroidRuntime( 751): java.lang.RuntimeException: Unable to resume activity {com.android.settings/com.android.settings.SubSettings}: java.lang.NullPointerException
E/AndroidRuntime( 751): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2774)
E/AndroidRuntime( 751): at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2803)
E/AndroidRuntime( 751): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2238)
E/AndroidRuntime( 751): at android.app.ActivityThread.access$800(ActivityThread.java:135)
E/AndroidRuntime( 751): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
E/AndroidRuntime( 751): at android.os.Handler.dispatchMessage(Handler.java:102)
E/AndroidRuntime( 751): at android.os.Looper.loop(Looper.java:136)
E/AndroidRuntime( 751): at android.app.ActivityThread.main(ActivityThread.java:5001)
E/AndroidRuntime( 751): at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime( 751): at java.lang.reflect.Method.invoke(Method.java:515)
E/AndroidRuntime( 751): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
E/AndroidRuntime( 751): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
E/AndroidRuntime( 751): at dalvik.system.NativeStart.main(Native Method)
E/AndroidRuntime( 751): Caused by: java.lang.NullPointerException
E/AndroidRuntime( 751): at com.android.settings.accessibility.AccessibilitySettings.loadInstalledServices(AccessibilitySettings.java:641)
E/AndroidRuntime( 751): at com.android.settings.accessibility.AccessibilitySettings.onResume(AccessibilitySettings.java:214)
E/AndroidRuntime( 751): at android.app.Fragment.performResume(Fragment.java:1743)
E/AndroidRuntime( 751): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:924)
E/AndroidRuntime( 751): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062)
E/AndroidRuntime( 751): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1044)
E/AndroidRuntime( 751): at android.app.FragmentManagerImpl.dispatchResume(FragmentManager.java:1863)
E/AndroidRuntime( 751): at android.app.Activity.performResume(Activity.java:5320)
E/AndroidRuntime( 751): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2764)
E/AndroidRuntime( 751): ... 12 more
W/ActivityManager( 357): Force finishing activity com.android.settings/.SubSettings
W/ActivityManager( 357): Force finishing activity com.android.settings/.Settings ... W/ActivityManager( 357): Activity pause timeout for ActivityRecord{b3ea9e08 u0 com.android.settings/.SubSettings t2 f}
似乎有一个NullPointer异常，但我不知道是什么原因造成的
##Log Snippet Without Failure I/ActivityManager( 357): START u0 {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.android.settings/.Settings} from pid 519
I/ActivityManager( 357): Start proc com.android.settings for activity com.android.settings/.Settings: pid=1095 uid=1000 gids={41000, 1028, 1015, 3002, 3001, 3003}
D/dalvikvm( 59): GC_EXPLICIT freed 40K, 5% free 2777K/2900K, paused 15ms+3ms, total 96ms
D/dalvikvm( 59): GC_EXPLICIT freed <1K, 5% free 2777K/2900K, paused 3ms+14ms, total 67ms
D/dalvikvm( 59): GC_EXPLICIT freed <1K, 5% free 2777K/2900K, paused 7ms+14ms, total 76ms
D/dalvikvm( 1095): GC_FOR_ALLOC freed 118K, 7% free 2987K/3188K, paused 35ms, total 37ms
I/dalvikvm-heap( 1095): Grow heap (frag case) to 3.602MB for 635812-byte allocation
D/dalvikvm( 1095): GC_FOR_ALLOC freed 3K, 6% free 3605K/3812K, paused 44ms, total 44ms
D/dalvikvm( 1095): GC_CONCURRENT freed <1K, 6% free 3605K/3812K, paused 4ms+2ms, total 53ms
E/BluetoothAdapter( 1095): Bluetooth binder is null
D/dalvikvm( 1095): GC_CONCURRENT freed 209K, 8% free 3793K/4088K, paused 2ms+16ms, total 65ms
D/ ( 1095): HostConnection::get() New Host Connection established 0xb82ef4c0, tid 1095
W/EGL_emulation( 1095): eglSurfaceAttrib not implemented
D/OpenGLRenderer( 1095): Enabling debug mode 0
I/ActivityManager( 357): Displayed com.android.settings/.Settings:
+2s599ms
D/dalvikvm( 1095): GC_CONCURRENT freed 124K, 5% free 4057K/4268K, paused 15ms+5ms, total 101ms
I/ActivityManager( 357): START u0 {act=android.intent.action.MAIN cmp=com.android.settings/.SubSettings (has extras)} from pid 1095
D/SubSettings( 1095): Launching fragment com.android.settings.accessibility.AccessibilitySettings
W/EGL_emulation( 1095): eglSurfaceAttrib not implemented
D/dalvikvm( 1095): GC_CONCURRENT freed 223K, 7% free 4267K/4576K, paused 20ms+65ms, total 345ms
I/Choreographer( 1095): Skipped 120 frames! The application may be doing too much work on its main thread.
I/ActivityManager( 357): Displayed com.android.settings/.SubSettings:
+3s235ms