“Window Manager Crash” on dispatching 'Down' key on Samsung Galaxy S-Collection of common programming errors

I am running my Unit tests on various android devices using Instrumentation . Testcases works fine on emulator & all devices except Samsung Galaxy S. On Samsung Galaxy S it displays a Window Manager crash after injecting some 30 key events using instrumentation here is the complete crash log:

D/dalvikvm(11862): GC_EXPLICIT freed 6800 objects / 374040 bytes in 54ms
D/dalvikvm(11862): GC_EXPLICIT freed 780 objects / 71856 bytes in 39ms
W/dalvikvm(11862): threadid=9: thread exiting with uncaught exception (group=0x4001d7d0)
E/WindowManager( 2472): Window Manager Crash
E/WindowManager( 2472): java.lang.NullPointerException
E/WindowManager( 2472):         at com.android.server.WindowManagerService$KeyWaiter.waitForNextEventTarget(WindowManagerService.java:5844)
E/WindowManager( 2472):         at com.android.server.WindowManagerService.injectKeyEvent(WindowManagerService.java:5565)
E/WindowManager( 2472):         at android.view.IWindowManager$Stub.onTransact(IWindowManager.java:110)
E/WindowManager( 2472):         at com.android.server.WindowManagerService.onTransact(WindowManagerService.java:692)
E/WindowManager( 2472):         at android.os.Binder.execTransact(Binder.java:288)
E/WindowManager( 2472):         at dalvik.system.NativeStart.run(Native Method)
E/AndroidRuntime(11862): FATAL EXCEPTION: Instr: com.myapp.test.ImpInstrumentation
E/AndroidRuntime(11862): java.lang.NullPointerException
E/AndroidRuntime(11862):        at android.os.Parcel.readException(Parcel.java:1266)
E/AndroidRuntime(11862):        at android.os.Parcel.readException(Parcel.java:1248)
E/AndroidRuntime(11862):        at android.view.IWindowManager$Stub$Proxy.injectKeyEvent(IWindowManager.java:830)
E/AndroidRuntime(11862):        at android.app.Instrumentation.sendKeySync(Instrumentation.java:859)
E/AndroidRuntime(11862):        at android.app.Instrumentation.sendKeyDownUpSync(Instrumentation.java:872)
E/AndroidRuntime(11862):        at com.myapp.test.util.ListUtil.arrowDownToPosition(ListUtil.java:69)

And here is the piece of code where it generally crashes:

    private void arrowDownToPosition(int position) {
          int maxDowns = 50;
        while(mListView.getSelectedItemPosition() < position && --maxDowns > 0) {
             mInstrumentation.sendKeyDownUpSync(KeyEvent.KEYCODE_DPAD_DOWN);
        }

//Crashes on below line dispatching enter key
      mInstrumentation.sendKeyDownUpSync(KeyEvent.KEYCODE_ENTER);
    }

All solutions/suggestions are welcome.

1. Not sure if this helps, but while briefly researching this issue, I found this source. Have a look, particularly from line 175 about a bug with DPAD_CENTER on the Galaxy S, and how the issue is resolved.

2. according to your stacktrace it seems that your variable mInstrumentation is null. did you forget to initialize it?

   try this:

   while(mInstrumentation!=null && mListView.getSelectedItemPosition()>-1) {
       mInstrumentation.sendKeyDownUpSync(KeyEvent.KEYCODE_DPAD_DOWN);
   }