我正在自定义 ListView 并在其行中使用 Spinner。虽然列表显示正确，但是当我单击 Spinner 时会引发异常。
08-22 17:11:08.705: E/AndroidRuntime(1168): FATAL EXCEPTION: main
08-22 17:11:08.705: E/AndroidRuntime(1168): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
08-22 17:11:08.705: E/AndroidRuntime(1168): at android.view.ViewRoot.setView(ViewRoot.java:531)
08-22 17:11:08.705: E/AndroidRuntime(1168): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
08-22 17:11:08.705: E/AndroidRuntime(1168): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
08-22 17:11:08.705: E/AndroidRuntime(1168): at android.app.Dialog.show(Dialog.java:241)
08-22 17:11:08.705: E/AndroidRuntime(1168): at android.app.AlertDialog$Builder.show(AlertDialog.java:802)
08-22 17:11:08.705: E/AndroidRuntime(1168): at android.widget.Spinner.performClick(Spinner.java:260)
08-22 17:11:08.705: E/AndroidRuntime(1168): at android.view.View$PerformClick.run(View.java:9080)
08-22 17:11:08.705: E/AndroidRuntime(1168): at android.os.Handler.handleCallback(Handler.java:587)
08-22 17:11:08.705: E/AndroidRuntime(1168): at android.os.Handler.dispatchMessage(Handler.java:92)
08-22 17:11:08.705: E/AndroidRuntime(1168): at android.os.Looper.loop(Looper.java:130)
08-22 17:11:08.705: E/AndroidRuntime(1168): at android.app.ActivityThread.main(ActivityThread.java:3683)
08-22 17:11:08.705: E/AndroidRuntime(1168): at java.lang.reflect.Method.invokeNative(Native Method)
08-22 17:11:08.705: E/AndroidRuntime(1168): at java.lang.reflect.Method.invoke(Method.java:507)
08-22 17:11:08.705: E/AndroidRuntime(1168): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
08-22 17:11:08.705: E/AndroidRuntime(1168): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
08-22 17:11:08.705: E/AndroidRuntime(1168): at dalvik.system.NativeStart.main(Native Method)
请帮忙。