BadTokenException: Unable to add window

Question

I have an issue where I receive a BadTokenException when the screen times out, and then the user returns to my application. I have a button which opens up a ContextMenu when clicked.

It works fine normally, but when the user lets the screen time out, and then returns to the application, a BadTokenException is thrown.

07-01 14:46:42.763: WARN/WindowManager(1105): Attempted to add window with token that is a sub-window: android.os.BinderProxy@44af17c8.  Aborting.
    07-01 14:46:42.771: WARN/System.err(1725):     at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:459)
    07-01 14:46:42.771: WARN/System.err(1725):     at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:459)
    07-01 14:46:42.771: WARN/System.err(1725):     at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:459)
    07-01 14:46:42.771: WARN/System.err(1725):     at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:459)
    07-01 14:46:42.771: WARN/System.err(1725):     at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:459)
    07-01 14:46:42.771: WARN/System.err(1725):     at android.view.View.showContextMenu(View.java:2444)
    07-01 14:46:42.771: WARN/System.err(1725):     at com.??.??.ui.cards.ViewActivity$3.onClick(ViewActivity.java:353)
    07-01 14:46:42.771: WARN/System.err(1725):     at android.view.View.performClick(View.java:2408)
    07-01 14:46:42.771: WARN/System.err(1725):     at android.view.View$PerformClick.run(View.java:8816)
    07-01 14:46:42.771: WARN/System.err(1725):     at android.os.Handler.handleCallback(Handler.java:587)
    07-01 14:46:42.771: WARN/System.err(1725):     at android.os.Handler.dispatchMessage(Handler.java:92)
    07-01 14:46:42.771: WARN/System.err(1725):     at android.os.Looper.loop(Looper.java:123)
    07-01 14:46:42.771: WARN/System.err(1725):     at android.app.ActivityThread.main(ActivityThread.java:4627)
    07-01 14:46:42.771: WARN/System.err(1725):     at java.lang.reflect.Method.invokeNative(Native Method)
    07-01 14:46:42.771: WARN/System.err(1725):     at java.lang.reflect.Method.invoke(Method.java:521)
    07-01 14:46:42.771: WARN/System.err(1725):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
    07-01 14:46:42.771: WARN/System.err(1725):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
    07-01 14:46:42.771: WARN/System.err(1725):     at dalvik.system.NativeStart.main(Native Method)
    07-01 14:46:43.005: WARN/System.err(1725): android.view.WindowManager$BadTokenException: Unable to add window -- token android.view.ViewRoot$W@44757528 is not valid; is your activity running?
    07-01 14:46:43.005: WARN/System.err(1725):     at android.view.ViewRoot.setView(ViewRoot.java:505)
    07-01 14:46:43.005: WARN/System.err(1725):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
    07-01 14:46:43.005: WARN/System.err(1725):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
    07-01 14:46:43.005: WARN/System.err(1725):     at android.view.Window$LocalWindowManager.addView(Window.java:424)
    07-01 14:46:43.005: WARN/System.err(1725):     at android.app.Dialog.show(Dialog.java:241)
    07-01 14:46:43.005: WARN/System.err(1725):     at com.android.internal.view.menu.MenuDialogHelper.show(MenuDialogHelper.java:86)
    07-01 14:46:43.005: WARN/System.err(1725):     at com.android.internal.view.menu.ContextMenuBuilder.show(ContextMenuBuilder.java:88)
    07-01 14:46:43.005: WARN/System.err(1725):     at com.android.internal.policy.impl.PhoneWindow$DecorView.showContextMenuForChild(PhoneWindow.java:1860)
    07-01 14:46:43.005: WARN/System.err(1725):     at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:459)
    07-01 14:46:43.005: WARN/System.err(1725):     at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:459)
    07-01 14:46:43.005: WARN/System.err(1725):     at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:459)
    07-01 14:46:43.005: WARN/System.err(1725):     at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:459)
    07-01 14:46:43.005: WARN/System.err(1725):     at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:459)
    07-01 14:46:43.005: WARN/System.err(1725):     at android.view.ViewGroup.showContextMenuForChild(ViewGroup.java:459)

If I catch the Exception, the button never opens up the contextmenu in this case, but other controls on the page continue to work.

If I minimize the application with the home screen, and then return, the application crashes with the following trace:

07-01 15:10:50.439: ERROR/AndroidRuntime(1931): FATAL EXCEPTION: main
07-01 15:10:50.439: ERROR/AndroidRuntime(1931): java.lang.NullPointerException
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at android.view.WindowManagerImpl.removeViewLocked(WindowManagerImpl.java:239)
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at android.view.WindowManagerImpl.closeAll(WindowManagerImpl.java:293)
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3687)
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at android.app.ActivityThread.access$2900(ActivityThread.java:125)
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at android.os.Looper.loop(Looper.java:123)
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at android.app.ActivityThread.main(ActivityThread.java:4627)
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at java.lang.reflect.Method.invokeNative(Native Method)
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at java.lang.reflect.Method.invoke(Method.java:521)
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
07-01 15:10:50.439: ERROR/AndroidRuntime(1931):     at dalvik.system.NativeStart.main(Native Method)

Here's how I'm adding the ContextMenu:

b.setOnClickListener( new OnClickListener() {
            @Override
            public void onClick( View view ) {
                if (contextMenuOpen) return;// popup options
                contextMenuOpen = view.showContextMenu();

            }

I do not call registerForContextMenu with the button, but rather the main view itself. Is this incorrect?

Answer 1

You are holding on to a reference to a Context (either explicitly, or by creating a Dialog or Toast or some other dependent item) that has been destroyed (typically because you are using the onCreateDialog or you passed the Activity to some other process that didn't get destroyed when the Activity was destroyed).