Android 1.6: "android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application"

Question

I'm trying to open a dialog window, but every time I try to open it it throws this exception:

E/AndroidRuntime(  206): Uncaught handler: thread main exiting due to uncaught exception
E/AndroidRuntime(  206): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
E/AndroidRuntime(  206):    at android.view.ViewRoot.setView(ViewRoot.java:460)
E/AndroidRuntime(  206):    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
E/AndroidRuntime(  206):    at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
E/AndroidRuntime(  206):    at android.app.Dialog.show(Dialog.java:238)
E/AndroidRuntime(  206):    at android.app.Activity.showDialog(Activity.java:2413)

I'm creating it by calling showDialog with the display's id. The onCreateDialog handler logs fine and I can step through it without an issue, but I've attached it since it seems like I'm missing something:

@Override
public Dialog onCreateDialog(int id)
{
    Dialog dialog;
    Context appContext = this.getApplicationContext();
    switch(id)
    {
        case RENAME_DIALOG_ID:
            Log.i("Edit", "Creating rename dialog...");
            dialog = new Dialog(appContext);
            dialog.setContentView(R.layout.rename);
            dialog.setTitle("Rename " + noteName);
            break;
        default:
            dialog = null;
            break;
    }
    return dialog;      
}

Is there something missing from this? Some questions have talked about having this problem when creating a dialog from onCreate, which happen because the activity isn't created yet, but this is coming from a call from a menu object, and the appContext variable seems like it is correctly populated in the debugger.

Answer 1

You cannot display an application window/dialog through a Context that is not an Activity. Try passing a valid activity reference

Answer 2

i.e. this line: Context appContext = this.getApplicationContext(); must go, and instead you use a pointer to the activity you're in (probably this).

I got bitten by this today too, the annoying part is the getApplicationContext() is verbatim from developer.android.com :(

Answer 3

ditto on the getApplicationContext thing.

The docs on the android site says to use it, but it doesn't work...grrrrr :-P

Just do: dialog = new Dialog(this); "this" is usually your Activity from which you start the dialog.