[android] Unable to add window -- token android.os.BinderProxy is not valid; is your activity running?

Another developer use case: If the WindowManager or getWindow() is being called on onCreate() or onStart() or onResume(), a BadTokenException is thrown. You will need to wait until the view is prepared and attached.

Moving the code to onAttachedToWindow() solves it. It may not be a permanent solution, but as much as I could test, it always worked.

In my case, there was a need to increase the screen brightness when the activity became visible. The line getWindow().getAttributes().screenBrightness in the onResume() resulted in an exception. Moving the code to onAttachedToWindow() worked.