The methods:
- waitForVerifierCode()
- waitForExplicitCode()
- waitForImplicitResponseUrl()
in DialogFragmentController will all throw a CancellationException if a user presses back when the authorization dialog is open, which is prone to happen. I suggest removing it or making it throw another exception. The fastest way is to just throw another IOException, which is already present in the code, and let users either ignore it or take action upon it.