AIR 27 - Alt+Enter toggles fullscreen; behavior not cancelable

[tconkling]

Problem Description

Beginning in AIR 27, holding Alt and pressing Enter (or Numpad-Enter) toggles a Windows app's fullscreen state. Installing a KEY_DOWN event listener and calling Event.preventDefault() doesn't prevent this behavior.

Tracker link: https://tracker.adobe.com/#/view/AIR-4198470

Steps to Reproduce

Build a Windows app with AIR 27. Hold Alt and press the Enter key.

The app will toggle its fullscreen state. This behavior cannot be canceled with Event.preventDefault:

stage.addEventListener(KeyboardEvent.KEY_DOWN, function (e :KeyboardEvent) :void {
   if ((e.keyCode == Keyboard.ENTER && e.altKey) ||
        (e.keyCode == Keyboard.NUMPAD_ENTER && e.altKey)) {
       // this has no effect
       e.preventDefault();
   }
}, true);

[itlancer]

Essential feature. Need a way to disable or override such behavior.
Alt+Enter could lead unexpectable behavior and application crashes:
#246
#247
One important notice.
Alt+Enter fullscreen will be "enabled" only with <renderMode>direct</renderMode> or <renderMode>gpu</renderMode> in application manifest.

[ajwfrost]

Just noticed this issue -> the Alt-Enter behaviour is coming from Direct3D 11, before we receive the key down message from Windows. So to disable this behaviour we have to turn it off completely. For people who might want this behaviour, I would suggest they handle the Alt-Enter keystroke per the above and then set the application into full-screen mode via the AIR APIs.

So .. just checking for anyone who's commented on this thread - would you be okay with us disabling the Alt-Enter behaviour at the DirectX layer? (Well, we'll be putting this change in, unless folk really want it to be handled via a separate mechanism such as in the app descriptor file...)

[itlancer]

@ajwfrost
"Default" Windows Alt+Enter behavior stopped working correctly for most of AIR applications about AIR version 23-26. So right now such behavior cause just problems. For backward compatibility and "old-school UX" I think AIR developers should handle Alt+Enter key events via AIR (please check that it could be handled) and make fullscreen switching logic manually using Stage:displayState and StageDisplayState.
If it will work - your suggested solution will be great.

[ajwfrost]

Just checked this, and it seems to work:

			stage.addEventListener(KeyboardEvent.KEY_DOWN, function (e :KeyboardEvent) :void {
				if ((e.keyCode == Keyboard.ENTER && e.altKey) ||
					(e.keyCode == Keyboard.NUMPAD_ENTER && e.altKey)) {
				   // this has no effect
				   e.preventDefault();
				   stage.displayState = StageDisplayState.FULL_SCREEN_INTERACTIVE;
				}
			}, true);

Note, there is still no impact of 'preventDefault' for a key event.. but hopefully it's no longer needed!

thanks

[itlancer]

@ajwfrost
Great! Hope to see it at new AIR release.

[itlancer]

Fixed with AIR 33.1.1.575+.
I think this issue should be closed.