As related to the new guidelines I replaced my standard menu with the actionbar. Due to consistent design I want to use the actionbar for all devices where it is possible to use the action bar. But there are a lot of devices which support actionbar and still have a menu button. How to handle this devices? I think it feels wront in some way, if the user clicks on the menu button and nothing happens. I know, that I can catch the button click but what to do then? How to react on this click? Is there some method/usual way to point the user's attention to the actionbar?
If you have overflow menu items, then the menu button will open the overflow menu. If you don't, then yes, the menu button will do nothing. I don't think that this behaviour is strange to users - there are many apps without menus. Otherwise, I suppose you could have your action bar or your menu items flash a different colour briefly. But this is by no means standard.