gistfile1.as

private function initHandlers():void {	
			NativeApplication.nativeApplication.addEventListener(KeyboardEvent.KEY_DOWN, checkKeypress);
			NativeApplication.nativeApplication.addEventListener(Event.DEACTIVATE, deactivateListener)	
		}

public function checkKeypress(event:KeyboardEvent):void  {
			switch (event.keyCode){
				case Keyboard.BACK:
					event.preventDefault();
					NativeApplication.nativeApplication.exit();	
					break;
				case Keyboard.MENU:
					trace("Menu key is pressed.");
					break;
				case Keyboard.SEARCH:
					trace("Search key is pressed.");
					break;
			}
		} 

protected function deactivateListener(event:Event):void  {
			// закрываем, если андроид, а не эмулятор или делаем что-то ещё, например закрываем все загрузки и уходим в слип
			if (Capabilities.playerType.search("Linux") != -1)
				NativeApplication.nativeApplication.exit();			
		}