Cocos2d-x 添加安卓按键监听事件

在游戏开发中，需要对安卓平台的菜单键和返回键的点击做处理，如下：

3.x 版本

auto keyboardListener = EventListenerKeyboard::create();
    keyboardListener->onKeyReleased = [](EventKeyboard::KeyCode keycode, Event* event){

        switch (keycode)
        {
        case EventKeyboard::KeyCode::KEY_ESCAPE:
            //返回键
            break;

        case EventKeyboard::KeyCode::KEY_MENU:
            //菜单键
            break;

        default:
            break;
        }
    };
    Director::getInstance()->getEventDispatcher()->addEventListenerWithSceneGraphPriority(keyboardListener, this);

2.x版本

调用下面的接口

setKeypadEnabled(true);

然后重写下面的两个接口

virtual void keyBackClicked();
virtual void keyMenuClicked();