Cocos2d-x 添加安卓按鍵監聽事件

在遊戲開發中，需要對安卓平臺的菜單鍵和返回鍵的點擊做處理，如下：

3.x 版本

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

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

        case EventKeyboard::KeyCode::KEY_MENU:
            //菜單鍵
            break;

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

2.x版本

調用下面的接口

setKeypadEnabled(true);

然後重寫下面的兩個接口

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