cocos2d-x CC_SYNTHESIZE_READONLY

//定义一个只读属性Label，在类定义中可以使用this->getLabel来访问
    CC_SYNTHESIZE_READONLY(cocos2d::CCLabelTTF*,_label,Label);

CC_SYNTHESIZE_READONLY(varType, varName, funName)声明一个成员变量以及getfunName函数，没有set函数。getfunName已经实现，其实现就是返回这个值。

this ->_layer = GameOverLayer::node();
this ->_layer->retain();
this ->addChild(_layer);

bool GameOverLayer::init()
{
    if (CCLayerColor::initWithColor(ccc4(255,255,255,255)))
    {
        CCSize winSize = CCDirector::sharedDirector()->getWinSize();
        this ->_label = CCLabelTTF::labelWithString( "" , "Artial" ,32);
        this ->_label->retain();
        this ->_label->setColor(ccc3(0,0,0));
        this ->_label->setPosition(ccp(winSize.width/2,winSize.height/2));
        this ->addChild( this ->_label);

        this ->runAction(CCSequence::actions(CCDelayTime::actionWithDuration(3),
                                        CCCallFunc::actionWithTarget( this ,
                                        callfunc_selector(GameOverLayer::gameOverDone)),NULL));
        return true ;
    }
    else
    {
        return false ;
    }
}