求助 触摸计数 为什么不好使呢

Cocos2d-x
#1

auto label = Label::createWithSystemFont(“Next Scene”, “Courier”, 30);
label->setPosition(visibleSize.width / 2, visibleSize.height / 2);

UINT nCount = 0;
EventListenerTouchOneByOne *listener = EventListenerTouchOneByOne::create();
listener->onTouchBegan = (Touch *t, Event *e){
    if (label->getBoundingBox().containsPoint(t->getLocation()))
    {            
        nCount = nCount + 1;
    }
    return true;
};
Director::getInstance()->getEventDispatcher()->
    addEventListenerWithSceneGraphPriority(listener, label);
addChild(label);

//nCount传进来并不是0，而且也没有自增，这是为啥呢？？？