Sprite添加触摸监听（实现跟随手指移动）

auto plane = Sprite::create("mplane.png");

auto touchListener = EventListenerTouchOneByOne::create();

    touchListener->onTouchBegan = CC_CALLBACK_2(PlanLayer::onTouchBegan, this);

    touchListener->onTouchMoved = CC_CALLBACK_2(PlanLayer::onTouchMoved, this);

    touchListener->onTouchEnded = CC_CALLBACK_2(PlanLayer::onTouchEnded, this);

    _eventDispatcher->addEventListenerWithSceneGraphPriority(touchListener,plane); 

bool PlanLayer::onTouchBegan(Touch *touch, Event *unused_event){

    auto target = static_cast<Sprite*>(unused_event->getCurrentTarget());//将派生类指针转化成基类

    Point locationInNode = target->convertToNodeSpace(touch->getLocation());//将世界坐标转化成节点坐标

    target->setPosition(touch->getLocation());

    return true;

}

void PlanLayer::onTouchMoved(Touch *touch, Event *unused_event){

    auto target = static_cast<Sprite*>(unused_event->getCurrentTarget());

    target->setPosition(touch->getLocation());

}

void PlanLayer::onTouchEnded(Touch *touch, Event *unused_event){

}