cocos2dx 3.x(点击屏幕移动精灵，拖动精灵)不需要写回调函数Lua表达式

 //
 //  MainScene.cpp
 //  helloworld
 //
 //  Created by apple on 16/9/19.
 //
 //

 #include "MainScene.hpp"
 Scene * MainScene::createScene()
 {
      auto scene = Scene::create();
     //创建层
     MainScene *layer = MainScene::create();
     scene->addChild(layer);
     return scene;
 }
 bool MainScene::init(){
     if (!Layer::init()) {
         return false;
     }

     sprite = Sprite::create("hu.png");
     sprite ->setPosition(, );
     sprite->setAnchorPoint(Vec2(0.5, 0.5));
     this->addChild(sprite);// 添加到层

     //声明
     auto listener1 = EventListenerTouchOneByOne::create();
     listener1->setSwallowTouches(true);

     //通过 lambda 表达式 直接实现触摸事件的回掉方法
     listener1->onTouchBegan = [](Touch* touch, Event* event){
         auto target = static_cast<Sprite*>(event->getCurrentTarget());

         Point locationInNode = target->convertToNodeSpace(touch->getLocation());
         Size s = target->getContentSize();
         Rect rect = Rect(, , s.width, s.height);

         if (rect.containsPoint(locationInNode))
         {
             log("sprite began... x = %f, y = %f", locationInNode.x, locationInNode.y);
             target->setOpacity();//点击的时候精灵颜色变暗，255为最大值，0最小
             return true;
         }
         return false;
     };

     listener1->onTouchMoved = [](Touch* touch, Event* event){
         auto target = static_cast<Sprite*>(event->getCurrentTarget());
         target->setPosition(target->getPosition() + touch->getDelta());
     };

     listener1->onTouchEnded = [=](Touch* touch, Event* event){
         auto target = static_cast<Sprite*>(event->getCurrentTarget());
         log("sprite onTouchesEnded.. ");
         target->setOpacity();//手势松开时使精灵恢复原来的颜色
     };

     //将触摸事件绑定到精灵身上
     _eventDispatcher->addEventListenerWithSceneGraphPriority(listener1, sprite);
     _eventDispatcher->addEventListenerWithSceneGraphPriority(listener1->clone(), sprite);
     _eventDispatcher->addEventListenerWithSceneGraphPriority(listener1->clone(), sprite);

     return true;
 }