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;

 }