Cocos2dx Sprite drop and drag

example.cpp

#include "example.h"

USING_NS_CC;

// createScene create scene for main scene
Scene* ExampleScene ::createScene()
{
    return ExampleScene ::create();
}

// init on "init" you need to initialize your instance
bool ExampleScene ::init()
{
    //////////////////////////////
    // 1. super init first
    if (!Scene::init())
    {
        return false;
    }
auto visibleSize = Director::getInstance()->getVisibleSize();
Vec2 origin = Director::getInstance()->getVisibleOrigin();

// 初始化sprite
_spriteToMove = Sprite::create("Example.png");
// sprite 位置置中
_spriteToMove->setPosition(Point(visibleSize.width / 2 + origin.x, visibleSize.height / 2 + origin.y));
// 將sprite加入到ExampleScene
this->addChild(_spriteToMove);
// 創建觸控監聽器
EventListenerTouchOneByOne *listener = EventListenerTouchOneByOne::create();
// 利用CC_CALLBACK_2綁定函數
listener->onTouchBegan = CC_CALLBACK_2(MainScene::onTouchBegan,this);
listener->onTouchMoved = CC_CALLBACK_2(MainScene::onTouchMoved,this);
// 加入監聽至事件分配
_eventDispatcher->addEventListenerWithSceneGraphPriority(listener, this);

return true;
}

// onTouchBegan 必須實作否則會報錯
bool ExampleScene ::onTouchBegan(cocos2d::Touch *touch, cocos2d::Event *event)
{
    return true;
};

// 利用每次的變化量設定sprite位置
void ExampleScene ::onTouchMoved(cocos2d::Touch *touch, cocos2d::Event *event)
{
    _spriteToMove->setPosition(_spriteToMove->getPosition() + touch->getDelta());
};

example.h

#ifndef __Example_SCENE_H__
#define __Example_SCENE_H__

#include "cocos2d.h"

class ExampleScene : public cocos2d::Scene
{
public:
    static cocos2d::Scene* createScene();

    virtual bool init();

    CREATE_FUNC(ExampleScene );
        
    // 需要綁定的函數
    bool onTouchBegan(cocos2d::Touch *touch, cocos2d::Event *event);
    void onTouchMoved(cocos2d::Touch *touch, cocos2d::Event *event);
private:
    // 目標sprite
    cocos2d::Sprite *_spriteToMove;
};

#endif // __Example_SCENE_H__