cocos2dx触摸事件问题

Question

1. 下面是教程中正确的代码

2.    bool TowerPanleLayer::init()

   {

      if(!Layer::init())
      {
          return false;
      }
         //初始化缓存帧
      auto cache = SpriteFrameCache::sharedSpriteFrameCache();
      cache->addSpriteFramesWithFile("TArrow-hd.plist","TArrow-hd.png");
      cache->addSpriteFramesWithFile("TPin-hd.plist","TPin-hd.png");
      cache->addSpriteFramesWithFile("TSun-hd.plist","TSun-hd.png");
         //定义菜单精灵
      this->sprite = Sprite::createWithSpriteFrame(cache->spriteFrameByName("select_01.png"));
      this->addChild(sprite,0);
          //定义菜单项精灵
      this->sprite1 = Sprite::createWithSpriteFrame(cache->spriteFrameByName("Arrow01.png"));
      this->sprite1->setPosition(- this->sprite1->getContentSize().width,- this->sprite1->getContentSize().height);
      this->addChild(sprite1,1);
   
      this->sprite2 = Sprite::createWithSpriteFrame(cache->spriteFrameByName("Pin01.png"));
      this->sprite2->setPosition(0,- this->sprite2->getContentSize().height);
      this->addChild(sprite2,1);
   
      this->sprite3 = Sprite::createWithSpriteFrame(cache->spriteFrameByName("Sun01.png"));
      this->sprite3->setPosition(this->sprite3->getContentSize().width,- this->sprite3->getContentSize().height);
      this->addChild(sprite3,1);
      //监听器
      auto touchListener = EventListenerTouchOneByOne::create();
      touchListener->setSwallowTouches(true);
      touchListener->onTouchBegan = CC_CALLBACK_2(TowerPanleLayer::onTouchBegan,this);
      touchListener->onTouchEnded = CC_CALLBACK_2(TowerPanleLayer::onTouchEnded,this);
          //到下面这个位置，我就不懂了
      _eventDispatcher->addEventListenerWithSceneGraphPriority(touchListener,sprite1);
      _eventDispatcher->addEventListenerWithSceneGraphPriority(touchListener->clone(),sprite2);
      _eventDispatcher->addEventListenerWithSceneGraphPriority(touchListener->clone(),sprite3);    
      return true;

   }

   bool TowerPanleLayer::onTouchBegan(Touch touch,Event event)
   {

      auto target = static_cast<Sprite*>(event->getCurrentTarget());
      
      Point locationInNode = target->convertTouchToNodeSpace(touch);
      Size size = target->getContentSize();
      Rect rect = Rect(0, 0, size.width, size.height);
      
      if (rect.containsPoint(locationInNode))
      {
          target->setOpacity(180);
          return true;
      }
      return false;
      //return true;

   }

   void TowerPanleLayer::onTouchEnded(Touch touch,Event event)
   {

      auto tagert = static_cast<Sprite*>(event->getCurrentTarget());
      if(tagert == sprite1)
      {
          this->setChooseTower(ARROW);
      }
      else if(tagert == sprite2)
      {
          this->setChooseTower(PIN);
      }
      else if(tagert == sprite3)
      {
          this->setChooseTower(SUN);
      }
      else 
      {
          this->setChooseTower(ANOTHER);
      }

   }

3.当我修改代码后就不对了,无论我点哪个菜单选项，都会选在sprite3上

bool TowerPanleLayer::onTouchBegan(Touch* touch,Event* event)
{
    //auto target = static_cast<Sprite*>(event->getCurrentTarget());
    //Point locationInNode = target->convertTouchToNodeSpace(touch);
    //Size size = target->getContentSize();
    //Rect rect = Rect(0, 0, size.width, size.height);
    //if (rect.containsPoint(locationInNode))
    //{
    //    target->setOpacity(180);
    //    return true;
    //}
    //return false;
    return true;
}

我觉得我注释掉的代码可有可无，但为什么不能去掉。
我注释掉的代码的作用是什么？
谢谢您阅读到这。

Answer 1

auto target = static_cast<Sprite*>(event->getCurrentTarget());//获取到你点击的对象具体是哪个精灵
Point locationInNode = target->convertTouchToNodeSpace(touch);//获取到点击位置在你这个对象的相对位置
Size size = target->getContentSize();//对象内容大小，在后面用来判断是否点中了某对象的区域
Rect rect = Rect(0, 0, size.width, size.height);//包含这个对象的矩形区域
if (rect.containsPoint(locationInNode))//矩形局域检测，点是否在矩形内部
{//在内部就执行下面，设置透明度给你看到，并且前面设置了吞噬（setSwallowTouches），那么这里传递return true会传递消息到你的onTouchEnded，并且其他注册了精灵对象的会收不到点击事件了，被吞噬了。
    target->setOpacity(180);
    return true;
}
return false;

希望对你有用！

Answer 2

onTouchBegan返回值决定是否将按键响应延场景树往下传。原来的代码用于判断有没有按到sprite 上。按到了刚设置半透明并不再往下传了，去掉判断后强制响应场景中最后的sprite3并不再往下传事件了。