在cocos2dx 3.0版本中,废弃了以往2.x版本的写法,我们先来看一下Layer.h中的一段代码
- /*
- Callback function should not be deprecated,it will generate lots of warnings.
- Since 'setTouchEnabled' was deprecated,it will make warnings if developer
- overrides onTouchXXX and invokes setTouchEnabled(true) instead of using
- EventDispatcher::addEventListenerWithXXX.
- */
- //单点触摸
- virtual bool onTouchBegan(Touch *touch,Event *unused_event);
- virtual void onTouchMoved(Touch *touch,Event *unused_event);
- virtual void onTouchEnded(Touch *touch,Event *unused_event);
- virtual void onTouchCancelled(Touch *touch,Event *unused_event);
- //多点触摸
- virtual void onTouchesBegan(const std::vector<Touch*>& touches,Event *unused_event);
- virtual void onTouchesMoved(const std::vector<Touch*>& touches,Event *unused_event);
- virtual void onTouchesEnded(const std::vector<Touch*>& touches,Event *unused_event);
- virtual void onTouchesCancelled(const std::vector<Touch*>&touches,Event *unused_event);
单点触摸:(即只有注册的Layer才能接收触摸事件)
onTouchBegan:如果返回true:本层的后续Touch事件可以被触发,并阻挡向后层传递
如果返回false,本层的后续Touch事件不能被触发,并向后传递
简单点来说,如果
1.Layer 只有一层的情况:
virtualboolonTouchBegan(CCTouch*pTouch,CCEvent*pEvent);
a.返回false,则ccTouchMoved(),ccTouchEnded()不会再接收到消息
b.返回true,则ccTouchMoved(),ccTouchEnded()可以接收到消息
2.Layer 有多层的情况:
CCEvent*pEvent);
a.返回false,则本层的onTouchMoved(),onTouchEnded()不会再接收到消息,但是本层之下的其它层会接收到消息
b.返回true,则本层的onTouchMoved(),onTouchEnded()可以接收到消息,但是本层之下的其它层不能再接收到消息
单点触摸简单用法:
- auto dispatcher = Director::getInstance()->getEventDispatcher();
- auto listener = EventListenerTouchOneByOne::create();
- listener->onTouchBegan = CC_CALLBACK_2(GameLayer::onTouchBegan,this);
- listener->onTouchMoved = CC_CALLBACK_2(GameLayer::onTouchMoved,this);
- listener->onTouchEnded = CC_CALLBACK_2(GameLayer::onTouchEnded,this);
- listener->setSwallowTouches(true);//不向下传递触摸
- dispatcher->addEventListenerWithSceneGraPHPriority(listener,this);
listener->setSwallowTouches(true),不向下触摸,简单点来说,比如有两个sprite,A 和 B,A在上B在下(位置重叠),触摸A的时候,B不会受到影响
listener->setSwallowTouches(false)反之,向下传递触摸,触摸A也等于触摸了B
- auto dispatcher = Director::getInstance()->getEventDispatcher();
- auto listener1 = EventListenerTouchAllAtOnce::create();
- listener1->onTouchesBegan = CC_CALLBACK_2(GameLayer::onTouchesBegan,this);
- listener1->onTouchesMoved = CC_CALLBACK_2(GameLayer::onTouchesMoved,this);
- listener1->onTouchesEnded = CC_CALLBACK_2(GameLayer::onTouchesEnded,this);
- dispatcher->addEventListenerWithSceneGraPHPriority(listener1,this);
或者setTouchEnabled(true),然后重写layer的onTouchsxxx函数
关于eventDispatcher:
- auto dispatcher = Director::getInstance()->getEventDispatcher();
事件监听器包含以下几种:
- 触摸事件 (EventListenerTouch)
- 键盘响应事件 (EventListenerKeyboard)
- 加速记录事件 (EventListenerAcceleration)
- 鼠标响应事件 (EventListenerMouse)
- 自定义事件 (EventListenerCustom)
以上事件监听器统一由
_eventDispatcher
来进行管理。
优先权:
1.优先级越低,越先响应事件
2.如果优先级相同,则上层的(z轴)先接收触摸事件
有两种方式将 事件监听器 listener1 添加到 事件调度器_eventDispatcher 中:
- void EventDispatcher::addEventListenerWithSceneGraPHPriority(EventListener* listener,Node* node);
- void EventDispatcher::addEventListenerWithFixedPriority(EventListener* listener,int fixedPriority);
代码展开一下:
- void EventDispatcher::addEventListenerWithSceneGraPHPriority(EventListener* listener,Node* node)
- {
- CCASSERT(listener && node,"Invalid parameters.");
- CCASSERT(!listener->isRegistered(),"The listener has been registered.");
- if (!listener->checkAvailable())
- return;
- listener->setSceneGraPHPriority(node);
- listener->setFixedPriority(0);
- listener->setRegistered(true);
- addEventListener(listener);
- }
- void EventDispatcher::addEventListenerWithFixedPriority(EventListener* listener,int fixedPriority)
- {
- CCASSERT(listener,"The listener has been registered.");
- CCASSERT(fixedPriority != 0,"0 priority is forbidden for fixed priority since it's used for scene graph based priority.");
- if (!listener->checkAvailable())
- return;
- listener->setSceneGraPHPriority(nullptr);
- listener->setFixedPriority(fixedPriority);
- listener->setRegistered(true);
- listener->setPaused(false);
- addEventListener(listener);
- }
(1)addEventListenerWithSceneGraPHPriority 的事件监听器优先级是0,而且在 addEventListenerWithFixedPriority 中的事件监听器的优先级不可以设置为 0,因为这个是保留给 SceneGraPHPriority 使用的。
(2)另外,有一点非常重要,FixedPriority listener添加完之后需要手动remove,而SceneGraPHPriority listener是跟node绑定的,在node的析构函数中会被移除。
移除方法:
- dispatcher->removeEventListener(listener);