Cocos2dx之touch事件

今天看了下ccocos2dx touch事件部分的源码，从CCTouch、CCTouchHandler和CCTouchDispatcher简单的做了分析和总结，先直接看源码吧！

1、CCTouch

class CC_DLL CCTouch : public CCObject { public: CCTouch() : m_nId(0), m_startPointCaptured(false) {} /** returns the current touch location in OpenGL coordinates */ CCPoint getLocation() const;//获取当前touch位置，该位置基于OpenGL坐标

    /** returns the previous touch location in OpenGL coordinates */ CCPoint getPreviousLocation() const;//获取前一次touch位置，该位置基于OpenGL坐标

    /** returns the start touch location in OpenGL coordinates */ CCPoint getStartLocation() const;//获取该touch的起始位置，该位置基于OpenGL坐标

    /** returns the delta of 2 current touches locations in screen coordinates */ CCPoint getDelta() const;  //获取前后两次位置的偏移量，基于OpenGL坐标

    /** returns the current touch location in screen coordinates */ CCPoint getLocationInView() const; //当前touch位置,该位置基于屏幕坐标位置

    /** returns the previous touch location in screen coordinates */ CCPoint getPreviousLocationInView() const; //获取touch前一次的位置，基于屏幕坐标位置

    /** returns the start touch location in screen coordinates */ CCPoint getStartLocationInView() const;  //获取touch起始位置，基于屏幕坐标位置

    

    void setTouchInfo(int id, float x, float y) { m_nId = id; m_prevPoint = m_point; m_point.x = x; m_point.y = y; if (!m_startPointCaptured) { m_startPoint = m_point; m_startPointCaptured = true; } } int getID() const { return m_nId; } private: int m_nId; bool m_startPointCaptured; CCPoint m_startPoint; CCPoint m_point; CCPoint m_prevPoint; };

CCTouch中有三个主要成员，m_startPoint、m_point、m_prevPoint，这三个点都是基于屏幕坐标。将这三个点转化为OpenGL坐标可以用CCDirector::sharedDirector()->convertToGL(m_point)函数来转化。

2、CCTouchHandler、CCStandardTouchHandler和CCTargetedTouchHandler

class CC_DLL  CCTouchHandler : public CCObject { public: virtual ~CCTouchHandler(void); /** delegate */ CCTouchDelegate* getDelegate();    //获取touch代理

    void setDelegate(CCTouchDelegate *pDelegate); //设置touch代理



    /** priority */

    int getPriority(void);    //获取代理优先级

    void setPriority(int nPriority); //获取代理优先级



    /** enabled selectors */

    int getEnabledSelectors(void); //     void setEnalbedSelectors(int nValue); /** initializes a TouchHandler with a delegate and a priority */

    virtual bool initWithDelegate(CCTouchDelegate *pDelegate, int nPriority); public: /** allocates a TouchHandler with a delegate and a priority *///创建一个CCTouchHandler

static CCTouchHandler* handlerWithDelegate(CCTouchDelegate *pDelegate, int nPriority); protected: CCTouchDelegate *m_pDelegate;     //touch代理

    int m_nPriority;            //优先级

    int m_nEnabledSelectors;      //该成员没看出来有什么作用

}; CCTouchHandler主要将touch代理和优先级封装起来，CCTouchHandler还有两个派生对象: CCStandardTouchHandler和CCTargetedTouchHandler。这两个派生类很简单不需多说，简单的贴上代码吧。 class CC_DLL  CCStandardTouchHandler : public CCTouchHandler { public: /** initializes a TouchHandler with a delegate and a priority */

    virtual bool initWithDelegate(CCTouchDelegate *pDelegate, int nPriority); public: /** allocates a TouchHandler with a delegate and a priority */

    static CCStandardTouchHandler* handlerWithDelegate(CCTouchDelegate *pDelegate, int nPriority); }; class CC_DLL  CCTargetedTouchHandler : public CCTouchHandler { public: ~CCTargetedTouchHandler(void); /** whether or not the touches are swallowed */

    bool isSwallowsTouches(void);        //是否吞掉CCTouch

    void setSwallowsTouches(bool bSwallowsTouches);  //设置是否吞掉CCTouch



    /** MutableSet that contains the claimed touches */ CCSet* getClaimedTouches(void);          //获取将要处理的CCTouch的集合



    /** initializes a TargetedTouchHandler with a delegate, a priority and whether or not it swallows touches or not */

    bool initWithDelegate(CCTouchDelegate *pDelegate, int nPriority, bool bSwallow); public: /** allocates a TargetedTouchHandler with a delegate, a priority and whether or not it swallows touches or not */

    static CCTargetedTouchHandler* handlerWithDelegate(CCTouchDelegate *pDelegate, int nPriority, bool bSwallow); protected: bool m_bSwallowsTouches;      //处理CCTouch后是否吞掉该CCTouch

    CCSet *m_pClaimedTouches;     //要处理的CCTouch集合

};

3、CCTouch事件分发器CCTouchDispatcher

class CC_DLL CCTouchDispatcher : public CCObject, public EGLTouchDelegate { public: ~CCTouchDispatcher(); bool init(void); CCTouchDispatcher() : m_pTargetedHandlers(NULL) , m_pStandardHandlers(NULL) , m_pHandlersToAdd(NULL) , m_pHandlersToRemove(NULL) {} public: /** Whether or not the events are going to be dispatched. Default: true */

    bool isDispatchEvents(void);           //事件是否要被分发

    void setDispatchEvents(bool bDispatchEvents);  //设置是否分发事件



    /** Adds a standard touch delegate to the dispatcher's list. See StandardTouchDelegate description. IMPORTANT: The delegate will be retained. */

    void addStandardDelegate(CCTouchDelegate *pDelegate, int nPriority);    //向标准代理容器添加代理



    /** Adds a targeted touch delegate to the dispatcher's list. See TargetedTouchDelegate description. IMPORTANT: The delegate will be retained. */

    void addTargetedDelegate(CCTouchDelegate *pDelegate, int nPriority, bool bSwallowsTouches); //向目标代理容器添加代理



    /** Removes a touch delegate. The delegate will be released */

    void removeDelegate(CCTouchDelegate *pDelegate);//移除特定代理



    /** Removes all touch delegates, releasing all the delegates */

    void removeAllDelegates(void);//移除所有代理



    /** Changes the priority of a previously added delegate. The lower the number, the higher the priority */

    void setPriority(int nPriority, CCTouchDelegate *pDelegate);//设置特定代理的优先级



    void touches(CCSet *pTouches, CCEvent *pEvent, unsigned int uIndex);  //分发事件逻辑处理，主要看的函数 //以下是对四种事件的处理

    virtual void touchesBegan(CCSet* touches, CCEvent* pEvent); virtual void touchesMoved(CCSet* touches, CCEvent* pEvent); virtual void touchesEnded(CCSet* touches, CCEvent* pEvent); virtual void touchesCancelled(CCSet* touches, CCEvent* pEvent); public: CCTouchHandler* findHandler(CCTouchDelegate *pDelegate);  //根据代理查找特定CCTouchHandler

protected: void forceRemoveDelegate(CCTouchDelegate *pDelegate); void forceAddHandler(CCTouchHandler *pHandler, CCArray* pArray); void forceRemoveAllDelegates(void); void rearrangeHandlers(CCArray* pArray);      //重新根据优先级对代理排序

    CCTouchHandler* findHandler(CCArray* pArray, CCTouchDelegate *pDelegate); protected: CCArray* m_pTargetedHandlers;     //目标事件代理容器

     CCArray* m_pStandardHandlers;     //标准事件代理容器



    bool m_bLocked;      //是否被锁

    bool m_bToAdd;      //是否需要添加

    bool m_bToRemove;   //是否需要删除

     CCArray* m_pHandlersToAdd; //要添加的代理容器

    struct _ccCArray *m_pHandlersToRemove; //要删除的代理容器

    bool m_bToQuit;     //是否要退出

    bool m_bDispatchEvents;  //是否要处理touch事件 // 4, 1 for each type of event

    struct ccTouchHandlerHelperData m_sHandlerHelperData[ccTouchMax]; };

我们主要看一看void touches(CCSet *pTouches, CCEvent *pEvent, unsigned int uIndex); 这个函数看看touch事件分发器是如何实现事件的分发。先贴上该函数源码

void CCTouchDispatcher::touches(CCSet *pTouches, CCEvent *pEvent, unsigned int uIndex) { CCAssert(uIndex >= 0 && uIndex < 4, "");   //检查4种touch事件的类型

 CCSet *pMutableTouches; m_bLocked = true;                      //正在进行事件分发的时候先锁定，避免代理容器内部发生变化 // optimization to prevent a mutable copy when it is not necessary

     unsigned int uTargetedHandlersCount = m_pTargetedHandlers->count();    //获取目标事件代理个数

     unsigned int uStandardHandlersCount = m_pStandardHandlers->count();    //获取标准事件代理个数

    bool bNeedsMutableSet = (uTargetedHandlersCount && uStandardHandlersCount); //需不需要拷贝CCTouch容器

 pMutableTouches = (bNeedsMutableSet ? pTouches->mutableCopy() : pTouches);   //拷贝CCTouch容器用于向标准touch代理分发事件



    struct ccTouchHandlerHelperData sHelper = m_sHandlerHelperData[uIndex]; //

    // process the target handlers 1st //     if (uTargetedHandlersCount > 0) { CCTouch *pTouch; CCSetIterator setIter; for (setIter = pTouches->begin(); setIter != pTouches->end(); ++setIter)     //遍历CCTouch集合

 { pTouch = (CCTouch *)(*setIter); CCTargetedTouchHandler *pHandler = NULL; CCObject* pObj = NULL; CCARRAY_FOREACH(m_pTargetedHandlers, pObj) //对于每一个CCTouch，遍历每一个目标事件代理处理器

 { pHandler = (CCTargetedTouchHandler *)(pObj); if (! pHandler) { break; } bool bClaimed = false;        //是否要得到处理

                if (uIndex == CCTOUCHBEGAN) { bClaimed=pHandler->getDelegate()->ccTouchBegan(pTouch, pEvent);//调用代理的ccTouchBegan函数

                    if (bClaimed)    //如果ccTouchBegan函数返回true,说明事件要被处理

 { pHandler->getClaimedTouches()->addObject(pTouch);   //将该touch事件加入到该touch事件处理器的待处理事件容器中

 } } else

                if (pHandler->getClaimedTouches()->containsObject(pTouch))     //判断handler内是否有该CCTouch

 { // moved ended canceled

                    bClaimed = true;       //标记要被处理



                    switch (sHelper.m_type) { case CCTOUCHMOVED: pHandler->getDelegate()->ccTouchMoved(pTouch, pEvent);   //注意处理CCTouchMoved 不会移除相应CCTouch

                        break; case CCTOUCHENDED: pHandler->getDelegate()->ccTouchEnded(pTouch, pEvent); pHandler->getClaimedTouches()->removeObject(pTouch);     //从代理handler中的要处理的CCTouch容器中移除该CCTouch

                        break; case CCTOUCHCANCELLED: pHandler->getDelegate()->ccTouchCancelled(pTouch, pEvent); pHandler->getClaimedTouches()->removeObject(pTouch);     //从代理handler中的要处理的CCTouch容器中移除该CCTouch

                        break; } } if (bClaimed && pHandler->isSwallowsTouches())   //已经被处理并且要吞掉

 { if (bNeedsMutableSet)     //  { pMutableTouches->removeObject(pTouch);   //从用于向标准代理分发事件的容器中移除该CCTouch

 } break; } } } } //

    // process standard handlers 2nd //处理标准事件的分发，比目标事件简单

    if (uStandardHandlersCount > 0 && pMutableTouches->count() > 0) { CCStandardTouchHandler *pHandler = NULL; CCObject* pObj = NULL; CCARRAY_FOREACH(m_pStandardHandlers, pObj) { pHandler = (CCStandardTouchHandler*)(pObj); if (! pHandler) { break; } switch (sHelper.m_type) { case CCTOUCHBEGAN: pHandler->getDelegate()->ccTouchesBegan(pMutableTouches, pEvent); break; case CCTOUCHMOVED: pHandler->getDelegate()->ccTouchesMoved(pMutableTouches, pEvent); break; case CCTOUCHENDED: pHandler->getDelegate()->ccTouchesEnded(pMutableTouches, pEvent); break; case CCTOUCHCANCELLED: pHandler->getDelegate()->ccTouchesCancelled(pMutableTouches, pEvent); break; } } } if (bNeedsMutableSet) { pMutableTouches->release();   //释放掉拷贝过来用于分发标准事件的touch集合

 } //

    // Optimization. To prevent a [handlers copy] which is expensive // the add/removes/quit is done after the iterations //     m_bLocked = false;    //解除锁定

    if (m_bToRemove)    //有需要被移除的代理

 { m_bToRemove = false; for (unsigned int i = 0; i < m_pHandlersToRemove->num; ++i) { forceRemoveDelegate((CCTouchDelegate*)m_pHandlersToRemove->arr[i]); } ccCArrayRemoveAllValues(m_pHandlersToRemove); } if (m_bToAdd)   //有需要被添加的代理

 { m_bToAdd = false; CCTouchHandler* pHandler = NULL; CCObject* pObj = NULL; CCARRAY_FOREACH(m_pHandlersToAdd, pObj) { pHandler = (CCTouchHandler*)pObj; if (! pHandler) { break; } if (dynamic_cast<CCTargetedTouchHandler*>(pHandler) != NULL) { forceAddHandler(pHandler, m_pTargetedHandlers); } else { forceAddHandler(pHandler, m_pStandardHandlers); } } m_pHandlersToAdd->removeAllObjects(); } if (m_bToQuit)   //需要退出

 { m_bToQuit = false; forceRemoveAllDelegates(); //删除所有代理

 } }

　　从代码中我们可以清楚的看到时间分发的逻辑，cocos2dx将代理分为两种类型：标准事件代理和目标事件代理，事件分发的时候分别处理；事件分为四种事件，CCTOUCHBEGAN、CCTOUCHMOVED、CCTOUCHENDED和CCTOUCHCANCELLED；当调用目标代理的ccTouchBegan函数返回为真说明改代理需要处理该事件，并将该事件暂存到CCTargetedTouchHandler得集合中，当调用ccTouchMoved、ccTouchEnded和ccTouchCanceled时若该代理是否要吞掉该事件则删除标准容器中的该事件。标准事件的分发比较简单略过，还有一点就是，cocos2dx在进行事件分发的时候，将两种容器锁定，避免分发事件的时候容器中的代理有变化，事件分发结束后再将该添加的代理添加，该删除的代理删除。

4、CCTouch、CCTouchHandler和CCTouchDispatcher之间的关系如下图所示：