今天看了下ccocos2dx touch事件部分的源碼，從CCTouch、CCTouchHandler和CCTouchDispatcher簡單的做了分析和總結，先直接看源碼吧！
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;//獲取當前touch位置，該位置基於OpenGL坐標
/** returns the previous touch location in OpenGL coordinates */ CCPoint getPreviousLocation() const;//獲取前一次touch位置，該位置基於OpenGL坐標
/** returns the start touch location in OpenGL coordinates */ CCPoint getStartLocation() const;//獲取該touch的起始位置，該位置基於OpenGL坐標
/** returns the delta of 2 current touches locations in screen coordinates */ CCPoint getDelta() const; //獲取前后兩次位置的偏移量，基於OpenGL坐標
/** returns the current touch location in screen coordinates */ CCPoint getLocationInView() const; //當前touch位置,該位置基於屏幕坐標位置
/** returns the previous touch location in screen coordinates */ CCPoint getPreviousLocationInView() const; //獲取touch前一次的位置，基於屏幕坐標位置
/** returns the start touch location in screen coordinates */ CCPoint getStartLocationInView() const; //獲取touch起始位置，基於屏幕坐標位置
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中有三個主要成員，m_startPoint、m_point、m_prevPoint，這三個點都是基於屏幕坐標。將這三個點轉化為OpenGL坐標可以用CCDirector::sharedDirector()->convertToGL(m_point)函數來轉化。
2、CCTouchHandler、CCStandardTouchHandler和CCTargetedTouchHandler
class CC_DLL CCTouchHandler : public CCObject { public: virtual ~CCTouchHandler(void); /** delegate */ CCTouchDelegate* getDelegate(); //獲取touch代理
void setDelegate(CCTouchDelegate *pDelegate); //設置touch代理
/** priority */
int getPriority(void); //獲取代理優先級
void setPriority(int nPriority); //獲取代理優先級
/** 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 *///創建一個CCTouchHandler
static CCTouchHandler* handlerWithDelegate(CCTouchDelegate *pDelegate, int nPriority); protected: CCTouchDelegate *m_pDelegate; //touch代理
int m_nPriority; //優先級
int m_nEnabledSelectors; //該成員沒看出來有什么作用
}; CCTouchHandler主要將touch代理和優先級封裝起來，CCTouchHandler還有兩個派生對象: CCStandardTouchHandler和CCTargetedTouchHandler。這兩個派生類很簡單不需多說，簡單的貼上代碼吧。 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); //設置是否吞掉CCTouch
/** MutableSet that contains the claimed touches */ CCSet* getClaimedTouches(void); //獲取將要處理的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; //處理CCTouch后是否吞掉該CCTouch
CCSet *m_pClaimedTouches; //要處理的CCTouch集合
};
3、CCTouch事件分發器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); //事件是否要被分發
void setDispatchEvents(bool bDispatchEvents); //設置是否分發事件
/** 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); //向標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); //向目標代理容器添加代理
/** 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);//設置特定代理的優先級
void touches(CCSet *pTouches, CCEvent *pEvent, unsigned int uIndex); //分發事件邏輯處理，主要看的函數 //以下是對四種事件的處理
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); //根據代理查找特定CCTouchHandler
protected: void forceRemoveDelegate(CCTouchDelegate *pDelegate); void forceAddHandler(CCTouchHandler *pHandler, CCArray* pArray); void forceRemoveAllDelegates(void); void rearrangeHandlers(CCArray* pArray); //重新根據優先級對代理排序
CCTouchHandler* findHandler(CCArray* pArray, CCTouchDelegate *pDelegate); protected: CCArray* m_pTargetedHandlers; //目標事件代理容器
CCArray* m_pStandardHandlers; //標准事件代理容器
bool m_bLocked; //是否被鎖
bool m_bToAdd; //是否需要添加
bool m_bToRemove; //是否需要刪除
CCArray* m_pHandlersToAdd; //要添加的代理容器
struct _ccCArray *m_pHandlersToRemove; //要刪除的代理容器
bool m_bToQuit; //是否要退出
bool m_bDispatchEvents; //是否要處理touch事件 // 4, 1 for each type of event
struct ccTouchHandlerHelperData m_sHandlerHelperData[ccTouchMax]; };
我們主要看一看void touches(CCSet *pTouches, CCEvent *pEvent, unsigned int uIndex); 這個函數看看touch事件分發器是如何實現事件的分發。先貼上該函數源碼
void CCTouchDispatcher::touches(CCSet *pTouches, CCEvent *pEvent, unsigned int uIndex) { CCAssert(uIndex >= 0 && uIndex < 4, ""); //檢查4種touch事件的類型
CCSet *pMutableTouches; m_bLocked = true; //正在進行事件分發的時候先鎖定，避免代理容器內部發生變化 // optimization to prevent a mutable copy when it is not necessary
unsigned int uTargetedHandlersCount = m_pTargetedHandlers->count(); //獲取目標事件代理個數
unsigned int uStandardHandlersCount = m_pStandardHandlers->count(); //獲取標准事件代理個數
bool bNeedsMutableSet = (uTargetedHandlersCount && uStandardHandlersCount); //需不需要拷貝CCTouch容器
pMutableTouches = (bNeedsMutableSet ? pTouches->mutableCopy() : pTouches); //拷貝CCTouch容器用於向標准touch代理分發事件
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) //遍歷CCTouch集合
{ pTouch = (CCTouch *)(*setIter); CCTargetedTouchHandler *pHandler = NULL; CCObject* pObj = NULL; CCARRAY_FOREACH(m_pTargetedHandlers, pObj) //對於每一個CCTouch，遍歷每一個目標事件代理處理器
{ pHandler = (CCTargetedTouchHandler *)(pObj); if (! pHandler) { break; } bool bClaimed = false; //是否要得到處理
if (uIndex == CCTOUCHBEGAN) { bClaimed=pHandler->getDelegate()->ccTouchBegan(pTouch, pEvent);//調用代理的ccTouchBegan函數
if (bClaimed) //如果ccTouchBegan函數返回true,說明事件要被處理
{ pHandler->getClaimedTouches()->addObject(pTouch); //將該touch事件加入到該touch事件處理器的待處理事件容器中
} } else
if (pHandler->getClaimedTouches()->containsObject(pTouch)) //判斷handler內是否有該CCTouch
{ // moved ended canceled
bClaimed = true; //標記要被處理
switch (sHelper.m_type) { case CCTOUCHMOVED: pHandler->getDelegate()->ccTouchMoved(pTouch, pEvent); //注意處理CCTouchMoved 不會移除相應CCTouch
break; case CCTOUCHENDED: pHandler->getDelegate()->ccTouchEnded(pTouch, pEvent); pHandler->getClaimedTouches()->removeObject(pTouch); //從代理handler中的要處理的CCTouch容器中移除該CCTouch
break; case CCTOUCHCANCELLED: pHandler->getDelegate()->ccTouchCancelled(pTouch, pEvent); pHandler->getClaimedTouches()->removeObject(pTouch); //從代理handler中的要處理的CCTouch容器中移除該CCTouch
break; } } if (bClaimed && pHandler->isSwallowsTouches()) //已經被處理並且要吞掉
{ if (bNeedsMutableSet) // { pMutableTouches->removeObject(pTouch); //從用於向標准代理分發事件的容器中移除該CCTouch
} break; } } } } //
// process standard handlers 2nd //處理標准事件的分發，比目標事件簡單
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(); //釋放掉拷貝過來用於分發標准事件的touch集合
} //
// Optimization. To prevent a [handlers copy] which is expensive // the add/removes/quit is done after the iterations // m_bLocked = false; //解除鎖定
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(); //刪除所有代理
} }
從代碼中我們可以清楚的看到時間分發的邏輯，cocos2dx將代理分為兩種類型：標准事件代理和目標事件代理，事件分發的時候分別處理；事件分為四種事件，CCTOUCHBEGAN、CCTOUCHMOVED、CCTOUCHENDED和CCTOUCHCANCELLED；當調用目標代理的ccTouchBegan函數返回為真說明改代理需要處理該事件，並將該事件暫存到CCTargetedTouchHandler得集合中，當調用ccTouchMoved、ccTouchEnded和ccTouchCanceled時若該代理是否要吞掉該事件則刪除標准容器中的該事件。標准事件的分發比較簡單略過，還有一點就是，cocos2dx在進行事件分發的時候，將兩種容器鎖定，避免分發事件的時候容器中的代理有變化，事件分發結束后再將該添加的代理添加，該刪除的代理刪除。
4、CCTouch、CCTouchHandler和CCTouchDispatcher之間的關系如下圖所示：
