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：
