cocos2dx 点击事件分析（5）

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经过CCEGLViewProtocol的handleTouchesBegin，handleTouchesMove，handleTouchesEnd，handleTouchesCancel处理，
都会CCTouchDispatcher中的下面这些函数，而且都会调用touches，那我们就分析一下touches这个函数
void CCTouchDispatcher::touchesBegan(CCSet *touches, CCEvent *pEvent)
{
    if (m_bDispatchEvents)
    {
        this->touches(touches, pEvent, CCTOUCHBEGAN);
    }
}

void CCTouchDispatcher::touchesMoved(CCSet *touches, CCEvent *pEvent)
{
    if (m_bDispatchEvents)
    {
        this->touches(touches, pEvent, CCTOUCHMOVED);
    }
}

void CCTouchDispatcher::touchesEnded(CCSet *touches, CCEvent *pEvent)
{
    if (m_bDispatchEvents)
    {
        this->touches(touches, pEvent, CCTOUCHENDED);
    }
}

void CCTouchDispatcher::touchesCancelled(CCSet *touches, CCEvent *pEvent)
{
    if (m_bDispatchEvents)
    {
        this->touches(touches, pEvent, CCTOUCHCANCELLED);
    }
}

//
// dispatch events 分发触摸事件
//
//CCSet *pTouches 所有触摸点的信息
//*pEvent NULL
//uIndex 触摸类型：CCTOUCHBEGAN,CCTOUCHCANCELLED ....
void CCTouchDispatcher::touches(CCSet *pTouches, CCEvent *pEvent, unsigned int uIndex)
{
    CCAssert(uIndex >= 0 && uIndex < 4, "");

    CCSet *pMutableTouches;
    m_bLocked = true;

    // optimization to prevent a mutable copy when it is not necessary
    //判断是否需要copy
     unsigned int uTargetedHandlersCount = m_pTargetedHandlers->count();
     unsigned int uStandardHandlersCount = m_pStandardHandlers->count();
    bool bNeedsMutableSet = (uTargetedHandlersCount && uStandardHandlersCount);

    pMutableTouches = (bNeedsMutableSet ? pTouches->mutableCopy() : pTouches);

    struct ccTouchHandlerHelperData sHelper = m_sHandlerHelperData[uIndex];
    //
    // process the target handlers 1st
    //先处理target触摸事件
    if (uTargetedHandlersCount > 0)
    {
        CCTouch *pTouch;
        CCSetIterator setIter;
	//因为这里可能同时发过来几个手指的触摸行为，以前分析过CCTOUCHBEGAN和CCTOUCHENDED每次只会传递一个
	//多个手指不可能同时按下，总有先后
        for (setIter = pTouches->begin(); setIter != pTouches->end(); ++setIter)
        {
            pTouch = (CCTouch *)(*setIter);

            CCTargetedTouchHandler *pHandler = NULL;
            CCObject* pObj = NULL;
	    //遍历所有的TargetedHandler
            CCARRAY_FOREACH(m_pTargetedHandlers, pObj)
            {
                pHandler = (CCTargetedTouchHandler *)(pObj);

                if (! pHandler)
                {
                   break;
                }
		
		//任何一次触摸事件都是从CCTOUCHBEGAN开始的，如何没有begin那，后面的move，end等等就没有意义
		//那么如何表明，你对触摸事件感兴趣呢？就是在ccTouchBegan，即处理begin事件时返回true，那么表明
		//控件对这个事件感兴趣，claimed(认领，宣称的意思)，如果对begin不感兴趣，那么后面的move，end等就
		//不发给你了。
                bool bClaimed = false;
                if (uIndex == CCTOUCHBEGAN)
                {
                    bClaimed = pHandler->getDelegate()->ccTouchBegan(pTouch, pEvent);

                    if (bClaimed)
                    {
                        pHandler->getClaimedTouches()->addObject(pTouch);
                    }
                } else
                if (pHandler->getClaimedTouches()->containsObject(pTouch))
                {
                    // moved ended canceled
                    bClaimed = true;

                    switch (sHelper.m_type)
                    {
                    case CCTOUCHMOVED:
                        pHandler->getDelegate()->ccTouchMoved(pTouch, pEvent);
                        break;
                    case CCTOUCHENDED:
                        pHandler->getDelegate()->ccTouchEnded(pTouch, pEvent);
                        pHandler->getClaimedTouches()->removeObject(pTouch);
                        break;
                    case CCTOUCHCANCELLED:
                        pHandler->getDelegate()->ccTouchCancelled(pTouch, pEvent);
                        pHandler->getClaimedTouches()->removeObject(pTouch);
                        break;
                    }
                }
		
		//m_pTargetedHandlers链表的优先级从高到低，而且具有吞噬性，
		//即如果一个高优先级控件的处理了一次手指点击的CCTOUCHBEGAN事件，而且，
		//这个控件设置了Swallow，那么低优先级的控件都不能处理此时触摸事件
		//而且，还会把这次触摸事件从pMutableTouches多点触摸里面移除。
                if (bClaimed && pHandler->isSwallowsTouches())
                {
                    if (bNeedsMutableSet)
                    {
                        pMutableTouches->removeObject(pTouch);
                    }

                    break;
                }
            }
        }
    }

    //
    // process standard handlers 2nd
    //标准触摸事件，也是有优先级，但是没有吞噬能力。
    //所有的都可以接收
    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();
    }

    //
    // Optimization. To prevent a [handlers copy] which is expensive
    // the add/removes/quit is done after the iterations
    // 对那些当时因为m_bLocked而没有移除，增加的都加进事件处理链表中。
    //
    m_bLocked = false;
    if (m_bToRemove)
    {
        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)
    {
        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)
    {
        m_bToQuit = false;
        forceRemoveAllDelegates();
    }
}

cocos2dx 点击事件分析（5）

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原文地址：http://blog.csdn.net/tianxiawuzhei/article/details/44755541