生命游戏（两），有一种东西叫CCScrollView

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mb5ff40c7a158f2 2015-07-07 15:39:00

文章标签 lua 指定位置 c++ 属性设置 #include 文章分类 代码人生

订婚app要么game'肯定不会陌生：CCScrollView并且CCTableView。

假如我不知道是什么CCScrollView，再看看testcpp要么testlua样品棒。

先说说CCScrollView：.cpp和.h文件在\cocos2d-x-2.2.3\extensions\GUI\文件夹下，所以要使用CCScrollView首先要引入头文件#include "cocos-ext.h"，以及空间名USING_NS_CC_EXT; 假设头文件报错，那么请检查project的配置。这里就不多说了无非是引用，link的输入和c/c++里面的附加包括文件夹。（ps：假设是个简单的project个人建议你又一次建个新project）。

#include "cocos-ext.h"
USING_NS_CC_EXT;
void HelloWorld::initScroll(){
  CCSize size = CCDirector::sharedDirector()->getWinSize();
  CCScrollView* scroll = CCScrollView::create(size); //scroll->setViewSize(size);
  scroll->setDirection(kCCScrollViewDirectionVertical);  //设置滚动方向
  CCSprite* p1 = CCSprite::create("HelloWorld.png");
  p1->ignoreAnchorPointForPosition(true);
  CCSprite* p2 = CCSprite::create("HelloWorld.png");
  p2->setPosition(ccp(0,size.height));
  p2->ignoreAnchorPointForPosition(true);
  CCLayer* conLayer = CCLayer::create();
  conLayer->addChild(p1);
  conLayer->addChild(p2);
  scroll->setContainer(conLayer);
  scroll->setContentSize(CCSizeMake(size.width,320*2));
  this->addChild(scroll);
}

执行以上代码。我们就能够使用Scrollview了，总结起来就是

1、create scrollview

2、create Container层

3、将内容add到containner层

4、container层add到scrollview，scrollview增加指定layer或者scene

这里有几个点须要注意：

1、setContentSize不是scrollview大小，而是可滑动面的大小，viewSize是滑动面大小。

2、setContentSize不能放在setContainer前面，假设放在前面。那么这个滑动后回自己主动回到第一页。

3、container层中的内容position须要手动设定

4、假设不create container层，那么CCScrollView会给你创建个一个，可是直接在scrollview下add多个node仅仅会保留一个，原因在后面分析。

好了。最easy的部分写完了，以下分析一下CCScrollView的源代码和一些让人蛋疼的东西。

CCScrollView::CCScrollView()
: m_fZoomScale(0.0f)
, m_fMinZoomScale(0.0f)
, m_fMaxZoomScale(0.0f)
, m_pDelegate(NULL)        //view管理器
, m_eDirection(kCCScrollViewDirectionBoth)  //滚动类型
, m_bDragging(false)
, m_pContainer(NULL)                        //container层
, m_bTouchMoved(false)
, m_bBounceable(false)                      //弹性开关
, m_bClippingToBounds(false)                //弹性开关
, m_fTouchLength(0.0f)
, m_pTouches(NULL)
, m_fMinScale(0.0f)
, m_fMaxScale(0.0f)
{

}

CCScrollView* CCScrollView::create(CCSize size, CCNode* container/* = NULL*/)
{
    CCScrollView* pRet = new CCScrollView();
    if (pRet && pRet->initWithViewSize(size, container))
    {
        pRet->autorelease();
    }
    else
    {
        CC_SAFE_DELETE(pRet);
    }
    return pRet;
}

bool CCScrollView::initWithViewSize(CCSize size, CCNode *container/* = NULL*/)
{
    if (CCLayer::init())//scrollview继承CCLayer
    {
        m_pContainer = container;

        if (!this->m_pContainer)
        {
        m_pContainer = CCLayer::create();//create container层
            this->m_pContainer->ignoreAnchorPointForPosition(false);
            this->m_pContainer->setAnchorPoint(ccp(0.0f, 0.0f));
        }

        this->setViewSize(size);//设置视图尺寸，假设使用CCScrollView::create() 引擎会设置 size 为 CCSizeMake(200, 200)


        setTouchEnabled(true); //scrollview 自然是要有触摸的
        m_pTouches = new CCArray();//触点 array
        m_pDelegate = NULL;
        m_bBounceable = true;    //默认弹性开启
        m_bClippingToBounds = true;
        //m_pContainer->setContentSize(CCSizeZero);
        m_eDirection  = kCCScrollViewDirectionBoth;  //默认both滚动模式
        m_pContainer->setPosition(ccp(0.0f, 0.0f));
        m_fTouchLength = 0.0f;

        this->addChild(m_pContainer);
        m_fMinScale = m_fMaxScale = 1.0f;  //默认放缩1.0
        m_mapScriptHandler.clear();  //清理回调列表
        return true;
    }
    return false;
}

我们补习一下滚动模式，CCScrollView中定义了一个枚举类型来表示滚动模式

typedef enum {
    kCCScrollViewDirectionNone = -1,   //不滚动
    kCCScrollViewDirectionHorizontal = 0,  //横向滚动
    kCCScrollViewDirectionVertical,   //竖向滚动
    kCCScrollViewDirectionBoth   //双向滚动
} CCScrollViewDirection;

初始化就先讲到这，在看看属性设置上一些东西

void CCScrollView::setContainer(CCNode * pContainer)
{
    // Make sure that 'm_pContainer' has a non-NULL value since there are
    // lots of logic that use 'm_pContainer'.
    if (NULL == pContainer)
        return;
    this->removeAllChildrenWithCleanup(true);  //这个就是多次使用setContainer却仅仅能显示一个sprite的原因
    this->m_pContainer = pContainer //假设setContentSize在setContainer之前，实际上设置的size给引擎自带的container，而不是目标container
    this->m_pContainer->ignoreAnchorPointForPosition(false);
    this->m_pContainer->setAnchorPoint(ccp(0.0f, 0.0f));
    this->addChild(this->m_pContainer);
    this->setViewSize(this->m_tViewSize);
}

void CCScrollView::setViewSize(CCSize size)
{
    m_tViewSize = size;
    CCLayer::setContentSize(size); //这里不是container的size。而是scrollview的size
}

void CCScrollView::setContentSize(const CCSize & size)
{
    if (this->getContainer() != NULL)
    {
        this->getContainer()->setContentSize(size); //这里才是设置container的size
        this->updateInset();                        //设置弹性状态下虚拟边界值。
    }
}

/**尽管setcontainer仅仅能用一次。可是addchild却能够满足我们的愿望。
 * make sure all children go to the container
 */
void CCScrollView::addChild(CCNode * child, int zOrder, int tag)
{
    child->ignoreAnchorPointForPosition(false);
    child->setAnchorPoint(ccp(0.0f, 0.0f));
    if (m_pContainer != child) {
        m_pContainer->addChild(child, zOrder, tag);
    } else {
        CCLayer::addChild(child, zOrder, tag);
    }
}

属性设置完了，显示是没问题了。只是scrollview究竟是怎样滚动的？

首先：

virtual bool ccTouchBegan(CCTouch *pTouch, CCEvent *pEvent);
    virtual void ccTouchMoved(CCTouch *pTouch, CCEvent *pEvent);
    virtual void ccTouchEnded(CCTouch *pTouch, CCEvent *pEvent);

代码太多，这里就不全贴出来了。有兴趣能够自己去看源代码。让我们把主要代码摘出来

void CCScrollView::setContentOffset(CCPoint offset, bool animated/* = false*/) //此方法在ccTouchMoved中调用，功能是将container移动到指定位置
{
    if (animated)
    { //animate scrolling
        this->setContentOffsetInDuration(offset, BOUNCE_DURATION);//将container移动到指定位置，BOUNCE_DURATION=0.15f。移动时间
    } 
    else
    { //set the container position directly
        if (!m_bBounceable)             //未开启边界弹性
        {
            const CCPoint minOffset = this->minContainerOffset();
            const CCPoint maxOffset = this->maxContainerOffset();

            offset.x = MAX(minOffset.x, MIN(maxOffset.x, offset.x));
            offset.y = MAX(minOffset.y, MIN(maxOffset.y, offset.y));
        }


        m_pContainer->setPosition(offset);


        if (m_pDelegate != NULL)
        {
            m_pDelegate->scrollViewDidScroll(this);   //回调虚函数，由子类override。lua中能够注冊该函数的回调
        }
    }
}

void CCScrollView::setContentOffsetInDuration(CCPoint offset, float dt) //好了，动画来了。
{
    CCFiniteTimeAction *scroll, *expire;
    scroll = CCMoveTo::create(dt, offset);
    expire = CCCallFuncN::create(this, callfuncN_selector(CCScrollView::stoppedAnimatedScroll));
    m_pContainer->runAction(CCSequence::create(scroll, expire, NULL));
    this->schedule(schedule_selector(CCScrollView::performedAnimatedScroll));  
}

void CCScrollView::deaccelerateScrolling(float dt) //该方法是在ccTouchEnded中的主要内容 ，当滑动停止的时候，container还会移动一段距离。
    if (m_bDragging) //拖拽的话该方法不会多次循环调用
    {
        this->unschedule(schedule_selector(CCScrollView::deaccelerateScrolling));
        return;
    }
    float newX, newY;
    CCPoint maxInset, minInset;

    m_pContainer->setPosition(ccpAdd(m_pContainer->getPosition(), m_tScrollDistance));

    if (m_bBounceable)            //弹性设置边界，该值>设置containerSize值。
    {
        maxInset = m_fMaxInset;
        minInset = m_fMinInset;
    }
    else
    {
        maxInset = this->maxContainerOffset();
        minInset = this->minContainerOffset();
    }

    //check to see if offset lies within the inset bounds
    newX     = MIN(m_pContainer->getPosition().x, maxInset.x);
    newX     = MAX(newX, minInset.x);
    newY     = MIN(m_pContainer->getPosition().y, maxInset.y);
    newY     = MAX(newY, minInset.y);

    newX = m_pContainer->getPosition().x;
    newY = m_pContainer->getPosition().y;

    m_tScrollDistance     = ccpSub(m_tScrollDistance, ccp(newX - m_pContainer->getPosition().x, newY - m_pContainer->getPosition().y));
    m_tScrollDistance     = ccpMult(m_tScrollDistance, SCROLL_DEACCEL_RATE);
    this->setContentOffset(ccp(newX,newY));
    //滑动灵敏度推断，边界推断，结束定时任务。在每次移动结束都会调用
    if ((fabsf(m_tScrollDistance.x) <= SCROLL_DEACCEL_DIST &&
         fabsf(m_tScrollDistance.y) <= SCROLL_DEACCEL_DIST) ||
        newY > maxInset.y || newY < minInset.y ||
        newX > maxInset.x || newX < minInset.x ||
        newX == maxInset.x || newX == minInset.x ||
        newY == maxInset.y || newY == minInset.y)
    {
        this->unschedule(schedule_selector(CCScrollView::deaccelerateScrolling));
        this->relocateContainer(true); //又一次设置locate。边界弹性
    }
}

void CCScrollView::relocateContainer(bool animated)  //没什么好说的，推断边界。如超出的话就移动回来
{
    CCPoint oldPoint, min, max;
    float newX, newY;

    min = this->minContainerOffset();
    max = this->maxContainerOffset();

    oldPoint = m_pContainer->getPosition();


    newX     = oldPoint.x;
    newY     = oldPoint.y;
    if (m_eDirection == kCCScrollViewDirectionBoth || m_eDirection == kCCScrollViewDirectionHorizontal)
    {
        newX     = MAX(newX, min.x);
        newX     = MIN(newX, max.x);
    }


    if (m_eDirection == kCCScrollViewDirectionBoth || m_eDirection == kCCScrollViewDirectionVertical)
    {
        newY     = MIN(newY, max.y);
        newY     = MAX(newY, min.y);
    }


    if (newY != oldPoint.y || newX != oldPoint.x)
    {
       this->setContentOffset(ccp(newX, newY), animated);
    }
}