cocos2d-x CCScrollView和CCTableView的使用

在游戏和应用中常常要实现左右滑动展示游戏帮助、以列表显示内容的UI效果，就像android中的Gallery和ListView。

本文通过CCScrollView和CCTableView分别来实现这两个效果，基于cocos2d-x 2.0.4版本号。 

首先来简单了解一下这两个东东。CCScrollView本身是一个CCLayer，而CCTableView是CCScrollView的子类，这是引擎已经帮我们封装好了的，CCTableView能够设置成横向和纵向，用它能够实现类似于Gallery和ListView的效果。 

1. 首先实现游戏帮助界面 

(1) 创建头文件GalleryLayer.h

#ifndef GALLERY_LAYER_H
#define GALLERY_LAYER_H

#include "cocos2d.h"
#include "SimpleAudioEngine.h"
#include "cocos-ext.h"

USING_NS_CC;
USING_NS_CC_EXT;

class GalleryLayer : public cocos2d::CCLayer ,public CCScrollViewDelegate
{
public:
    virtual bool init();  

    void menuCloseCallback(CCObject* pSender);

    CREATE_FUNC(GalleryLayer);

public:
  //scrollview滚动的时候会调用
  void scrollViewDidScroll(CCScrollView* view);
  //scrollview缩放的时候会调用
  void scrollViewDidZoom(CCScrollView* view);

  virtual void onEnter();
  virtual void onExit();

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

private:
  //依据手势滑动的距离和方向滚动图层
   void adjustScrollView(float offset);
   CCScrollView *m_pScrollView;
   CCPoint m_touchPoint;
   int m_nCurPage;
};

#endif

类GalleryLayer继承了CCScrollViewDelegate，实现了它的两个纯虚函数，主要是为了当scrollview滚动和缩放时回调这两函数。这样我们就能够在这两函数中做相关操作了。

(2) 看源文件GalleryLayer.cpp

#include "GalleryLayer.h"
#include "ListViewLayer.h"

using namespace cocos2d;
using namespace cocos2d::extension;

bool GalleryLayer::init()
{
  bool bRet = false;
  do
  {
       CC_BREAK_IF( !CCLayer::init() );

     m_nCurPage = 1;
     CCSize visibleSize = CCDirector::sharedDirector()->getVisibleSize();
     CCPoint origin = CCDirector::sharedDirector()->getVisibleOrigin();

     CCLayer *pLayer = CCLayer::create();
     char helpstr[30] = {0};
     for (int i = 1; i <= 3; ++ i)
     {
       memset(helpstr, 0, sizeof(helpstr));
       sprintf(helpstr,"bg_%02d.png",i);
       CCSprite *pSprite = CCSprite::create(helpstr);
       pSprite->setPosition(ccp(visibleSize.width * (i-0.5f), visibleSize.height / 2));
       pLayer->addChild(pSprite);
     }

     m_pScrollView = CCScrollView::create(CCSizeMake(960, 640), pLayer);
     m_pScrollView->setContentOffset(CCPointZero);
     m_pScrollView->setTouchEnabled(false);
     m_pScrollView->setDelegate(this);
     m_pScrollView->setDirection(kCCScrollViewDirectionHorizontal);
     pLayer->setContentSize(CCSizeMake(960*3, 640));

     this->addChild(m_pScrollView);

     CCSpriteFrameCache *pCache =  CCSpriteFrameCache::sharedSpriteFrameCache();

     pCache->addSpriteFrame(CCSpriteFrame::create("button_normal.png",CCRectMake(0, 0, 64, 64)),"button_normal.png");
     pCache->addSpriteFrame(CCSpriteFrame::create("button_selected.png",CCRectMake(0, 0, 64, 64)),"button_selected.png");
     for (int i = 1; i <= 3; ++ i)
     {
       CCSprite *pPoint = CCSprite::createWithSpriteFrameName("button_normal.png");
       pPoint->setTag(i);
       pPoint->setPosition(ccp( origin.x + (visibleSize.width - 3 * pPoint->getContentSize().width)/2 + pPoint->getContentSize().width * (i-1), origin.y + 30));
       this->addChild(pPoint);
     }
    CCSprite *pPoint = (CCSprite *)this->getChildByTag(1);
    pPoint->setDisplayFrame(pCache->spriteFrameByName("button_selected.png"));

    bRet = true;
  }while(0);

  return bRet;

}

void GalleryLayer::menuCloseCallback(CCObject* pSender)
{

}

void GalleryLayer::scrollViewDidScroll(cocos2d::extension::CCScrollView *view)
{
  CCLOG("scroll");
}

void GalleryLayer::scrollViewDidZoom(cocos2d::extension::CCScrollView *view)
{
  CCLOG("zoom");
}

void GalleryLayer::onEnter()
{
  CCLayer::onEnter();
  CCDirector::sharedDirector()->getTouchDispatcher()->addTargetedDelegate(this, 1, false);
}

void GalleryLayer::onExit()
{
  CCDirector::sharedDirector()->getTouchDispatcher()->removeDelegate(this);
  CCLayer::onExit();
  CCSpriteFrameCache::sharedSpriteFrameCache()->removeUnusedSpriteFrames();
}

bool GalleryLayer::ccTouchBegan(CCTouch *pTouch, CCEvent *pEvent)
{
  m_touchPoint = CCDirector::sharedDirector()->convertToGL(pTouch->getLocationInView());
  return true;
}

void GalleryLayer::ccTouchMoved(CCTouch *pTouch, CCEvent *pEvent)
{

}

void GalleryLayer::ccTouchEnded(CCTouch *pTouch, CCEvent *pEvent)
{
  CCPoint endPoint = CCDirector::sharedDirector()->convertToGL(pTouch->getLocationInView());
  float distance = endPoint.x - m_touchPoint.x;
  if(fabs(distance) > 50)
  {
    adjustScrollView(distance);
  }
}

void GalleryLayer::ccTouchCancelled(cocos2d::CCTouch *pTouch, cocos2d::CCEvent *pEvent)
{
  CCPoint endPoint = CCDirector::sharedDirector()->convertToGL(pTouch->getLocationInView());
  float distance = endPoint.x - m_touchPoint.x;
  if(fabs(distance) > 50)
  {
    adjustScrollView(distance);
  }
}

void GalleryLayer::adjustScrollView(float offset)
{
  CCSize visibleSize = CCDirector::sharedDirector()->getVisibleSize();
  CCPoint origin = CCDirector::sharedDirector()->getVisibleOrigin();
  CCSpriteFrameCache *pCache =  CCSpriteFrameCache::sharedSpriteFrameCache();
  CCSprite *pPoint = (CCSprite *)this->getChildByTag(m_nCurPage);
  pPoint->setDisplayFrame(pCache->spriteFrameByName("button_normal.png"));
  if (offset<0)
  {
    m_nCurPage ++;
  }else
  {
    m_nCurPage --;
  }

  if (m_nCurPage <1)
  {
    m_nCurPage = 1;
  }

  if(m_nCurPage > 3)
  {
    CCLayer *pLayer = ListViewLayer::create();
    CCScene *pScene = CCScene::create();
    pScene->addChild(pLayer);
    CCDirector::sharedDirector()->replaceScene(pScene);
  }
  else
  {
    pPoint = (CCSprite *)this->getChildByTag(m_nCurPage);
    pPoint->setDisplayFrame(pCache->spriteFrameByName("button_selected.png"));
    CCPoint  adjustPos = ccp(origin.x - visibleSize.width * (m_nCurPage-1), 0);
    m_pScrollView->setContentOffset(adjustPos, true);
  }
}

这里一共同拥有三张图，是从捕鱼达人中拿出来的背景图，当滚完三张图时就跳转到ListViewLayer场景去，上面的代码比較easy懂。 

首先创建一个CCLayer。包括三张背景图。设置CCLayer的ContentSize。并设置三张图片的位置 

然后设置CCLayer为CCScrollview的内容，并设置CCScrollView的显示区域。 

最后依据用户滑动的方向和距离，通过设置scrollview的setContentOffset，滚动视图。 

CCScrollview.h文件里封装了一个枚举类型，一共同拥有四个方向。经常使用横向和纵向，这里使用了横向。

typedef enum {
  kCCScrollViewDirectionNone = -1,
    kCCScrollViewDirectionHorizontal = 0,
    kCCScrollViewDirectionVertical,
    kCCScrollViewDirectionBoth
} CCScrollViewDirection;

以下来看看这部分的效果： 

2. 如今来实现列表展示(ListView)的效果 

（1）创建ListViewLayer.h

#ifndef LISTVIEW_LAYER_H
#define LISTVIEW_LAYER_H

#include "cocos2d.h"
#include "cocos-ext.h"

class ListViewLayer : public cocos2d::CCLayer, public cocos2d::extension::CCTableViewDataSource, public cocos2d::extension::CCTableViewDelegate
{
public:
    virtual bool init();  

    virtual void scrollViewDidScroll(cocos2d::extension::CCScrollView* view);

    virtual void scrollViewDidZoom(cocos2d::extension::CCScrollView* view);

  //处理触摸事件，能够计算点击的是哪一个子项
    virtual void tableCellTouched(cocos2d::extension::CCTableView* table, cocos2d::extension::CCTableViewCell* cell);
  //每一项的宽度和高度
    virtual cocos2d::CCSize cellSizeForTable(cocos2d::extension::CCTableView *table);
  //生成列表每一项的内容
    virtual cocos2d::extension::CCTableViewCell* tableCellAtIndex(cocos2d::extension::CCTableView *table, unsigned int idx);
  //一共多少项
    virtual unsigned int numberOfCellsInTableView(cocos2d::extension::CCTableView *table);

    CREATE_FUNC(ListViewLayer);
};

#endif

ListViewLayer继承了CCTableViewDataSource和CCTableViewDelegate。

这两个抽象类封装了几个实用的函数，我们在以下的源代码中将实现它们。

（2）源文件 ListViewLayer.cpp

#include "ListViewLayer.h"

USING_NS_CC;
USING_NS_CC_EXT;

bool ListViewLayer::init()
{
  bool bRet = false;
  do
  {
    CC_BREAK_IF( !CCLayer::init() );

    CCTableView* pTableView = CCTableView::create(this, CCSizeMake(960, 640));
    pTableView->setDirection(kCCScrollViewDirectionVertical);
    pTableView->setPosition(CCPointZero);
    pTableView->setDelegate(this);
    pTableView->setVerticalFillOrder(kCCTableViewFillTopDown);
    this->addChild(pTableView);
    pTableView->reloadData();

    bRet = true;
  }while(0);

  return bRet;
}

void ListViewLayer::tableCellTouched(CCTableView* table, CCTableViewCell* cell)
{
    CCLog("cell touched at index: %i", cell->getIdx());
}

CCSize ListViewLayer::cellSizeForTable(CCTableView *table)
{
    return CCSizeMake(960, 120);
}

CCTableViewCell* ListViewLayer::tableCellAtIndex(CCTableView *table, unsigned int idx)
{
    CCString *pString = CCString::createWithFormat("%d", idx);
    CCTableViewCell *pCell = table->dequeueCell();
    if (!pCell) {
        pCell = new CCTableViewCell();
        pCell->autorelease();
        CCSprite *pSprite = CCSprite::create("listitem.png");
        pSprite->setAnchorPoint(CCPointZero);
    pSprite->setPosition(CCPointZero);
        pCell->addChild(pSprite);

        CCLabelTTF *pLabel = CCLabelTTF::create(pString->getCString(), "Arial", 20.0);
        pLabel->setPosition(CCPointZero);
    pLabel->setAnchorPoint(CCPointZero);
        pLabel->setTag(123);
        pCell->addChild(pLabel);
    }
    else
    {
        CCLabelTTF *pLabel = (CCLabelTTF*)pCell->getChildByTag(123);
        pLabel->setString(pString->getCString());
    }

    return pCell;
}

unsigned int ListViewLayer::numberOfCellsInTableView(CCTableView *table)
{
    return 20;
}

void ListViewLayer::scrollViewDidScroll(CCScrollView *view)
{
}

void ListViewLayer::scrollViewDidZoom(CCScrollView *view)
{
}

首先须要创建CCTableView，设置它的显示区域和显示方向。这里使用了纵向。设置每一个子项的宽度和高度，子项的数量以及每一个子项相应的内容。每一个子项是一个CCTableViewCell。这里进行了优化，复用了子项对象。

以下是效果图：

源代码下载地址： http://download.csdn.net/detail/zhoujianghai/4975604