首先，来看下代码：
声明文件：
#ifndef __loading__MoreTouches__
#define __loading__MoreTouches__ #include <iostream>
#include "cocos2d.h"
USING_NS_CC;
class MoreTouches :public CCLayer
{
public:
bool init();
//virtual void registerWithTouchDispather(void); //由于是继承自CCLayer，这个方法就不用重写了,但下面几个方法还是要重写滴
virtual void ccTouchesCancellnd(CCSet *pTouches,CCEvent *pEvent);
virtual void ccTouchesBegan(CCSet *pTouches,CCEvent *pEvent);//注意这个方法和单点触控方法的返回类型不同
virtual void ccTouchesEnded(CCSet *pTouches,CCEvent *pEvent);
virtual void ccTouchesMoved(CCSet *pTouches,CCEvent *pEvent);
static CCScene *scene();
virtual void onEnter();
virtual void onExit();
CREATE_FUNC(MoreTouches); public:
double distance; //两个触摸点之间的距离
double deltax; //目标x轴的改变值
double deltay; //目标y轴的改变值
CCSprite *bg; //目标精灵
double mscale; //初始地图缩放比例 }; #endif /* defined(__loading__MoreTouches__) */
定义文件：
#include "MoreTouches.h" bool MoreTouches::init()
{
if(!CCLayer::init())
{
return false;
}
bg=CCSprite::create("fullbg.png"); //初始化目标图片
this->addChild(bg); mscale=1.0; //初始化图片的缩放比例
return true;
} //void MoreTouches::registerWithTouchDispather()
//{
// CCDirector::sharedDirector()->getTouchDispatcher()->addStandardDelegate(this, 0);
//} void MoreTouches::ccTouchesBegan(cocos2d::CCSet *pTouches, cocos2d::CCEvent *pEvent)
{
if(pTouches->count()>=2) //如果触摸点不少于两个
{
CCSetIterator iter=pTouches->begin();
CCPoint mPoint1=((CCTouch *)(*iter))->getLocationInView();
mPoint1 = CCDirector::sharedDirector()->convertToGL(mPoint1);
iter++;
CCPoint mPoint2=((CCTouch *)(*iter))->getLocationInView();
mPoint2 = CCDirector::sharedDirector()->convertToGL(mPoint2); distance=sqrt((mPoint2.x-mPoint1.x)*(mPoint2.x-mPoint1.x)+(mPoint2.y-mPoint1.y)*(mPoint2.y-mPoint1.y));//计算两个触摸点距离
deltax = (mPoint1.x + mPoint2.x)/2 - bg->getPositionX(); //得到两个触摸点中点和精灵锚点的差值
deltay = (mPoint1.y + mPoint2.y)/2 - bg->getPositionY();
CCLog("ccTouchesBegan ..."); }
}
void MoreTouches::ccTouchesMoved(cocos2d::CCSet *pTouches, cocos2d::CCEvent *pEvent)
{
if(pTouches->count()>=2) //如果移动时触摸点的个数不少于两个
{
CCSetIterator iter = pTouches->begin();
CCPoint mPoint1 = ((CCTouch*)(*iter))->getLocationInView();
mPoint1 = CCDirector::sharedDirector()->convertToGL(mPoint1);
iter++;
CCPoint mPoint2 = ((CCTouch*)(*iter))->getLocationInView();
mPoint2 = CCDirector::sharedDirector()->convertToGL(mPoint2); //获得新触摸点两点之间的距离
double mdistance = sqrt((mPoint1.x-mPoint2.x)*(mPoint1.x-mPoint2.x)+(mPoint1.y-mPoint2.y)*(mPoint1.y-mPoint2.y));
mscale = mdistance/distance * mscale; // 新的距离 / 老的距离 * 原来的缩放比例，即为新的缩放比例
distance = mdistance;
bg->setScale(mscale); double x = (mPoint2.x+mPoint1.x)/2 - deltax; //计算两触点中点与精灵锚点的差值
double y = (mPoint2.y+mPoint1.y)/2 - deltay;
bg->setPosition(ccp(x,y)); //保持两触点中点与精灵锚点的差值不变
deltax = (mPoint1.x+ mPoint2.x)/2 - bg->getPositionX(); //计算新的偏移量
deltay = (mPoint2.y + mPoint1.y)/2 - bg->getPositionY();
CCLog("ccTouchMoved ....");
}
if(pTouches->count()==1) //如果触摸点为一个
{
CCSetIterator iter = pTouches->begin();
CCPoint mPoint=((CCTouch*)(*iter))->getLocationInView();
mPoint=CCDirector::sharedDirector()->convertToGL(mPoint); //坐标转换
bg->setPosition(mPoint); //直接移动精灵
}
}
void MoreTouches::ccTouchesEnded(cocos2d::CCSet *pTouches, cocos2d::CCEvent *pEvent)
{ }
void MoreTouches::ccTouchesCancellnd(cocos2d::CCSet *pTouches, cocos2d::CCEvent *pEvent)
{ }
CCScene *MoreTouches::scene()
{
CCScene *scene=CCScene::create();
MoreTouches *layer=MoreTouches::create();
scene->addChild(layer);
return scene;
}
void MoreTouches::onEnter()
{
CCLayer::onEnter();
setTouchEnabled(true);CCLog("onenter");
}
void MoreTouches::onExit()
{
CCLayer::onExit();
CCDirector::sharedDirector()->getTouchDispatcher()->removeDelegate(this); //移除触摸代理
}
首先要实现缩放这个逻辑，在ccTouchesBegan中检测，如果触摸点的个数大于两个，那么取前两个点，使用两点距离公式计算两点距离，在ccTouchesMoved中检测，如果触摸点的个数大于两个，那么继续计算这两个点的距离，然后通过距离，计算得到缩放比例，调用setScale设置缩放比例即可。
另外，除了缩放处理外，还需要处理位置问题，在ccTouchesBegan中计算两个触点的中点位置和精灵锚点的差，在ccTouchesMoved中，随着缩放，保持两触点中点和精灵锚点的差不变即可，ccTouchesEnded和ccTouchesCancelled中不需要修改。
接下来，就重点说下在实现时遇到的问题吧，主要就一个，就是当在ios模拟器中操作时，我按着option键，可以出现两个点，但程序中始终只能得到一个点，即count=1，
移动时也根本不能实现缩放。后来，终于谷歌出结果了，原来需要修改ios目录下的 AppController.mm文件
static AppDelegate s_sharedApplication;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
// Add the view controller's view to the window and display.
window = [[UIWindow alloc] initWithFrame: [[UIScreen mainScreen] bounds]];
EAGLView *__glView = [EAGLView viewWithFrame: [window bounds]
pixelFormat: kEAGLColorFormatRGBA8
depthFormat: GL_DEPTH_COMPONENT16
preserveBackbuffer: NO
sharegroup: nil
multiSampling: NO
numberOfSamples:0 ]; // Use RootViewController manage EAGLView
viewController = [[RootViewController alloc] initWithNibName:nil bundle:nil];
viewController.wantsFullScreenLayout = YES;
viewController.view = __glView; // Set RootViewController to window
if ( [[UIDevice currentDevice].systemVersion floatValue] < 6.0)
{
// warning: addSubView doesn't work on iOS6
[window addSubview: viewController.view];
}
else
{
// use this method on ios6
[window setRootViewController:viewController];
}
[window makeKeyAndVisible];
[[UIApplication sharedApplication] setStatusBarHidden: YES];
cocos2d::CCApplication::sharedApplication()->run();
[__glView setMultipleTouchEnabled:YES]; //主要就是这句了
return YES;
}
简单来说，就是： AppController.mm 里要启用多点触摸才可以，在- (BOOL)application:(UIApplication *)application添加[__glView setMultipleTouchEnabled:YES];
这样，当我们按着option键和鼠标时，移动鼠标，就可以实现缩放了，当只用鼠标时，可以实现图片的移动，问题解决。