cocos2d-x基本知识点：事件处理机制之触屏事件1

触屏事件：

CCStandardTouchDelegate协议是标准的获得多点触摸的范例，CCTargetedTouchDelegate不用处理触摸点的集合，它是返回单点的。但请注意：CCTargetedTouchDelegate并没有屏蔽多点触摸，而是将多点离散成了单点，同时传递过来了。可以在开始触摸的函数中返回true来实现之后获得的触摸点肯定是自己的。此外，在布景层类CCLayer中可以重写ccTouchesBegan等函数获得触屏信息。

触摸点CCTouch

一般把触摸点的信息放入触点类CCTouch中

locationInView(返回类型->坐标点) ：获得点在画布中的位置

previousLocationInView(返回类型->坐标点)：之前在画布中的位置

setTouchInfo(返回->空)：设置信息，三个参数为ID号、x坐标、y坐标

getID(返回->整形)：获得ID号

获得坐标值：

CCPoint point = touch->locationInView();

point = CCDirector->sharedDirector()->convertToGL(point);

单/多点触摸函数：

ccTargetedTouchDelegate将触摸点分发给各个接收的函数，使用ccTouchBegan，并在返回时返回true，可以让这个触点属于

这个函数的所属对象，并且其他对象不再接收该触点，之后再获得的触摸点肯定是它自己的，这样就省去了对多点触摸时的判断

手指移除屏幕或者目标对象的范围不会触发ccTouchCanceled,这种情况下调用的依然是ccTouchEnded函数。事实上，系统中

断通知需要取消触摸时间的时候会调用ccTouchCancelled,这个中断被调用往往是因为如下几种情况：

1）应用程序长时间没有响应或者当前视图从系统的顶层上移除

2）程序进入后台时，有可能是来电中断、电量低中断和部分机型上的home键被按下

3）屏幕关闭和触摸的时候，某种原因导致距离传感器工作，例如脸靠近

4）部分触摸权限覆盖了本应用的触摸权限

加入单点触摸：

void TouchesPerformTest1::onEnter(){

TouchesMainScene::onEnter();

setTouchEnabled(true);

}

std::string TouchesPerformTest1::title(){

return "Targeted touches";

}

void TouchesPerformTest1::registerWithTouchDispatcher(){

CCDirector* pDirector = CCDirector::sharedDirector();

pDirector->getTouchDispatcher()->addTargetDelegate(this,0,true);

}

bool TouchesPerformTest1::ccTouchBegan(CCTouch* touch,CCEvent* event){

numberOfTouchesB++;

return true;

}

void TouchesPerformTest1::ccTouchMoved(CCTouch* touch,CCEvent* event){

numberOfTouchesM++;

}

void TouchesPerformTest1::ccTouchEnded(CCTouch* touch,CCEvent* event){

numberOfTouchesE++;

}

void TouchesPerformTest1::ccTouchCancelled(CCTouch* touch,CCEvent* event){

numberOfTouchesC++;

}

/*   addTargetedDelegate函数的第一个参数是加入代理的对象，第二个参数是触摸的优先级。触摸的优先级决定了触摸的分发顺序，触摸分发只和布景层的触摸优先级有关，和布景层的渲染顺序(zOrder)完全没关系。最后一个参数代表是否“吞噬”所有的触摸点，如果在本布景层吞噬掉相应的触摸点，那么比它权限低 的以及CCStandardTouchDelegate标准触摸代理无论是多高的权限全都收不到触摸分发 */

如果非布景层和其子类想要使用触摸，那么继承相应代理即可：

class Paddle : public CCSprite,public CCTargetedTouchDelegate{

PaddleState m_state;

public:

paddle(void);

virtual ~Paddle(void);

CCRect rect();

bool initWithTexture(CCTexture2D* aTexture);

virtual void onEnter();

virtual void onExit();

bool containsTouchLocation(CCTouch* touch);

virtual bool ccTouchBegan(CCTouch* touch,CCEvent* event);

virtual void ccTouchMoved(CCTouch* touch,CCEvent* event);

virtual void ccTouchEnded(CCTouch* touch,CCEvent* event);

virtual CCObject* copyWithZone(CCZone* pZone);

vritual void touchDelegateRetain();

virtual void touchDelegateRelease();

static Paddle* paddleWithTexture(CCTexture2D* aTexture);

};

与布景层CCLayer不同的是，这里需要在onEnter和onExit中注册/注销触摸的代理：

void Paddle::onEnter(){

CCDirector* pDirector = CCDirector::sharedDirector();

pDirector->getTouchDispatcher()->addTargetedDelegate(this,0,true);

CCSprite::onEnter();

}

void Paddle::onExit(){

CCDirector* pDirector = CCDirector::sharedDirector();

pDirector->getTouchDispatcher()->removeDelegate(this);

CCSprite::onExit();

}

加入多点触摸：

void TouchesPerformTest2::onEnter(){

TouchesMainScene::onEnter();

setTouchEnabled(true);

}

std::string TouchesPerformTest2::title(){

return "Standard touches";

}

void TouchesPerformeTest2::registerWithTouchDispatcher(){

CCDirector* pDirector = CCDirector::sharedDirector();

pDirector->getTouchDispatcher()->addStandardDelegate(this,0);

}

void TouchesPerformTest2::ccTouchesBegan(CCSet*touches,CCEvent* event){

numberOfTouchesB += touches->count();

}

void TouchesPerformTest2::ccTouchesMoved(CCSet* touches,CCEvent* event){

numberOfTouchesM += touches->count();

}

void TouchesPerformTest2::ccTouchesEnded(CCSet* touches,CCEvent* event){

numberOfTouchesE += touches->count();

}

void TouchesPerformTest2::ccTouchesCancelled(CCSet* touches,CCEvent* event){

numberOfTouchesC += touches->count();

}

多点触摸的实现步骤和单点触摸类似，只是需要从CCSet里获得触点类CCTouch：

void MutiTouchTestLayer::ccTouchesBegan(CCSet *pTouches, CCEvent *pEvent)
{
    CCSetIterator iter = pTouches->begin();
    for (; iter != pTouches->end(); iter++){
        CCTouch* pTouch = (CCTouch*)(*iter);
        TouchPoint* pTouchPoint = TouchPoint::touchPointWithParent(this);
        CCPoint location = pTouch->getLocation();
        pTouchPoint->setTouchPos(location);
        pTouchPoint->setTouchColor(s_TouchColors[pTouch->getID()]);
        addChild(pTouchPoint);
        s_dic.setObject(pTouchPoint, pTouch->getID());

    }

}

源相关代码：

class TouchPoint : public CCNode
{
public:
    TouchPoint()
    {
        setShaderProgram(CCShaderCache::sharedShaderCache()->programForKey(kCCShader_PositionTextureColor));
    }
    virtual void draw()
    {
        ccDrawColor4B(m_TouchColor.r, m_TouchColor.g, m_TouchColor.b, 255);
        glLineWidth(10);
        ccDrawLine( ccp(0, m_pTouchPoint.y), ccp(getContentSize().width, m_pTouchPoint.y) );
        ccDrawLine( ccp(m_pTouchPoint.x, 0), ccp(m_pTouchPoint.x, getContentSize().height) );
        glLineWidth(1);
        ccPointSize(30);
        ccDrawPoint(m_pTouchPoint);
    }
    void setTouchPos(const CCPoint& pt)
    {
        m_pTouchPoint = pt;
    }
    void setTouchColor(ccColor3B color)
    {
        m_TouchColor = color;
    }
    static TouchPoint* touchPointWithParent(CCNode* pParent)
    {
        TouchPoint* pRet = new TouchPoint();
        pRet->setContentSize(pParent->getContentSize());
        pRet->setAnchorPoint(ccp(0.0f, 0.0f));
        pRet->autorelease();
        return pRet;
    }
private:
    CCPoint m_pTouchPoint;
    ccColor3B m_TouchColor;
};
bool MutiTouchTestLayer::init()
{
    if (CCLayer::init())
    {
        setTouchEnabled(true);
        return true;
    }
    return false;
}
static CCDictionary s_dic;
void MutiTouchTestLayer::registerWithTouchDispatcher(void)
{
    CCDirector::sharedDirector()->getTouchDispatcher()->addStandardDelegate(this, 0);
}
void MutiTouchTestLayer::ccTouchesBegan(CCSet *pTouches, CCEvent *pEvent)
{
    CCSetIterator iter = pTouches->begin();
    for (; iter != pTouches->end(); iter++)
    {
        CCTouch* pTouch = (CCTouch*)(*iter);
        TouchPoint* pTouchPoint = TouchPoint::touchPointWithParent(this);
        CCPoint location = pTouch->getLocation();
        pTouchPoint->setTouchPos(location);
        pTouchPoint->setTouchColor(s_TouchColors[pTouch->getID()]);
        addChild(pTouchPoint);
        s_dic.setObject(pTouchPoint, pTouch->getID());
    }
}
void MutiTouchTestLayer::ccTouchesMoved(CCSet *pTouches, CCEvent *pEvent)
{
    CCSetIterator iter = pTouches->begin();
    for (; iter != pTouches->end(); iter++)
    {
        CCTouch* pTouch = (CCTouch*)(*iter);
        TouchPoint* pTP = (TouchPoint*)s_dic.objectForKey(pTouch->getID());
        CCPoint location = pTouch->getLocation();
        pTP->setTouchPos(location);
    }
}
void MutiTouchTestLayer::ccTouchesEnded(CCSet *pTouches, CCEvent *pEvent)
{
    CCSetIterator iter = pTouches->begin();
    for (; iter != pTouches->end(); iter++)
    {
        CCTouch* pTouch = (CCTouch*)(*iter);
        TouchPoint* pTP = (TouchPoint*)s_dic.objectForKey(pTouch->getID());
        removeChild(pTP, true);
        s_dic.removeObjectForKey(pTouch->getID());
    }
}
void MutiTouchTestLayer::ccTouchesCancelled(CCSet *pTouches, CCEvent *pEvent)
{
    ccTouchesEnded(pTouches, pEvent);
}
void MutiTouchTestScene::runThisTest()
{
    MutiTouchTestLayer* pLayer = MutiTouchTestLayer::create();
    addChild(pLayer, 0);
    CCDirector::sharedDirector()->replaceScene(this);
}