Swift UITouch 的使用

touch 允许多点触碰

在viewLoad（）中

self.view.multipleTouchEnabled = true;

/*     override (重写): 方法名、参数、返回值相同。2.子类方法不能缩小父类方法的访问权限 3.子类方法不能抛出比父类方法更多的异常(但子类方法可以不抛出异常)。4.存在于父类和子类之间 5.方法被定义为final不能被重写;     overload （重载）:参数类型、个数、顺序至少有一个不相同;2.不能重载只有返回值不同的方法名 3.存在于父类和子类、同类中     */

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {        for touch :AnyObject in touches {            let t : UITouch  = touch as! UITouch;            //在屏幕上连续拍击两次，背景变为灰色            if (t.tapCount == 2) {                self.view.backgroundColor = UIColor.grayColor();            }else if(t.tapCount == 1){                self.view.backgroundColor = UIColor.brownColor();            }            print("begin");        }    }    override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {        for touch : AnyObject in touches {            let t : UITouch = touch as! UITouch;            print(t.locationInView(self.view));        }    }    override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {       //两点触摸时，计算两点之间的距离，以及角度        if touches.count == 2 {            //获取触摸点            let frist = (touches as NSSet).allObjects[0] as! UITouch;            let second = (touches as NSSet).allObjects[1] as! UITouch;                        //获取触摸点坐标            let fristPoint = frist.locationInView(self.view);            let secondPoint = second.locationInView(self.view);                        //计算两点之间的距离            let distanceX = fristPoint.x - secondPoint.x;            let distanceY = fristPoint.y - secondPoint.y;            let distance = sqrt(distanceX * distanceX + distanceY * distanceY);            print("两点之间的距离：",distance);                        //计算两点间的角度            let height = secondPoint.y - fristPoint.y;            let width = fristPoint.x - secondPoint.x;            let rads = atan(height/width);            let degrees = 180.0 * rads * 3.1415;            print("两点之间的角度：",degrees);                }<pre name="code" class="html">override func touchesCancelled(touches: Set<UITouch>?, withEvent event: UIEvent?) {        print("event cancelled=====================");    }

}