Swift - 触摸事件（点击，移动，抬起等）说明及用例

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import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {

        super.viewDidLoad()

        //支持多点触摸

        self.view.multipleTouchEnabled = true

    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()

    }

    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {

        for touch: AnyObject in touches {

            var t:UITouch = touch as! UITouch

            //当在屏幕上连续拍动两下时，背景恢复为白色

            if(t.tapCount == 2)

            {

                self.view.backgroundColor = UIColor.whiteColor()

            }

                //当在屏幕上单击时，屏幕变为红色

            else if(t.tapCount == 1)

            {

                self.view.backgroundColor = UIColor.redColor()

            }

            println("event begin!")

        }

    }

    override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent)

    {

        for touch: AnyObject in touches {

            var t:UITouch = touch as! UITouch

            println(t.locationInView(self.view))

        }

    }

    override func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent)

    {

        //两点触摸时，计算两点间的距离

        if touches.count == 2{

            //获取触摸点

            let first = (touches as NSSet).allObjects[0] as! UITouch

            let second = (touches as NSSet).allObjects[1] as! UITouch

            //获取触摸点坐标

            let firstPoint = first.locationInView(self.view)

            let secondPoint = second.locationInView(self.view)

            //计算两点间的距离

            let deltaX = secondPoint.x - firstPoint.x

            let deltaY = secondPoint.y - firstPoint.y

            let initialDistance = sqrt(deltaX*deltaX + deltaY*deltaY)

            println("两点间距离：\(initialDistance)")

        }

        println("event end!")

    }

    override func touchesCancelled(touches: Set<NSObject>, withEvent event: UIEvent)

    {

        println("event canceled!")

    }

}