Swift - 触摸事件

import UIKit
class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    //一个或多个手指触摸视图或窗口触发此方法
    //touches是UITouch的集合，可以检测触摸书鹣的属性，位置。
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        for touch in touches{
            let t = touch
            if t.tapCount == 2
            {
                self.view.backgroundColor = UIColor.black
            }
            else if t.tapCount == 1
            {
                self.view.backgroundColor = UIColor.red
            }
            print("event Begin")
        }
    }
    //一个或多个手指在视图或窗口触发移动事件
    override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
        for touch in touches{
            let t = touch
            print(t.location(in: self.view))
        }
    }
    //结束触摸事件触发此方法
   override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    print("event end")
    }
    //系统发出取消触发此方法，比如来电话
    override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
        print("event cancelled")
    }
}