霓虹灯代码

self.window = UIWindow(frame:UIScreen.main.bounds)

self.window?.backgroundColor = UIColor.white

self.window?.makeKeyAndVisible()

self.window?.rootViewController = UIViewController()

let redView = UIView(frame:CGRect(x: 107, y: 268, width: 200, height: 200))

redView.tag = 200

redView.backgroundColor = UIColor.red

self.window?.addSubview(redView)

redView.layer.cornerRadius = 100

let yellowView = UIView(frame:CGRect(x: 132, y: 293, width: 150, height: 150))

yellowView.tag = 201

yellowView.backgroundColor = UIColor.yellow

self.window?.addSubview(yellowView)

yellowView.layer.cornerRadius = 75

let blueView = UIView(frame:CGRect(x: 157, y: 318, width: 100, height: 100))

blueView.tag = 202

blueView.backgroundColor = UIColor.blue

self.window?.addSubview(blueView)

blueView.layer.cornerRadius = 50

//定时器 参数1：定时执行的间隔

//参数2：目标对象

//参数3：目标对象选择执行的方法

//参数4：用户信息 nil

//参数5：定时器是否重复执行

Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(changValue), userInfo: nil, repeats: true)

return true

}

//mark:定时器目标找的对象执行方法

func changValue(){

let redView = self.window?.viewWithTag(200)

//存储redView背景颜色

let color = redView?.backgroundColor

self.window?.viewWithTag(200)?.backgroundColor = self.window?.viewWithTag(201)?.backgroundColor

self.window?.viewWithTag(201)?.backgroundColor = self.window?.viewWithTag(202)?.backgroundColor

self.window?.viewWithTag(202)?.backgroundColor = color

}