霓虹灯

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func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

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.backgroundColor = UIColor.red

redView.tag = 200

self.window?.addSubview(redView)

redView.layer.cornerRadius = 100

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

yellowView.backgroundColor = UIColor.yellow

yellowView.tag = 201

self.window?.addSubview(yellowView)

yellowView.layer.cornerRadius = 75

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

blueView.backgroundColor = UIColor.blue

self.window?.addSubview(blueView)

blueView.tag = 202

blueView.layer.cornerRadius = 50

// 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: 0.3, target: self, selector: #selector(changeColor), userInfo: nil, repeats: true)

return true

}

// MARK:- 定制器找的目标对象执行方法

func changeColor() {

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

}