今天学习了UI

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

// Override point for customization after application launch.

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

self.window?.backgroundColor = #colorLiteral(red: 0.8549019694, green: 0.250980407, blue: 0.4784313738, alpha: 1)

self.window?.makeKeyAndVisible()

self.window?.rootViewController = UIViewController()

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

redview.backgroundColor = #colorLiteral(red: 0.2588235438, green: 0.7568627596, blue: 0.9686274529, alpha: 1)

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 = #colorLiteral(red: 0.9568627477, green: 0.6588235497, blue: 0.5450980663, alpha: 1)

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 = #colorLiteral(red: 0.3647058904, green: 0.06666667014, blue: 0.9686274529, alpha: 1)

blueview.tag = 202

self.window?.addSubview(blueview)

blueview.layer.cornerRadius = 50

//定时器

//参数一：定时执行的间隔

//参数二：目标对象

//参数三：目标对象选者执行的方法

//参数四：用户信息nil

//参数五：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：定时器找的目标对象的执行方法

func changecolor(){

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

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

}