swift 视图控件的应用:霓虹灯

import UIKit


class AppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?

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: 0.4745098054, green: 0.8392156959, blue: 0.9764705896, alpha: 1)




self.window?.rootViewController = UIViewController()



let redView = UIView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))


redView.backgroundColor = UIColor.red


redView.tag = 201


redView.center = (window?.center)!


redView.layer.cornerRadius = 100




let yellowView = UIView(frame: CGRect(x: 0, y: 0, width: 150, height: 150))

yellowView.backgroundColor = UIColor.yellow

yellowView.tag = 202

yellowView.center = (window?.center)!

yellowView.layer.cornerRadius = 75

yellowView.center = (window?.center)!



let blueView = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))

blueView.backgroundColor = UIColor.blue

blueView.tag = 203

blueView.center = (window?.center)!

blueView.layer.cornerRadius = 50



Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(chengeColor), userInfo: nil, repeats: true)

return true



func chengeColor(){


let redView = self.window?.viewWithTag(201)


let color = redView?.backgroundColor


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

self.window?.viewWithTag(202)?.backgroundColor = self.window?.viewWithTag(203)?.backgroundColor

self.window?.viewWithTag(203)?.backgroundColor = color


func applicationWillResignActive(_ application: UIApplication) {

// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.

// Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.


func applicationDidEnterBackground(_ application: UIApplication) {

// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.

// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.


func applicationWillEnterForeground(_ application: UIApplication) {

// Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.


func applicationDidBecomeActive(_ application: UIApplication) {

// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.


func applicationWillTerminate(_ application: UIApplication) {

// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.