霓虹灯

import UIKit

@UIApplicationMain

class AppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?

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

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

self.window?.backgroundColor=#colorLiteral(red: 0.721568644, green: 0.8862745166, blue: 0.5921568871, alpha: 1)

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

blueView.tag=202

self.window?.addSubview(blueView)

blueView.layer.cornerRadius=50

let purpleView=UIView(frame: CGRect(x: 182, y: 343, width: 50, height: 50))

purpleView.backgroundColor=UIColor.purple

purpleView.tag=203

self.window?.addSubview(purpleView)

purpleView.layer.cornerRadius=25

//参数1:定时器实行的间隔

//参数2:找的目标对象

//参数3:目标对象执行的方法

//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:定时器的目标对象执行的方法

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

self.window?.viewWithTag(202)?.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:.

}

}