简易霓虹灯做法(Swift语言)

在AppDelegate.swift中输入以下语句：

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 = UIColor.white

self.window?.makeKeyAndVisible()

self.window?.rootViewController = UIViewController()

//redView

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

//yellowView

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

//blueView

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

//添加定时器

//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: 0.8, target: self, selector: #selector(changeColor), userInfo: nil, repeats: true)

return true

}

//MARK:定时器找到目标对象执行的方法

func changeColor() {

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

//存储redView的背景颜色

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

}