import UIKit
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
//设置window大小，UIScreen.main.bounds获取屏幕大小
self.window = UIWindow(frame: UIScreen.main.bounds)
//设置背景颜色
self.window?.backgroundColor = #colorLiteral(red: 0.4745098054, green: 0.8392156959, blue: 0.9764705896, alpha: 1)
//设置window成为主屏幕，并显示
self.window?.makeKeyAndVisible()
//创建根控制器
self.window?.rootViewController = UIViewController()
//设置子视图（红色）
//创建子视图（视图位置，视图大小）
let redView = UIView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
//视图背景颜色
redView.backgroundColor = UIColor.red
//视图tag值（视图唯一标识）
redView.tag = 201
//设置视图中心点
redView.center = (window?.center)!
//将视图切成圆形（半径）
redView.layer.cornerRadius = 100
//将视图添加到主屏幕
self.window?.addSubview(redView)
//黄色（下同）
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)!
self.window?.addSubview(yellowView)
//蓝色（下同）
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
self.window?.addSubview(blueView)
//定时器：参数1:定时执行的间隔，参数2:执行目标，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: 1, target: self, selector: #selector(chengeColor), userInfo: nil, repeats: true)
return true
}
//定时器方法
func chengeColor(){
//
let redView = self.window?.viewWithTag(201)
//存储颜色
let color = redView?.backgroundColor
//交换颜色
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:.
}
}