当应用程序第二次启动时显示第二个 ViewController

show the second ViewController when app launch the second time

所以当我第一次启动我的应用程序时,会有一个欢迎 ViewController。我如何设置一个功能,当用户第二次启动应用程序时显示第二个 ViewController。

在您的应用程序的用户默认值中添加一个布尔值,以检查应用程序是否首次启动。基于此布尔值,在您的应用委托 class.

中加载另一个 ViewController
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
     let isFirst = UserDefaults.standard.bool(forKey: “isLaunched”) // edited this after rmaddy's comment 
     var viewControllerWithIdentifier = "SecondViewController"
     if !isFirst {
        UserDefaults.standard.set(true, forKey: “isLaunched”)
        viewControllerWithIdentifier = "FirstViewController"
     }
     let mainStoryboard : UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
     let initialViewController : UIViewController = mainStoryboard.instantiateViewControllerWithIdentifier(viewControllerWithIdentifier) as UIViewController
     self.window = UIWindow(frame: UIScreen.main.bounds)
     self.window?.rootViewController = initialViewController
     self.window?.makeKeyAndVisible()
     return true
}