[application（_ application：UIApplication，didFinishLaunchingWithOptions）在启动时未调用

Question

免责声明：我是iOS应用开发的新手。

我的目标是如果firebase auth告诉我该用户尚未登录，并且如果他已登录，我希望将其发送到登录屏幕，我想将其发送到主屏幕。我在MainViewController（也链接到仅具有应用程序徽标的情节提要）中进行路由。当我通过在模拟器中的多应用程序UI中向上滑动杀死应用程序并重新启动它时，不会调用application (didFinishLaunchingWithOptions)方法，并且每次都会显示登录屏幕。我不明白发生了什么，如果再次启动应用程序时甚至没有调用该方法，这真的无法达到检查用户是否从firebase登录的目的，将不胜感激！ （这与我所看到的SceneDelegate方法有关吗，据我了解，无论启动应用程序时，都应调用didFinishLaunching方法）

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.

        print("---------appDelegate didFinishLaunchingWithOptions called!---------------")
        window = UIWindow(frame: UIScreen.main.bounds)
        window?.makeKeyAndVisible()
        window?.rootViewController = MainViewController()
        FirebaseApp.configure()
        return true
    } 

这里是所请求的MainViewController的代码

import UIKit
import Firebase

class MainViewController: UIViewController {

    var handle: AuthStateDidChangeListenerHandle?

    override func viewDidLoad() {
        super.viewDidLoad()
        DispatchQueue.main.async {
            self.handle = Auth.auth().addStateDidChangeListener { (auth, user) in
                if user == nil {
                    print("nil user -----------")
                    self.perform(#selector(self.showHomeController), with: nil, afterDelay: 3)
              } else {
                    print("non nil user --------")
                    self.perform(#selector(self.showWelcomeController), with: nil, afterDelay: 3)
              }
            }
        }
    }

    @objc func showWelcomeController () {
        present(WelcomeViewController(), animated: true, completion: nil)
    }

    @objc func showHomeController () {
        present(HomeViewController(), animated: true, completion: nil)
    }


}

[------------ appDelegate didFinishLaunchingWithOptions称为！---------------当在模拟器中构建并打开项目时，仅打印一次

Answer 1