Swift storyboard login order - ios

Question

I am relatively new to Swift and I don't have much experience with the events and functions. After investigating a little I started working on a login screen on an existing app that didn't have it before. Here's what I decided to do.
My flow goes in this order:
Login screen
After successful login I save the session info
After login screen I show the main screen using a segue
If I close and reopen the app, my login screen is still the start screen, but inside viewDidAppear I have a session check and if the session exists I perform the segue to show the main controller.
I've seen that users do this the other way around - showing the main screen first and if there's no login session they cover it with the login screen or basically show the login screen first.
In my way of doing this, what I don't like is that the login screen always appears, although to be honest it does the job for this app in specific.
Is there a way to do this without the login screen appearing when there's a session? How is this ideally done in terms of order: login screen first or login screen second? And also, what is better to use, a navigation controller for the changes or segues are enough?

Answer 1

many here say is not recomended doing this way but i'll use appDelegate for this, in didFinishLaunchingWithOptions
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
if requestManager.instance.token != nil {
if requestManager.instance.user.birthDate != nil && requestManager.instance.user.iscomplete() {
print("GOING TO TABBARVC")
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let initialViewController = storyboard.instantiateViewController(withIdentifier: "TabBarVC")
self.window?.rootViewController = initialViewController
self.window?.makeKeyAndVisible()
}else if requestManager.instance.user.birthDate != nil && !requestManager.instance.user.iscomplete(){
print("GOING TO DATANC")
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let initialViewController = storyboard.instantiateViewController(withIdentifier: "TabBarVC")
self.window?.rootViewController = initialViewController
self.window?.makeKeyAndVisible()
}else{
print("GOING TO REGISTER")
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let initialViewController = storyboard.instantiateViewController(withIdentifier: "register")
//loginRequest.instance.delegate = initialViewController as profileViewController
self.window?.rootViewController = initialViewController
self.window?.makeKeyAndVisible()
}
}
so what i check here is for token saved in userdefault. could be checked from keycahin is it's critical, and depeding on what is found may show one or another screen, the last case is just in case where no data at all going to register or login screen.
so you could check for session is there is a session amke window show the main screen no session go to login screen
just like this in code:
if sesion != nil {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let initialViewController = storyboard.instantiateViewController(withIdentifier: "MainVC")
self.window?.rootViewController = initialViewController
self.window?.makeKeyAndVisible()
}else{
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let initialViewController = storyboard.instantiateViewController(withIdentifier: "loginVC")
self.window?.rootViewController = initialViewController
self.window?.makeKeyAndVisible()
}
where MainVC is te id in the storyBoard for the mainViewcontroller and loginVC is the storyboard Idetntifier for loginViewController.