How to I go to the "login" ViewController if FirebaseAuth is null? - swift

Question

I am really new to Swift and have a really simple setup. There is a login screen and if the user logs in with correct credentials they go to the first VC in a tab bar.
The transition from login to the tab bar view controllers work fine but when I load the app I am not taken to the login screen if currentUser is nil.
Here is my check in the first VC in the tab bar:
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
if Auth.auth().currentUser == nil {
goToLogin()
}
}
And this is the function in the same VC to go to login
func goToLogin() {
let loginViewController = storyboard?.instantiateViewController(identifier: Constants.Storyboard.loginViewController) as? LoginViewController
view.window?.rootViewController = loginViewController
view.window?.makeKeyAndVisible()
}
The storyboard ID for my login VC is "loginViewController" and the Tab bar controller is my initial view controller
Update
My auth check in App Delegate looks like this:
if Auth.auth().currentUser == nil {
// considering the StoryboardID is same as View Controllers name.
self.makeRootVC(storyBoardName: "Main", vcName: Constants.Storyboard.loginViewController)
} else {
self.makeRootVC(storyBoardName: "Main", vcName: Constants.Storyboard.homeTabBarController)
}
But I am getting this error from the "homeTabBarController":
Type 'Constants.Storyboard' has no member 'homeTabBarController'
homeTabBarController is the StoryboardId for my tab bar controller in the Main storyboard. So why is it not being recognized?

Answer 1

You should do this check in didFinishLaunchingWithOptions in AppDelegate not in ViewController. You can use the below function to change your root view controller.
In AppDelegate.swift
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
if Auth.auth().currentUser == nil {
// considering the StoryboardID is same as View Controllers name.
self.makeRootVC(storyBoardName: "Main", vcName: Constants.Storyboard.loginViewController)
} else {
self.makeRootVC(storyBoardName: "Main", vcName: Constants.Storyboard.yourTabBarController)
}
return true
}
func makeRootVC(storyBoardName : String, vcName : String) {
let vc = UIStoryboard(name: storyBoardName, bundle: Bundle.main).instantiateViewController(withIdentifier: vcName)
let nav = UINavigationController(rootViewController: vc)
nav.navigationBar.isHidden = true
self.window?.rootViewController = nav
let options: UIView.AnimationOptions = .transitionCrossDissolve
let duration: TimeInterval = 0.6
UIView.transition(with: self.window!, duration: duration, options: options, animations: {}, completion: nil)
}