Navigation controller to view controller that is not initial view controller - swift

Question

Is it possible to add navigation contoller and tab bar to view controller that is not initial view controller?
My “Initial view controller” is Login screen. There’s no need for navigation controller and tab bar.
Navigation controller and tab bar wont appear when i just add them from “Editor -> Embed in -> … “
When Login is successful, then I use this code:
if let viewController = self.storyboard?.instantiateViewController(withIdentifier: "mainView") {
UIApplication.shared.keyWindow?.rootViewController = viewController
self.dismiss(animated: true, completion: nil)
}
I use Xcode 9 and swift 4.
Thank you!

Answer 1

I think you may be looking at this wrong. Always having the login view as the root controller in the view hierarchy, even when not needed would be bad practice. And the LoginController should not own a MainController, but the MainController should own a LoginController. You should make your main view (with the nav controller/tab controller) your root view, and in the viewWillAppear method simply check if the user is authenticated; push the login controller modally if the user is not authenticated. That way your view hierarchy is a bit less complex.
You could have a provider class CurrentUser
class CurrentUser {
var user: User? {
guard let userData = UserDefaults.standard.object(forKey: "user") as? Data,
let user = NSKeyedUnarchiver.unarchiveObject(with: userData) as? User else {
return nil
}
return user
}
static let shared = CurrentUser()
}
And in MainController.viewWillAppear
override func viewWillAppear() {
super.viewWillAppear()
guard let user = CurrentUser.shared.user else {
pushViewController(LoginController(), animated: true)
}
// do additional setup
}
Just my $0.02.

Answer 2

Just to answer your question, not only is it possible but it is common. You can put a navigation controller wherever you want. All that the navigation controller does is create a starting point for the progression of view controllers that are to follow by keeping that history of view controllers alive and in order. Therefore, if you had an app with 3 distinct sections, you may most likely want to put a navigation controller in each section so that the user would be able to drill down into each section independently.