Swift, Firebase - Present different ViewControllers in AppDelegate if User is Logged-in - swift

Question

I'm using Firebase for my app and I want to present different view controllers in AppDelegate with the code below but I keep getting an error.
import UIKit
import Firebase
import FirebaseAuth
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
window = UIWindow()
if Auth.auth().currentUser != nil {
window?.rootViewController = HomeController()
} else {
window?.rootViewController = LoginController()
}
return true
}
...
This is the error.
libc++abi.dylib: terminating with uncaught exception of type
NSException
(lldb)
How can I fix this problem?

Answer 1

Swift 4.0
You can use this function as like below in AppDelegate.
func configureWindowAndMakeVisible(rootVC: UIViewController) {
if let app = UIApplication.shared.delegate as? AppDelegate, let window = app.window {
window.rootViewController = rootVC
window.makeKeyAndVisible()
}
}
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
if Auth.auth().currentUser != nil {
// Use initialization (i.e HomeController()) only if you had initialize view in Controller
configureWindowAndMakeVisible(rootVC: HomeController())
} else {
configureWindowAndMakeVisible(rootVC: LoginController())
}
return true
}

Answer 2

First of all, you need to know that you need a reference to the already created instance instead of creating a new one. There can be two case
Case 1. If you want to change the initial view controller on the check of if Auth.auth().currentUser == nil or iAuth.auth().currentUser != nil then you can simply write the code in didFinishLaunchingWithOptions in AppDelegate and make sure you must give the identifier in storyboard and use the same identifier in the code
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
let mainView = UIStoryboard(name: "MainStoryboard", bundle: nil)
if Auth.auth().currentUser != nil {
let viewcontroller : MainViewController = mainView.instantiateViewController(withIdentifier: "MainViewIdentifier") as! MainViewController
self.window!.rootViewController = viewcontroller
self.window?.makeKeyAndVisible();
} else {
let viewcontroller : LoginViewController = mainView.instantiateViewController(withIdentifier: "loginViewIdentifier") as! LoginViewController
self.window!.rootViewController = viewcontroller
self.window?.makeKeyAndVisible();
}
return true
}
Case 2. Suppose you have Main/Home/Dash VC (View controller) and it’s always is the initial view controller then there you have implemented the check if Auth.auth().currentUser == nil then present/push the Login view controller else not.

Answer 3

You are Direct Creating New Instance of ViewController
Try the following code
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
if Auth.auth().currentUser != nil {
var mainView: UIStoryboard!
mainView = UIStoryboard(name: "MainStoryboard", bundle: nil)
let viewcontroller : HomeController = mainView.instantiateViewController(withIdentifier: "someViewController") as! HomeController
self.window!.rootViewController = viewcontroller
self.window?.makeKeyAndVisible();
} else {
var mainView: UIStoryboard!
mainView = UIStoryboard(name: "MainStoryboard", bundle: nil)
let viewcontroller : LoginController = mainView.instantiateViewController(withIdentifier: "loginVCIdentifier") as! LoginController
self.window!.rootViewController = viewcontroller
self.window?.makeKeyAndVisible();
}
return true
}
Make Sure you have given identifier to controller from storyboard