Change the root view of UIHostingController in SwiftUI

Question

For a new SwiftUI iOS app, I do the following in the SceneDelegate

if let windowScene = scene as? UIWindowScene {
    let window =          


        

Answer 1

You can make a Router class

import Foundation
import UIKit
import SwiftUI

class Router {
    
    class var window: UIWindow? {
        if let scene = UIApplication.shared.connectedScenes.first as? UIWindowScene {
            if let sceneDelegate = scene.delegate as? SceneDelegate {
                let window = UIWindow(windowScene: scene)
                sceneDelegate.window = window
                window.makeKeyAndVisible()
                return window
            }
        }
        return nil
    }
    
    static func showMain() {
        window?.rootViewController = UIHostingController(rootView: ContentView())
    }
    
}

Usage :

Router.showMain()

And with this you can decide which window you want as your root at any given time.

Answer 2

Very good answer LuLugaga, updated if you don't want to use @Observablebject so will not keep updating all the time, you can use Subject, as soon as you update token String, RootView will update.

struct RootView: View {

    var loginViewModel: LoginViewModel = LoginViewModel()

    @State var tokenString = ""

    var body: some View {
        Group {
            tokenString.count > 0 ? AnyView(ContentView(model: playerViewModel)) :  AnyView(LoginView(loginViewModel: loginViewModel))
        }.onReceive(loginViewModel.tokenString) {
            self.tokenString = $0
        }
    }
}


class LoginViewModel {

    let tokenString = PassthroughSubject<String, Never>()

    var token: String {
        get { return "" }
    set {
        self.tokenString.send(newValue)
    }
}

Answer 3

let scene = UIApplication.shared.connectedScenes.first as? UIWindowScene

if let windowScenedelegate = scene?.delegate as? SceneDelegate {
   let window = UIWindow(windowScene: scene!)
   window.rootViewController = UIHostingController(rootView:ContentView())
   windowScenedelegate.window = window
   window.makeKeyAndVisible()
}

By using this we can change the rootView in any button click by implementing the above code.

Answer 4

For some animation while changing the rootview use the below code in sceneDelegate:

    window.rootViewController = UIHostingController(rootView: HomeView())

    // A mask of options indicating how you want to perform the animations.
    let options: UIView.AnimationOptions = .transitionCrossDissolve

    // The duration of the transition animation, measured in seconds.
    let duration: TimeInterval = 0.3

    // Creates a transition animation.
    UIView.transition(with: window, duration: duration, options: options, animations: {}, completion:
    { completed in
        // maybe do something on completion here
    })

Answer 5

Declare an AppRootView, something like this:

struct AppRootView: View {

    @ObservedObject private var auth: Auth
    var body: some View {
        Group {
            if auth.token != nil {
                MainTabbedView()
            } else {
                StartRegistrationView()
            }
        }
    }
}

and then in SceneDelegate set it as the root view:

window.rootViewController = UIHostingController(rootView: AppRootView(auth: $auth))

You have to bind your view to your Auth() either by passing it in as I did above or by setting it on your environment. The beauty of SwiftUI is that as soon as the token is not nil, the view will redraw and your user will find them selves in MainTabbedView.