如何显示 SwiftUI 视图而不是 UIViewController？

Question

Total X-code newbie here so pls forgive the incorrect terminology.

In a tutorial, I'm trying to replace a "screen" with a new SwiftUI screen that I've added to the tutorial.

Below is the full code of AppController which calls the screens. In the block marked with the X's, you will see that I've commented out rootViewController = LoginViewController() to replace it with rootViewController = WelcomeView() .

LoginViewController starts like this:

import UIKit
import FirebaseAuth

final class LoginViewController: UIViewController {
...

Whereas WelcomeView starts like this:

import SwiftUI

struct WelcomeView: View {
...

So obviously, my problem is lies in the differences between the old ways and the new SwiftUI, but I'm lost as to how to "call" a "screen" that is SwiftUI in the same way that you do a UIViewController type?

The error message on my line is "Cannot assign value of type 'WelcomeView' to type 'UIViewController?'"

import UIKit
import Firebase


final class AppController {
  static let shared = AppController()
  // swiftlint:disable:next implicitly_unwrapped_optional
  private var window: UIWindow!
  private var rootViewController: UIViewController? {
    didSet {
      window.rootViewController = rootViewController
    }
  }

  init() {
    NotificationCenter.default.addObserver(
      self,
      selector: #selector(handleAppState),
      name: .AuthStateDidChange,
      object: nil)
  }

  // MARK: - Helpers
  func configureFirebase() {
    FirebaseApp.configure()
  }

  func show(in window: UIWindow?) {
    guard let window = window else {
      fatalError("Cannot layout app with a nil window.")
    }

    self.window = window
    window.tintColor = .primary
    window.backgroundColor = .white

    handleAppState()

    window.makeKeyAndVisible()
  }
  
  
  


  
  

  //xxxxxxxxxxxxxxx - this is where my problem is - xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
  @objc private func handleAppState() {
    if let user = Auth.auth().currentUser {
      let channelsViewController = ChannelsViewController(currentUser: user)
      rootViewController = NavigationController(channelsViewController)
    } else {
      //rootViewController = LoginViewController()
      rootViewController = WelcomeView()
  //xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx          


      

      
      
      
    }
  }
  
  

  
  
}

Answer 1

There is UIHostingController for such purpose, so you need to inject your view, like

rootViewController = UIHostingController(rootView: WelcomeView())