NavigationControllerSwiftUI.swift

// NavigationControllerSwiftUI.swift 
//  Created by Kanishka on 17/11/21.
// More: https://bio.link/kanishka

import SwiftUI
import UIKit

// Reference: https://stackoverflow.com/a/67495147/7992741

struct NavigationController {
    
    
    /// Pops the current view to the root view
  static func popToRootView() {
    findNavigationController(viewController: UIApplication.shared.windows.filter { $0.isKeyWindow }.first?.rootViewController)?
      .popToRootViewController(animated: true)
  }
    
    /// Pushes a view controller on top of the current view
    static func pushController(_ controller: UIViewController){
        findNavigationController(viewController: UIApplication.shared.windows.filter { $0.isKeyWindow }.first?.rootViewController)!.pushViewController(controller, animated: true)
    }
    
    /// Allows a function to do actions with the current navigation controller
    static func navigationAction(_ action: ((UINavigationController)->())) {
        action(findNavigationController(viewController: UIApplication.shared.windows.filter { $0.isKeyWindow }.first?.rootViewController)!)
        
    }

    
    /// Goes through the application window to find the navigation controller
  static private func findNavigationController(viewController: UIViewController?) -> UINavigationController? {
    guard let viewController = viewController else {
      return nil
    }

    if let navigationController = viewController as? UINavigationController {
      return navigationController
    }

    for childViewController in viewController.children {
      return findNavigationController(viewController: childViewController)
    }

    return nil
  }
}

extension UIApplication {
    
    var keyWindow: UIWindow? {
        return UIApplication.shared.connectedScenes
            .filter { $0.activationState == .foregroundActive }
            .first(where: { $0 is UIWindowScene })
            .flatMap({ $0 as? UIWindowScene })?.windows
            .first(where: \.isKeyWindow)
    }
    
}

Sometimes, it is hard to call methods on NavigationView in SwiftUI and that is when we start missing the UIKit features but here is the class which works like magic and relies on UIAppication window and lets you do everything that one could do with UIKit UINavigaitonController.

Do you have an example of this?

Yep! If you wanna pop to root view or trigger pushController without clicking a button (maybe you are performing a .task {} ) , this is a better option.

PS: I used this for pushing controller in SwiftUI views when shareplay activity was recognized.

struct FirstView: View {
    var body: some View {
        NavigationView {
            NavigationLink(destination: SecondView()){
                Text("Go to another view")
            }
        }
    }
}

struct SecondView : View {
    var body: some View {
        Button("Go to root view") {
                        // popping to root without EnvironmentObject
            NavigationController.navigationAction { navigationController in
                navigationController.popToRootViewController(animated: true)
            }
        }.onAppear {
        // triggering a push or pop to root based on a timer or urlsession completion or async task
            Timer.scheduledTimer(withTimeInterval: 3, repeats: false) { _ in
                NavigationController.navigationAction { controller in
                    var view = Color.red
                    var viewController = UIHostingController(rootView: view)
                    controller.pushViewController(viewController, animated: true)
                }
            }
        }
        
    }
}

Thanks! Do you think we can use this without NavigationView? and have a UINavigationController as the main controller that handles the FirstView?

Yep, it works with that too