swiftUIloop.swift

import SwiftUI

class AppState: ObservableObject {
    @Published var screenAState: Bool = false
    @Published var screenBState: Bool = false
}

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?
    lazy var appState = AppState()

    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {

        let contentView = NavigationView {
            ScreenA()
        }
        .environmentObject(appState)

        if let windowScene = scene as? UIWindowScene {
            let window = UIWindow(windowScene: windowScene)
            window.rootViewController = UIHostingController(rootView: contentView)
            self.window = window
            window.makeKeyAndVisible()
        }
    }
}

struct ScreenA: View {
    @EnvironmentObject var appState: AppState

    var body: some View {
        NavigationLink(destination: ScreenB(), isActive: $appState.screenAState) {
            Text("Go to B")
        }.isDetailLink(false)
    }
}

struct ScreenB: View {
    @EnvironmentObject var appState: AppState

    var body: some View {
        NavigationLink(destination: ScreenB(), isActive: $appState.screenBState) {
            Text("Go to A")
        }.isDetailLink(false)
    }
}