How to present a View without embedding it into a current navigation flow in SwiftUI?

Question

I have a logging onboarding being finished, and I need to present a HomeView, which knows nothing about previous navigation flow.

var body: some View {
    if viewModel.isValidated {
       destination()
    } else {
       LoadingView()
    }

Doing it this way I have a navigation bar at the top of destination(). I guess I can hide it, but it would still be the same navigation flow and I need to start a new one. How can I achieve that?(iOS 13)

Answer 1

One way to handle this is with an @Environment object created from a BaseViewModel. The way that this works is to essentially control the state of the presented view from a BaseView or a view controller. I'll attempt to simplify it for you the best I can.

class BaseViewModel: ObservableObject {
    @Published var baseView: UserFlow = .loading

    init() {
         //Handle your condition if already logged in, change 
         //baseView to whatever you need it to be. 
    }
    
    enum UserFlow {
        case loading, onboarding, login, home
    }
}

Once you've setup your BaseViewModel you'll want to use it, I use it in a switch statement with a binding to an @EnvironmentObject so that it can be changed from any other view.

struct BaseView: View {
    @EnvironmentObject var appState: BaseViewModel
    
    var body: some View {
        Group {
            switch appState.userFlow {
            case .loading:
                LoadingView()
            case .onboarding:
                Text("Not Yet Implemented")
            case .login:
                LandingPageView()
            case .home:
                BaseHomeScreenView().environmentObject(BaseHomeScreenViewModel())
            }
        }
    }
}

Your usage, likely at the end of your register/login flow, will look something like this.

struct LoginView: View {

@EnvironmentObject var appState: BaseViewModel

    var body: some View {
        Button(action: {appState = .home}, label: Text("Log In"))
    }
}

So essentially what's happening here is that you're storing your app flow in a particular view which is never disposed of. Think of it like a container. Whenever you change it, it changes the particular view you want to present. The especially good thing about this is that you can build a separate navigation hierarchy without the use of navigation links, if you wanted.