Description
For programatic navigation you could previously use NavigationLink(isActive:, destination:, label:) which would fire navigation when the isActive param is true. In IOS 16 this became deprecated and NavigationStack, NavigationLink(value:, label:) and NavigationPath was introduced.
To read about the usage of these follow the links:
https://developer.apple.com/documentation/swiftui/migrating-to-new-navigation-types https://www.hackingwithswift.com/articles/250/whats-new-in-swiftui-for-ios-16 (search for NavigationStack)
My question is how should I use and maintain the array with the content of the navigation stack (like the NavigationPath object) if I'd like to use it in different Views and in their ViewModels?
As you can see in the code below I created a NavigationPath object to hold my navigation stack in the BaseView or BaseView.ViewModel. This way I can do programatic navigation from this BaseView to other pages (Page1, Page2), which is great.
But if I go to Page1 and try to navigate from there to Page2 programatically I need to have access to the original NavigationPath object object, the one that I use in BaseView.
What would be the best way to access this original object?
It is possible that I misunderstand the usage of this new feature but if you have any possible solutions for programatic navigation from a ViewModel I would be glad to see it :)
Code
What I've tried to do:
struct BaseView: View {
@StateObject var viewModel = ViewModel()
var body: some View {
NavigationStack(path: $viewModel.paths) {
VStack {
Button("Page 1", action: viewModel.goToPage1)
Button("Page 2", action: viewModel.goToPage2)
}
.navigationDestination(for: String.self) { stringParam in
Page1(stringParam: stringParam)
}
.navigationDestination(for: Int.self) { intParam in
Page2(intParam: intParam)
}
}
}
}
extension BaseView {
@MainActor class ViewModel: ObservableObject {
@Published var paths = NavigationPath()
func goToPage1() {
let param = "Some random string" // gets the parameter from some calculation or async network call
paths.append(param)
}
func goToPage2() {
let param = 19 // gets the parameter from some calculation or async network call
paths.append(param)
}
}
}
struct Page1: View {
@StateObject var viewModel = ViewModel()
let stringParam: String
var body: some View {
VStack {
Button("Page 2", action: viewModel.goToPage2)
}
}
}
extension Page1 {
@MainActor class ViewModel: ObservableObject {
func goToPage2() {
// Need to add value to the original paths variable in BaseView.ViewModel
}
}
}
struct Page2: View {
@StateObject var viewModel = ViewModel()
let intParam: Int
var body: some View {
Text("\(intParam)")
}
}
extension Page2 {
@MainActor class ViewModel: ObservableObject {
}
}
paths. You shall have only oneViewModelclass for all your code, and share the same instance with all views. – Biophysics