Im trying to use new functionality of navigation in SwiftUI and now I've problem with similar early problem in NavigationLink when destination view created more than twice. Could you please help me to find right solution.
As you can see the WelcomeViewModel created multiple times. I'm tried add a specific id to make view/viewModel unique, but it's didn't help.
enum Step: String, Identifiable {
case page1
case page2
case page3
var id: String {
self.rawValue
}
}
class Router: ObservableObject {
@Published var steps: [Step] = []
static let shared = Router()
private init(){}
func showPage1() {
steps.append(.page1)
}
func showPage2() {
steps.append(.page2)
}
func showPage3() {
steps.append(.page3)
}
func popToRoot() {
steps.removeAll()
}
}
class BaseStepViewModel: ObservableObject {
let step: Step
let router: Router
init(step: Step, router: Router) {
self.step = step
self.router = router
print("Created step \(step.rawValue)")
}
func shopNextPage() {
router.showPage2()
}
}
class Step1ViewModel: BaseStepViewModel { }
class Step2ViewModel: BaseStepViewModel {
override func shopNextPage() {
router.showPage3()
}
}
class Step3ViewModel: BaseStepViewModel {
override func shopNextPage() {
router.popToRoot()
}
}
struct StepView: View {
@StateObject var viewModel: BaseStepViewModel
var body: some View {
Button {
viewModel.shopNextPage()
} label: {
Text(viewModel.step.rawValue)
}
}
}
class WelcomeViewModel: ObservableObject, Identifiable {
let title: String
let router: Router
var id: String {
title
}
init(title: String, router: Router) {
self.title = title
self.router = router
print("Created welcome view")
}
func startFlow() {
router.showPage1()
}
}
struct WelcomeView: View {
@StateObject var viewModel: WelcomeViewModel
var body: some View {
Button {
viewModel.startFlow()
} label: {
Text(viewModel.title)
}
}
}
struct RootView: View {
@StateObject var router = Router.shared
var body: some View {
NavigationStack(path: $router.steps) {
WelcomeView(viewModel: .init(title: "Welcome", router: router))
.id("Welcome")
.navigationDestination(for: Step.self) { step in
switch step {
case .page1:
StepView(viewModel: Step1ViewModel(step: step, router: router))
case .page2:
StepView(viewModel: Step2ViewModel(step: step, router: router))
case .page3:
StepView(viewModel: Step3ViewModel(step: step, router: router))
}
}
}
}
}