SwiftUI Half-swipe back from navigation causes error - swiftui

Question

I noticed issue in SwiftUI when using NavigationStack
Once I swipe-back on a half and revert it -> it stops working
Also I attached sample code if you want to try it
import SwiftUI
struct ContentView: View {
var body: some View {
NavigationStack {
ListView()
}
}
}
struct ListView: View {
var body: some View {
List {
NavigationLink(destination: ViewA(viewModel: .init()), label: {
Text("A")
})
NavigationLink(destination: ViewB(), label: {
Text("B")
})
}
}
}
struct ViewA: View {
#StateObject var viewModel: Observed
var body: some View {
ZStack {
List {
Button(action: {
viewModel.action()
}, label: {
Text("label")
})
}
NavigationLink(isActive: $viewModel.shouldShowViewB, destination: {
ViewB()
}, label: {EmptyView()})
}
.navigationTitle("view a")
}
}
struct ViewB: View {
var body: some View {
List {
Button(action: {
print("actionb")
}, label: {
Text("labelb")
})
}
.navigationTitle("view b")
}
}
class Observed: ObservableObject {
#Published var shouldShowViewB = false
func action() {
print("action from model")
shouldShowViewB = true
}
}
Expected: whatever I do it should work as expected - when I tap it should open new view
Anyone else found this issue? How to fix it?

Answer 1

Issue 1 is you create the ObservedObject inside the NavigationLink with .init and then have a #StateObject declaration in the Subview ViewA(). That doesn't feel right. Create the Object with #StateObject in the parent view and pass it down.
Issue 2 is the new SwiftUI Navigation model, with NavigationLink)destination: label:) being deprecated. I adapted your code to the new navigation logic:
struct ContentView: View {
var body: some View {
NavigationStack {
ListView()
}
}
}
struct ListView: View {
#StateObject var viewModel = Observed() // create ObservedObject here
var body: some View {
List {
NavigationLink("A") {
ViewA(viewModel: viewModel) // pass down
}
NavigationLink("B") {
ViewB()
}
}
}
}
struct ViewA: View {
#ObservedObject var viewModel: Observed // passed down Object
var body: some View {
ZStack {
List {
Button(action: {
viewModel.action()
print(viewModel.shouldShowViewB)
}, label: {
Text("label")
})
}
.navigationDestination(isPresented: $viewModel.shouldShowViewB, destination: { ViewB() })
}
.navigationTitle("view a")
}
}
struct ViewB: View {
var body: some View {
List {
Button(action: {
print("actionb")
}, label: {
Text("labelb")
})
}
.navigationTitle("view b")
}
}
class Observed: ObservableObject {
#Published var shouldShowViewB = false
func action() {
print("action from model")
shouldShowViewB = true
}
}