SwiftUI NavigationLink issue with multi selections - swiftui

Question

I have an issue with SwiftUI navigation. To show the issue I made a simple example of a list of cars and if the user clicks on it, it shows the car details:
struct ContentView: View {
var cars = [Car(name: "A"), Car(name: "B"), Car(name: "C"), Car(name: "D")]
var body: some View {
NavigationView {
LazyVStack(spacing: 10) {
ForEach(cars, id: \.self) { car in
NavigationLink(destination: {
CarDetailsView(viewModel: CarDetailsViewModel(car: car))
},
label: {
CarRowView(car: car)
})
}
}
}
}
}
struct CarDetailsView: View {
#StateObject var viewModel: CarDetailsViewModel
#Environment(\.presentationMode) private var presentationMode
var body: some View {
Button("Back") {
presentationMode.wrappedValue.dismiss()
}
}
}
class CarDetailsViewModel: ObservableObject {
#Published var car: Car
init(car: Car) {
self.car = car
}
}
struct Car: Hashable {
var name: String
}
struct CarRowView: View {
var car: Car
var body: some View {
Text(car.name)
}
}
This works well when you select one car at the time. Unfortunatly with swiftUI I cannot disabled multi selection. If the user select multiple cars at the same time, and then go back to the car list sometime I get an error log:
SwiftUI encountered an issue when pushing aNavigationLink. Please file a bug.
At that moment, the car list is no longer responsive. It takes few attempt but it does eventually happen. I can only replicate this on iOS 15 so far. I also tried to do this without the viewModel and it still happen.
Ideally I want to keep the NavigationLink inside the VStack because it makes the row dimming when the user selects it.

Answer 1

I can reproduce your issue, and I think this is a bug.
However using the following NavigationLink setup with selection and tag seems to works for me.
struct ContentView: View {
#State var cars = [Car(name: "A"), Car(name: "B"), Car(name: "C"), Car(name: "D")]
#State private var showCar: UUID?
var body: some View {
NavigationView {
LazyVStack(spacing: 30) {
ForEach(cars) { car in
NavigationLink(
destination: CarDetailsView(car: car),
tag: car.id,
selection: $showCar,
label: { CarRowView(car: car) }
)
}
}
}
}
}
struct CarDetailsView: View {
#Environment(\.dismiss) private var dismiss
#State var car: Car
var body: some View {
Button("Back \(car.name)") {
dismiss()
}
}
}
struct Car: Identifiable, Hashable {
let id = UUID()
var name: String
}
struct CarRowView: View {
var car: Car
var body: some View {
Text(car.name)
}
}