SwiftUI NavigationLink 多选问题

Question

我对 SwiftUI 导航有疑问。为了说明这个问题，我做了一个汽车列表的简单示例，如果用户点击它，它会显示汽车详细信息：

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)
    }
}

当您当时选择一辆车时，这很有效。不幸的是，使用 swiftUI 我无法禁用多选。如果用户同时选择多辆汽车，然后有时会返回汽车列表，我会收到错误日志：

SwiftUI encountered an issue when pushing aNavigationLink. Please file a bug.

此时，汽车列表不再响应。它需要很少的尝试，但它最终会发生。到目前为止，我只能在 iOS 15 上复制它。我也尝试在没有 viewModel 的情况下这样做，但它仍然会发生。 理想情况下，我希望将 NavigationLink 保留在 VStack 中，因为当用户选择它时，它会使行变暗。

Answer 1

我可以重现您的问题，我认为这是一个错误。 但是，将以下 NavigationLink 设置与 selection 和 tag 一起使用似乎对我有用。

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)
    }
}