SwiftUI：检测 NavigationView 返回主视图

Question

我有一个NavigationView和以下视图结构ViewA -> ViewB -> ViewC，我试图弄清楚如何检测 ViewB 何时返回 ViewA ViewB -> ViewA。这是我的代码：

struct ViewA: View {
    var body: some View {
        NavigationView {
            NavigationLink{
                ViewB()
            }label: {
                Text("Go to ViewB")
                
            }
        }
    }
}

struct ViewB: View {
    @Environment(\.presentationMode) var presentationMode: Binding
    var body: some View {
        NavigationLink{
            ViewC()
        }label: {
            Text("Go to ViewC")
        }
        .onAppear{
            print("onAppear \(presentationMode.wrappedValue.isPresented)")
        }
        .onDisappear{
            print("onDisappear \(presentationMode.wrappedValue.isPresented)")
        }
    }
}

struct ViewC: View {
    var body: some View {
        Text("ViewC")
    }
}

使用以下代码：

        .onAppear{
            print("onAppear \(presentationMode.wrappedValue.isPresented)")
        }
        .onDisappear{
            print("onDisappear \(presentationMode.wrappedValue.isPresented)")
        }

使用上面的代码我可以检测 ViewC 何时变为 ViewB （每个控制台输出onAppear true）。但我的问题是如何检测何时ViewB -> ViewA。

你们中的任何人都知道如何实现这一点，或者是否有办法检测到这一点？

我非常感谢你的帮助

Answer 1

这是一个基于新解决方案的解决方案NavigationStack，它可以让您记录导航路径（如 @workingdog 提到的）：

struct ViewA: View {
    
    @State private var navigationPath: [String] = []
    
    var body: some View {
        NavigationStack(path: $navigationPath) {
            NavigationLink(value: "B") {
                Text("Go to ViewB")
            }
            .navigationDestination(for: String.self) { destination in
                if destination == "B" {
                    ViewB()
                } else {
                    ViewC()
                }
            }
        }
        .onChange(of: navigationPath) { newValue in
            print(newValue)
            if newValue == [] {
                print("Coming from ViewB to ViewA") // trigger your action here
            }
        }
    }
}

struct ViewB: View {

    var body: some View {
        NavigationLink(value: "C") {
            Text("Go to ViewC")
        }
    }
}

struct ViewC: View {
    
    var body: some View {
        Text("ViewC")
    }
}