SwiftUI

Question

我在上层创建了一个带有按钮的列表视图。我想在用户单击 NavigationLink 并且在详细视图中看不到它后立即隐藏按钮。

我使用@State var showAddButton实现成功，并通过onDisappear和onAppear操作控制它，如下所示，但如果主视图不消失，按钮不会消失完全地。

有没有人有任何其他解决方案来触发其他操作并保留 NavigationLink 的原始 link 操作？

@State var showAddButton = true

    var body: some View {

        ZStack{

            NavigationView{
                List{
                    ForEach(items, id: \.id){ item in
                        NavigationLink(destination: WorkItemDetailView(item: item)){
                            WorkItemListRow(item: item)
                        }.onDisappear{self.showAddButton = false}
                            .onAppear{self.showAddButton = true}

                    }
                }
                .navigationBarTitle("List", displayMode: .inline)   
            }           

            if showAddButton {
                FloatAddButton()
            }
        }
    }

Answer 1

如果你想将该按钮粘贴到主视图，你可以切换 ZStack 的位置：

   NavigationView{
        ZStack{
        List{
            ForEach(items, id: \.self){ item in
                NavigationLink(destination: WorkItemDetailView(item: item)){
                    WorkItemListRow(item: item)
                }

            }

        }
        .navigationBarTitle("List", displayMode: .inline)
        Button("mybutton",action: {})}
    }

Answer 2

你也可以这样使用

struct NavigationBlock<Destination: View, Content: View>: View {
    @State private var isActive: Bool = false
    var destination: Destination
    var content: (Binding<Bool>) -> Content
    init(destination: Destination, @ViewBuilder content: @escaping (Binding<Bool>) -> Content) {
        self.destination = destination
        self.content = content
    }

    var body: some View {
        Group {
            content($isActive)
            NavigationLink(destination: destination,
                           isActive: $isActive) { Spacer() }.hidden()
        }
    }
}

用法：

struct ContentView: View {
    var body: some View {
        NavigationView {
            NavigationBlock(destination: Text("Hello")) { binding in
                Button(action: {
                    print("User did tap 'Hello' button")
                    binding.wrappedValue = true
                }) { Text("Hello button") }
            }
        }
    }
}

SwiftUI - 单击 NavigationLink 时触发其他操作

SwiftUI - Trigger other actions when click NavigationLink

ios

navigationlink