SwiftUI TimePicker 绑定到父视图的视图

Question

你好，我想对我的要求提出一些建议。 我有一个父视图，它有一个子视图，还有一个子视图。 基本上，我想将绑定的值传递给父视图。 Parent View (SubChildView-Value) -> Child View -> SubChildView （从这里传递到父视图）。 下面是我写的逻辑。

  struct Parent: View {
    @State var dateChosen: Date = Date()
    var dateToDisplay: Date

    var body: some View {
        ChildPickerView(pickerType: .DatePicker, chosenDate: $dateChosen)
             // If I uncomment the below onChange lines, the binding from subchild would work
             //.onChange(of: dateChosen) { newValue in
            //    dateChosen = newValue
            // }
        Text("Date Selected: \(**dateChosen**)") // I would like this value to be read from SubChildPickerView ?!! How to achieve this ?
    }
}


struct Parent_Previews: PreviewProvider {
    static var previews: some View {
        VStack {
            ChildPickerView(dateChosen: Date(), dateToDisplay: .now)
        }.padding(16.0)
    }
}

struct ChildPickerView: View {
    @State var pickerType: PickerType
    @State var selectedDate: Date = Date()
    @Binding var chosenDate: Date

    var body: some View {
            SubChildPickerView(selectedDate: $selectedDate)
//    If I uncomment the below lines, the bindings to the parent view works
//                .onChange(of: selectedDate) { newValue in
//                    chosenDate = newValue
//                }
            Text("picker view: \(selectedDate)")
    }

    struct SubChildPickerView: View {
        @Binding var selectedDate: Date // Can I get rid of this binding here or somehow make this value being read by ParentPickerView?

        var body: some View {
            let datePicker = DatePicker("", selection: **$selectedDate,**
                                        in: Date()...,
                                        displayedComponents: .hourAndMinute)
                .datePickerStyle(.wheel)
                .padding()

            VStack {
                GeometryReader { geometry in
                    datePicker
                        .frame(width: geometry.size.width, height: geometry.size.height)
                        .clipped()
                }
            }
        }
    }
}

Answer 1

谢谢。 我已经设法使用绑定解决了这个问题。 下面是代码。

 struct ParentView: View {
    @State var selectedDate: Date = Date()

    var body: some View {
        ChildPickerView(selectedDate: $selectedDate)
        Text("subchild chosen date view \(selectedDate)")
    }
}

struct ParentView_Previews: PreviewProvider {
    static var previews: some View {
        VStack {
            ParentView(selectedDate: Date())
        }.padding(16.0)
    }
}

struct ChildPickerView: View {
    @Binding var selectedDate: Date

    var body: some View {
        PickerView(selectedDate: $selectedDate, pickerType: pickerType)
    }

    struct SubChildPickerView: View {
        @Binding var selectedDate: Date

        var body: some View {
            let datePicker = DatePicker("", selection: $selectedDate,
                                        in: Date()...,
                                        displayedComponents: .hourAndMinute)
                .datePickerStyle(.wheel)
                .padding()

            VStack {
                GeometryReader { geometry in
                    datePicker
                        .frame(width: geometry.size.width, height: geometry.size.height)
                        .clipped()
                }
            }
        }
    }
}