Question

我对Swift和开发都是100％全新的。我已经读了几本书，并且开始了解它，但是我可能犯了一些愚蠢的错误。

问题是我有一个列表，其中显示了Measurements（）的集合，并且我试图获取NavigationLink，因此当发生触摸时，EditMeasurementView将打开。我不确定自己在做什么错。

这是EditMeasurementView：

struct EditMeasurementView: View {
    @Binding var measurements: Measurements

    var body: some View {
        Text(/*@START_MENU_TOKEN@*/"Hello, World!"/*@END_MENU_TOKEN@*/)
    }
}

struct EditMeasurementView_Previews: PreviewProvider {
    static var previews: some View {
      //EditChecklistItemView(checklistItem: .constant(ChecklistItem(name: "Sample item")))
          EditMeasurementView(measurements:  .constant(Measurements()))
    }
}

这是ContentView：

import SwiftUI

struct ContentView: View {

    @ObservedObject var measurements = Measurements()
    @State var newMeasurementViewIsVisible = false

    var body: some View {
        NavigationView {
            List {
                ForEach(measurements.items) { MeasurementItem in
                    NavigationLink(destination: EditMeasurementView(measurements: $measurements)) {
                        HStack {
                            Text("\(MeasurementItem.mdate)")
                            Spacer()
                            Text("\(MeasurementItem.weight)" + " lbs")
                        }
                    }
                }
                .onDelete(perform: measurements.deleteListItem)
                .onMove(perform: measurements.moveListItem)
            }
            .navigationBarTitle("Measurements", displayMode: .inline)
            .navigationBarItems(
                leading: Button(action: { self.newMeasurementViewIsVisible = true
                  }) {
                    HStack {
                      Image(systemName: "plus.circle.fill")
                      Text("New")
                    }
                  },
                  trailing: EditButton()
            )
        }
        .sheet(isPresented: $newMeasurementViewIsVisible) {
            NewMeasurementItemView(measurements: self.measurements)
        }
    }
} 


struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

迅速引发的错误是：

Cannot convert value of type 'ObservedObject<Measurements>.Wrapper' to
expected argument type 'Binding<Measurements>'" on the NavigationLink
line in ContentView.

Answer 1

///想通了！ ///

在EditMeasurementView中，我绑定到了错误的对象。我应该绑定到MeasurementItem而不是Measurements。 Measurements是包含MeasurementItems的数组，但是这里我只编辑了一组MeasurementItems。

NavigationLink绑定问题

1 个答案: