binding - SwiftUI & UITextField ViewModel 绑定问题

Question

我正在尝试在 SwiftUI 中使用 UITextField 。我为 UITextField 创建了一个自定义结构，并创建了一个可绑定字符串，它包含输入文本。当我尝试将输入文本传递回 viewModel 时，它不起作用。为了比较，我将 SwiftUI Textfield 放在代码中并且它可以工作有人可以帮忙吗？

import SwiftUI

final class RegistrationViewViewModel: ObservableObject {
    @Published var firstName: String = "" {
        didSet {
            print(oldValue)
        }
        willSet {
            print(newValue)
        }
    }

    @Published var lastName: String = "" {
        didSet {
            print(oldValue)
        }
        willSet {
            print(newValue)
        }
    }

    func saveData() {
        print("Saving...", firstName, lastName)
    }
}


struct RegistrationView: View {
    @ObservedObject var viewModel = RegistrationViewViewModel()

    var body: some View {
        VStack(spacing: 50) {
            TextField("Last name", text: $viewModel.lastName)
                .frame(width: 300, height: 35, alignment: .center)
                .border(Color(.systemGray))

            CustomTextField(inputText: $viewModel.firstName, placeholder: "First name")
                .frame(width: 300, height: 35, alignment: .center)
                .border(Color(.systemGray))

            Button(action: {
                self.viewModel.saveData()
            }) {
                Text("Submit")
            }
        }
    }
}
struct CustomTextField: UIViewRepresentable {
    var inputText: Binding<String>
    var placeholder: String

    func makeUIView(context: Context) -> UITextField {
        let textfield = UITextField(frame: .zero)
        textfield.delegate = context.coordinator
        textfield.placeholder = placeholder
        return textfield
    }

    func updateUIView(_ uiView: UITextField, context: Context) {}

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    class Coordinator: NSObject, UITextFieldDelegate {
        var parent: CustomTextField

        init(_ parent: CustomTextField) {
            self.parent = parent
        }

        func textFieldShouldReturn(_ textField: UITextField) -> Bool {
            textField.resignFirstResponder()
            return true
        }
    }
}

标签： bindinguitextfieldswiftuiviewmodeltextfield

Answer 1

尝试如下设置你的 updateUIView 函数：

func updateUIView(_ uiView: UITextField, context: Context) {
     uiView.text = inputText
}