SwiftUI自定義文本欄位未獲得更新值

我想創建一個帶有一些輸入按鈕的自定義文本欄位，單擊這些按鈕文本欄位應該相應地更新值。

我有多個選項可以在 中設定值InputView，因此，如果我進行了編輯InputView并且單擊了任何按鈕，則該按鈕應更新該值。

這是我的代碼

@main
struct AmountApp: App {
    var body: some Scene {
        WindowGroup {
            InputView()
        }
    }
}
struct InputView: View {
    @State var value: Double = 0.00
    var body: some View {
        VStack {
            Text("Amount")
            TextInput(value: $value).padding(.horizontal)
            HStack(alignment: .center, spacing: 16) {
                Button { value = 20 } label: { Text("20") }
                Button { value = 30 } label: { Text("30") }
                Button { value = 40 } label: { Text("40") }
            }
            
            Button { print(value) } label: {
                Text("Print")
                    .padding(8)
                    .foregroundColor(.red)
            }
        }
    }
}


struct TextInput: UIViewRepresentable {
    @Binding var value: Double
    
    func makeCoordinator() -> Coordinator { Coordinator(self) }
    
    func updateUIView(_ uiView: UITextField, context: Context) { }
    
    func makeUIView(context: Context) ->  UITextField {
        let textfield = UITextField()
        textfield.placeholder = "Enter amount"
        textfield.text = "\(value)"
        textfield.keyboardType = .decimalPad
        textfield.setContentHuggingPriority(.defaultHigh, for: .vertical)
        textfield.setContentHuggingPriority(.defaultLow, for: .horizontal)
        textfield.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        return textfield
    }
    
    class Coordinator: NSObject, UITextFieldDelegate {
        var parent: TextInput
        init(_ textField: TextInput) { self.parent = textField }
    }
}

幫助將不勝感激，?美好的一天。！

uj5u.com熱心網友回復：

如果您不實作UITextFieldDelegate接收用戶輸入的方法（SwiftUI Custom TextField with UIViewRepresentable Issue with ObservableObject and push View） ，系結值將不會更新

當您從 SwiftUI 端更改值時，您的 UIViewRepresentable 需要處理 updateUIView 中的更改（將新值傳遞給 UITextField）

還記得設定textfield.delegate = context.coordinator以便您接收事件。

struct TextInput: UIViewRepresentable {
    @Binding var value: Double
    
    func makeCoordinator() -> Coordinator { Coordinator(self) }
    
    // for handling swiftui-side modification to the binding (your buttons)
    func updateUIView(_ uiView: UITextField, context: Context) { 
        uiView.text = value
    }
    
    func makeUIView(context: Context) ->  UITextField {
        let textfield = UITextField()
        textfield.placeholder = "Enter amount"
        textfield.text = "\(value)"
        textfield.keyboardType = .decimalPad
        textfield.setContentHuggingPriority(.defaultHigh, for: .vertical)
        textfield.setContentHuggingPriority(.defaultLow, for: .horizontal)
        textfield.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
        textfield.delegate = context.coordinator // set the delegate
        return textfield
    }
    
    class Coordinator: NSObject, UITextFieldDelegate {
        var parent: TextInput
        init(_ textField: TextInput) { self.parent = textField }
        func textFieldDidEndEditing(_ textField: UITextField) {
            if let text = textField.text {
                parent.value = Double(text) ?? 0
            } else {
                parent.value = 0
            }
        }
    }
}

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