Ios 当所有文本字段在SwiftUI中都有值时，如何动态更新屏幕上的标签？

我正在开发一个应用程序，允许用户使用两个单独的文本字段输入下注的赔率。例如，假设用户想要的几率是3/1。用户需要在一个字段中输入3，在另一个字段中输入1

我有两个状态变量：

• leftOddsVal
• 右奥德斯瓦尔

这是我在CustomTextField中使用它们的方式：

CustomTextfield(text: $leftOddsVal, placeHolder: "Enter text", keyboardType: .numberPad)
CustomTextfield(text: $rightOddsVal, placeHolder: "Enter text", keyboardType: .numberPad)
CustomTextfield(text: $state, placeHolder: "Enter text", keyboardType: .numberPad)

struct CustomTextfield: UIViewRepresentable {

    @Binding var text : String
    var placeHolder: String
    var keyboardType: UIKeyboardType

    final class Coordinator: NSObject {

        var textField: CustomTextfield

        init(_ textField: CustomTextfield) {
            self.textField = textField
        }

    }

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

    func makeUIView(context: Context) -> UITextField {

        let textField = UITextField()
        textField.backgroundColor = .white
        textField.placeholder = self.placeHolder
        textField.keyboardType = self.keyboardType

        return textField
    }

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

    }

}

这是自定义文本字段的代码：

CustomTextfield(text: $leftOddsVal, placeHolder: "Enter text", keyboardType: .numberPad)
CustomTextfield(text: $rightOddsVal, placeHolder: "Enter text", keyboardType: .numberPad)
CustomTextfield(text: $state, placeHolder: "Enter text", keyboardType: .numberPad)

struct CustomTextfield: UIViewRepresentable {

    @Binding var text : String
    var placeHolder: String
    var keyboardType: UIKeyboardType

    final class Coordinator: NSObject {

        var textField: CustomTextfield

        init(_ textField: CustomTextfield) {
            self.textField = textField
        }

    }

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

    func makeUIView(context: Context) -> UITextField {

        let textField = UITextField()
        textField.backgroundColor = .white
        textField.placeholder = self.placeHolder
        textField.keyboardType = self.keyboardType

        return textField
    }

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

    }

}

我想做什么：

CustomTextfield(text: $leftOddsVal, placeHolder: "Enter text", keyboardType: .numberPad)
CustomTextfield(text: $rightOddsVal, placeHolder: "Enter text", keyboardType: .numberPad)
CustomTextfield(text: $state, placeHolder: "Enter text", keyboardType: .numberPad)

struct CustomTextfield: UIViewRepresentable {

    @Binding var text : String
    var placeHolder: String
    var keyboardType: UIKeyboardType

    final class Coordinator: NSObject {

        var textField: CustomTextfield

        init(_ textField: CustomTextfield) {
            self.textField = textField
        }

    }

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

    func makeUIView(context: Context) -> UITextField {

        let textField = UITextField()
        textField.backgroundColor = .white
        textField.placeholder = self.placeHolder
        textField.keyboardType = self.keyboardType

        return textField
    }

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

    }

}

我想获取每个字段的值，并编写一些逻辑，计算出赢和输的金额，然后更新屏幕上的一些文本标签。我希望在所有字段都有值后自动更新赢/输标签，而不是让用户在看到他们可能赢或输的内容之前提交表单

以下是标签的外观：

问题：

CustomTextfield(text: $leftOddsVal, placeHolder: "Enter text", keyboardType: .numberPad)
CustomTextfield(text: $rightOddsVal, placeHolder: "Enter text", keyboardType: .numberPad)
CustomTextfield(text: $state, placeHolder: "Enter text", keyboardType: .numberPad)

struct CustomTextfield: UIViewRepresentable {

    @Binding var text : String
    var placeHolder: String
    var keyboardType: UIKeyboardType

    final class Coordinator: NSObject {

        var textField: CustomTextfield

        init(_ textField: CustomTextfield) {
            self.textField = textField
        }

    }

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

    func makeUIView(context: Context) -> UITextField {

        let textField = UITextField()
        textField.backgroundColor = .white
        textField.placeholder = self.placeHolder
        textField.keyboardType = self.keyboardType

        return textField
    }

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

    }

}

textfielddidediting委托方法需要知道要触发的方法。这意味着，我需要修改CustomTextField以触发viewModel中将触发的方法。然后我可以触发赢/输计算方法。然而，我开始觉得这是一个如此简单的工作很多。看起来很乱

我无法直接访问视图中的文本字段值。如果我使用SwiftUI的TextField组件，这将很简单。然而，正如您在上面的代码中所看到的，我正在使用UIKit的UIExtField组件包装在UIRepresentable结构中

我所尝试的：

CustomTextfield(text: $leftOddsVal, placeHolder: "Enter text", keyboardType: .numberPad)
CustomTextfield(text: $rightOddsVal, placeHolder: "Enter text", keyboardType: .numberPad)
CustomTextfield(text: $state, placeHolder: "Enter text", keyboardType: .numberPad)

struct CustomTextfield: UIViewRepresentable {

    @Binding var text : String
    var placeHolder: String
    var keyboardType: UIKeyboardType

    final class Coordinator: NSObject {

        var textField: CustomTextfield

        init(_ textField: CustomTextfield) {
            self.textField = textField
        }

    }

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

    func makeUIView(context: Context) -> UITextField {

        let textField = UITextField()
        textField.backgroundColor = .white
        textField.placeholder = self.placeHolder
        textField.keyboardType = self.keyboardType

        return textField
    }

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

    }

}

我有一个视图模型，我试图将其传递到CustomtextField

我只是这样声明了我的环境变量：

   struct CustomTextfield: UIViewRepresentable {

      @EnvironmentObject var viewModel: EnvironmentObject<AnyObject>
      @Binding var text : String
      var placeHolder: String
      var keyboardType: UIKeyboardType

   CustomTextfield(viewModel: betViewModel as! EnvironmentObject<BetViewModel>, value: $oddsLeftValue, placeHolder: "Enter text", keyboardType: .numberPad)

但我得到了以下错误：

Type 'AnyObject' does not conform to protocol 'ObservableObject'

我还尝试将绑定文本值设置为textField的值，但这也不起作用

我希望有人能让我了解我做错了什么。我觉得我好像在兜圈子，这是因为试图重用UIRepresentable UIKit组件。这似乎限制了我，这导致了一些变通办法，对于我试图实现的目标来说，这些变通办法似乎是过火了

我想做的就是允许用户输入他们的赔率和赌注，并让赢/输标签动态更新，而无需点击任何按钮。同时能够重用CustomTextField

期待您的建议。

---

提前感谢。

以下内容使您的自定义文本字段可操作。。。对于更新外部绑定，希望这就是这么长描述的目标

使用Xcode 11.4/iOS 13.4进行测试

末尾的小

TestCustomTextfield

用于检查

CustomTextfield

中更改的更新标签

struct CustomTextfield: UIViewRepresentable {

    @Binding var text : String
    var placeHolder: String
    var keyboardType: UIKeyboardType

    final class Coordinator: NSObject, UITextFieldDelegate {

        var parent: CustomTextfield

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

        func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
            parent.text = textField.text ?? ""
            return true
        }
    }

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

    func makeUIView(context: Context) -> UITextField {

        let textField = UITextField()
        textField.backgroundColor = .white
        textField.placeholder = self.placeHolder
        textField.keyboardType = self.keyboardType
        textField.setContentHuggingPriority(.required, for: .vertical)
        textField.delegate = context.coordinator

        return textField
    }

    func updateUIView(_ uiField: UITextField, context: Context) {
        if let text = textField.text as NSString? {
           parent.text = text.replacingCharacters(in: range, with: string)
        } else {
           parent.text = ""
        }
     }

}

struct TestCustomTextfield: View {
    @State private var value = ""
    var body: some View {
        VStack {
            Text("Label: \(value)")
            CustomTextfield(text: $value, placeHolder: "Your value", keyboardType: .numberPad)
        }
    }
}

---

以下选项使自定义文本字段可操作。。。对于更新外部绑定，希望这就是这么长描述的目标

使用Xcode 11.4/iOS 13.4进行测试

末尾的小

TestCustomTextfield

用于检查

CustomTextfield

中更改的更新标签

struct CustomTextfield: UIViewRepresentable {

    @Binding var text : String
    var placeHolder: String
    var keyboardType: UIKeyboardType

    final class Coordinator: NSObject, UITextFieldDelegate {

        var parent: CustomTextfield

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

        func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
            parent.text = textField.text ?? ""
            return true
        }
    }

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

    func makeUIView(context: Context) -> UITextField {

        let textField = UITextField()
        textField.backgroundColor = .white
        textField.placeholder = self.placeHolder
        textField.keyboardType = self.keyboardType
        textField.setContentHuggingPriority(.required, for: .vertical)
        textField.delegate = context.coordinator

        return textField
    }

    func updateUIView(_ uiField: UITextField, context: Context) {
        if let text = textField.text as NSString? {
           parent.text = text.replacingCharacters(in: range, with: string)
        } else {
           parent.text = ""
        }
     }

}

struct TestCustomTextfield: View {
    @State private var value = ""
    var body: some View {
        VStack {
            Text("Label: \(value)")
            CustomTextfield(text: $value, placeHolder: "Your value", keyboardType: .numberPad)
        }
    }
}

---

您好，我已经添加了一行，以便在每次启动委托方法时打印字段的值，但由于某些原因，第一次启动时，该值为空，第二次启动时，它显示了应该在第一次启动时显示的值，依此类推。我在“return true”行之前加了一行。@LondonGuy，修正了这个问题。这让我找到了答案。updateUIView中的代码位于错误的位置。您好，我添加了一行，以便在每次启动委托方法时打印字段的值，但由于某些原因，第一次启动时，该值为空，第二次启动时，它显示了第一次启动时应显示的值，依此类推。我在“return true”行之前加了一行。@LondonGuy，修正了这个问题。这让我找到了答案。updateUIView中的代码位于错误的位置。