如何通过单击键盘上的返回按钮来浏览 SwiftUI 文本字段？

Question

我正在使用 SwiftUI 的 TextField View。主要是我有2个问题：

1. 在 Swift 中，我们可以像这样为 Storyboard 中的 TextField 设置 Return Key(Text Input Traits) 为 Next 对吧？为此在 SwiftUI 中使用哪个修饰符？
   
   
   

2. 我有两个文本字段，当我从键盘单击返回/下一个按钮时，如何导航到下一个文本字段？

任何人都可以使用 SwiftUI（不是 UIKit）来帮助解决这个问题吗？或者任何其他替代方法来执行此功能？

Answer 1

要解决您的两个问题，您需要使用 SwiftUI 中的 UIKit。首先，您需要使用 UIViewRepresentable 自定义 TextField。这是用于测试目的的示例代码，尽管代码不是那么优雅。我敢打赌，会有更强大的解决方案。

1. 在自定义的TextFieldType中，键盘返回类型有 被设置。
2. 通过使用对象绑定和委托方法 textFieldShouldReturn，View可以通过更新绑定变量来聚焦键盘。

这里是示例代码：

import SwiftUI

struct KeyboardTypeView: View {
    @State var firstName = ""
    @State var lastName = ""
    @State var focused: [Bool] = [true, false]

    var body: some View {
        Form {
            Section(header: Text("Your Info")) {
                TextFieldTyped(keyboardType: .default, returnVal: .next, tag: 0, text: self.$firstName, isfocusAble: self.$focused)
                TextFieldTyped(keyboardType: .default, returnVal: .done, tag: 1, text: self.$lastName, isfocusAble: self.$focused)
                Text("Full Name :" + self.firstName + " " + self.lastName)
            }
        }
}
}



struct TextFieldTyped: UIViewRepresentable {
    let keyboardType: UIKeyboardType
    let returnVal: UIReturnKeyType
    let tag: Int
    @Binding var text: String
    @Binding var isfocusAble: [Bool]

    func makeUIView(context: Context) -> UITextField {
        let textField = UITextField(frame: .zero)
        textField.keyboardType = self.keyboardType
        textField.returnKeyType = self.returnVal
        textField.tag = self.tag
        textField.delegate = context.coordinator
        textField.autocorrectionType = .no

        return textField
    }

    func updateUIView(_ uiView: UITextField, context: Context) {
        if isfocusAble[tag] {
            uiView.becomeFirstResponder()
        } else {
            uiView.resignFirstResponder()
        }
    }

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

    class Coordinator: NSObject, UITextFieldDelegate {
        var parent: TextFieldTyped

        init(_ textField: TextFieldTyped) {
            self.parent = textField
        }

        func updatefocus(textfield: UITextField) {
            textfield.becomeFirstResponder()
        }

func textFieldShouldReturn(_ textField: UITextField) -> Bool {

            if parent.tag == 0 {
                parent.isfocusAble = [false, true]
                parent.text = textField.text ?? ""
            } else if parent.tag == 1 {
                parent.isfocusAble = [false, false]
                parent.text = textField.text ?? ""
         }
        return true
        }

    }
}

输出：

Answer 2

截至 2021 年 6 月 15 日，它仍处于测试阶段。

---

iOS 15.0+

macOS 12.0+， Mac 催化剂 15.0+， tvOS 15.0+, watchOS 8.0+

使用为视图设置提交标签的submitLabel(_:) 视图修饰符。它采用SubmitLabel中指定的预定义大小写

使用.next。它定义了一个带有 “Next” 文本的提交标签。

使用onFocus(_:) 查找修改后的视图层次结构（在本例中为TextField）失去焦点的时间。完成后，将焦点放在下一个视图上 (SecureField)

struct LoginForm: View {
    enum Field: Hashable {
        case usernameField
        case passwordField
    }
    
    @State private var username = ""
    @State private var password = ""
    @FocusState private var focusedField: Field?
    
    var body: some View {
        Form {
            TextField("Username", text: $username)
                .focused($focusedField, equals: .usernameField)
                .submitLabel(.next)
                .onFocus { isFocused in
                    if (!isFocused) {
                        focusedField = .passwordField
                    }
                }
            
            SecureField("Password", text: $password)
                .focused($focusedField, equals: .passwordField)
                .submitLabel(.done)
        }
    }
}

• submitLabel(_:)
• SubmitLabel
• .next
• onfocus(_:)

---

更新

我在xCode version 13.0 beta 5 (13A5212g) 中对此进行了测试。它有效。

Answer 3

你不能，SwiftUI 中还没有响应者链的概念。您不能以编程方式启动对任何 View 的关注，因为它们实际上并不是视图本身，只是描述应如何设置视图的结构。我猜它最终可能会通过EnvironmentValues 暴露（如截断、自动更正等），但目前不存在。

Answer 4

根据 Razib Mollick 的回答和 https://www.hackingwithswift.com/forums/100-days-of-swiftui/jump-focus-between-a-series-of-textfields-pin-code-style-entry-widget/765

我为文本字段数组提出了以下实现。

struct NextLineTextField: UIViewRepresentable {
@Binding var text: String
@Binding var selectedField: Int

var tag: Int
var keyboardType: UIKeyboardType = .asciiCapable
var returnKey: UIReturnKeyType = .next

func makeUIView(context: UIViewRepresentableContext<NextLineTextField>) -> UITextField {
    let textField = UITextField(frame: .zero)
    textField.delegate = context.coordinator
    textField.keyboardType = keyboardType
    textField.returnKeyType = returnKey
    textField.tag = tag
    return textField
}

func makeCoordinator() -> NextLineTextField.Coordinator {
    return Coordinator(text: $text)
}

func updateUIView(_ uiView: UITextField, context: UIViewRepresentableContext<NextLineTextField>) {
    uiView.text = text
    context.coordinator.newSelection = { newSelection in
        DispatchQueue.main.async {
            self.selectedField = newSelection
        }
    }

    if uiView.tag == self.selectedField {
        uiView.becomeFirstResponder()
    }
}

class Coordinator: NSObject, UITextFieldDelegate {

    @Binding var text: String
    var newSelection: (Int) -> () = { _ in }

    init(text: Binding<String>) {
        _text = text
    }

    func textFieldDidChangeSelection(_ textField: UITextField) {
        DispatchQueue.main.async {
            self.text = textField.text ?? ""
        }
    }
    
    func textFieldDidBeginEditing(_ textField: UITextField) {
        self.newSelection(textField.tag)
    }

    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        if textField.returnKeyType == .done {
            textField.resignFirstResponder()
        } else {
            self.newSelection(textField.tag + 1)
        }
        return true
    }
  }
}

然后将表单元素设为

class FieldElement: ObservableObject, Identifiable {
var id = UUID()
var title = ""
@Published var value = ""
var keyboard: UIKeyboardType = .asciiCapable
var returnType: UIReturnKeyType = .next

init(title: String, value: String = "", keyboard: UIKeyboardType = 
    .asciiCapable, returnType: UIReturnKeyType = .next) {
    self.title = title
    self.value = value
    self.keyboard = keyboard
    self.returnType = returnType
  }
}

为了实现

struct FormView: View {

@State var formElements: [FieldElement] = [
    FieldElement(title: "Name"),
    FieldElement(title: "Address"),
    FieldElement(title: "Phone Number"),
    FieldElement(title: "Email Address", keyboard: .emailAddress, returnType: 
.done),
]

@State var selectedField = 0

var body: some View {
    VStack(alignment: .leading) {
        ForEach(Array(zip(formElements.indices, formElements)), id: \.0) { 
        index, element in
            VStack(alignment: .leading, spacing: 0) {
                Text(element.title)

                NextLineTextField(text: self.$formElements[index].value,
                    selectedField: self.$selectedField,
                    tag: index,
                    keyboardType: element.keyboard,
                    returnKey: element.returnType)
                    .frame(height: 35)
                    .frame(maxWidth: .infinity)
                    .overlay(
                        RoundedRectangle(cornerRadius: 8)
                            .stroke(Color.gray.opacity(0.5), lineWidth: 0.7)
                    )
            }.padding(.bottom, 4)
        }

        Button(action: {
            print(self.formElements.map({ $0.value }))
        }) {
            Text("Print Entered Values")
                .foregroundColor(Color.white)
                .font(.body)
                .padding()
        }.frame(height: 50)
            .background(Color.green)
            .cornerRadius(8)
            .padding(.vertical, 10)
        Spacer()
    }.padding()
  }
}

如果这很难导航，请随时查看 https://github.com/prakshapan/Utilities/blob/master/FormView.swift