单击 SwiftUI 时选择 TextField 中的所有文本

Question

在文本字段内单击时如何选择所有文本？就像在 Chrome 等网络浏览器中单击地址栏时的情况一样。

import SwiftUI
import AppKit

   struct ContentView: View {

    var body: some View {
        TextField("Enter a URL", text: $site)
    
  }
}

Answer 1

SwiftUI 解决方案：

struct ContentView: View {
    var body: some View {
        TextField("Placeholder", text: .constant("This is text data"))
            .onReceive(NotificationCenter.default.publisher(for: UITextField.textDidBeginEditingNotification)) { obj in
                if let textField = obj.object as? UITextField {
                    textField.selectedTextRange = textField.textRange(from: textField.beginningOfDocument, to: textField.endOfDocument)
                }
            }
    }
}

注意：导入组合

使用委托UIViewRepresentable包装UITextField和使用属性。textField.selectedTextRange

这是示例演示

struct HighlightTextField: UIViewRepresentable {
    
    @Binding var text: String
    
    func makeUIView(context: Context) -> UITextField {
        let textField = UITextField()
        textField.delegate = context.coordinator
        return textField
    }
    
    func updateUIView(_ textField: UITextField, context: Context) {
        textField.text = text
    }
    
    func makeCoordinator() -> Coordinator {
        Coordinator(parent: self)
    }
    
    class Coordinator: NSObject, UITextFieldDelegate {
        var parent: HighlightTextField
        
        init(parent: HighlightTextField) {
            self.parent = parent
        }
        
        func textFieldDidBeginEditing(_ textField: UITextField) {
            textField.selectedTextRange = textField.textRange(from: textField.beginningOfDocument, to: textField.endOfDocument)
        }
    }
}

对于 macOS

struct HighlightTextField: NSViewRepresentable {
    
    @Binding var text: String
    
    func makeNSView(context: Context) -> CustomTextField {
        CustomTextField()
    }
    
    func updateNSView(_ textField: CustomTextField, context: Context) {
        textField.stringValue = text
    }
}

class CustomTextField: NSTextField {
    override func mouseDown(with event: NSEvent) {
        if let textEditor = currentEditor() {
            textEditor.selectAll(self)
        }
    }
}

Answer 2

我创建了一个ViewModifier来选择 a 中的所有文本TextField。唯一的缺点是，它不能与多个TextFields.

public struct SelectTextOnEditingModifier: ViewModifier {
    public func body(content: Content) -> some View {
        content
            .onReceive(NotificationCenter.default.publisher(for: UITextField.textDidBeginEditingNotification)) { obj in
                if let textField = obj.object as? UITextField {
                    textField.selectedTextRange = textField.textRange(from: textField.beginningOfDocument, to: textField.endOfDocument)
                }
            }
    }
}

extension View {

    /// Select all the text in a TextField when starting to edit.
    /// This will not work with multiple TextField's in a single view due to not able to match the selected TextField with underlying UITextField
    public func selectAllTextOnEditing() -> some View {
        modifier(SelectTextOnEditingModifier())
    }
}

用法：

TextField("Placeholder", text: .constant("This is text data"))
    .selectAllTextOnEditing()