SwiftUI封装macOS NSSearchField输入文字过长时滚动失效、光标卡滞问题

macOS 11 版本下SwiftUI未原生提供搜索组件，封装NSSearchField后出现文本超出输入框宽度时无法自动横向滚动、光标无法移动到可视范围外的问题，和原生TextField的对比如下：

• updateNSView 方法更新逻辑不合理：每次绑定的text值变化时直接全量覆盖NSSearchField的stringValue，会强制重置输入框内部的光标位置、文本滚动偏移，打断原生的自动滚动逻辑
• 初始化NSSearchField时未显式开启文本横向滚动配置

import SwiftUI

struct SearchBar: NSViewRepresentable {
    private var placeholder: String
    @Binding var text: String
    
    init(_ placeholder: String, text: Binding<String>) {
        self.placeholder = placeholder
        _text = text
    }
    
    class Coordinator: NSObject, NSSearchFieldDelegate {
        @Binding var text: String
        init(text: Binding<String>) {
            _text = text
        }
        
        func controlTextDidChange(_ obj: Notification) {
            if let searchField = obj.object as? NSSearchField {
                text = searchField.stringValue
            }
        }
    }

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

    func makeNSView(context: NSViewRepresentableContext<SearchBar>) -> NSSearchField {
        let searchField = NSSearchField(frame: .zero)
        searchField.delegate = context.coordinator
        searchField.placeholderString = placeholder
        // 显式开启文本横向滚动、关闭自动换行
        searchField.cell?.wraps = false
        searchField.cell?.isScrollable = true
        return searchField
    }

    func updateNSView(_ nsView: NSSearchField, context: NSViewRepresentableContext<SearchBar>) {
        // 仅当外部绑定值与输入框当前内容不一致时才更新，避免打断输入状态
        guard nsView.stringValue != text else { return }
        nsView.stringValue = text
    }
}

struct SearchBar_Previews: PreviewProvider {
    @State private static var text = ""
    static var previews: some View {
        SearchBar("Search", text: $text)
    }
}

• 初始化NSSearchField时添加cell属性配置，开启文本横向滚动能力、关闭自动换行
• 优化updateNSView更新逻辑，仅在外部绑定值与输入框当前内容不同时才赋值，避免无意义的全量覆盖打断用户输入时的原生交互状态

内容的提问来源于stack exchange，提问作者Hamer