如何使用Swift在NSOutlineView中搜索字符串

// 定义一个结构体来表示NSOutlineView的项
struct Item {
    var name: String
    var children: [Item]
}

// 创建一个NSOutlineView的数据源
class OutlineViewDataSource: NSObject, NSOutlineViewDataSource {
    var items: [Item] = [] // NSOutlineView的项数据
    
    // 实现outlineView(_:isItemExpandable:)方法
    func outlineView(_ outlineView: NSOutlineView, isItemExpandable item: Any) -> Bool {
        if let item = item as? Item {
            return !item.children.isEmpty
        }
        return false
    }
    
    // 实现outlineView(_:child:ofItem:)方法
    func outlineView(_ outlineView: NSOutlineView, child index: Int, ofItem item: Any?) -> Any {
        if let item = item as? Item {
            return item.children[index]
        }
        return items[index]
    }
    
    // 实现outlineView(_:objectValueFor:byItem:)方法
    func outlineView(_ outlineView: NSOutlineView, objectValueFor tableColumn: NSTableColumn?, byItem item: Any?) -> Any? {
        if let item = item as? Item {
            return item.name
        }
        return nil
    }
}

// 创建一个NSOutlineView的代理
class OutlineViewDelegate: NSObject, NSOutlineViewDelegate {
    // 实现其他需要的代理方法
}

// 创建一个ViewController来管理NSOutlineView
class ViewController: NSViewController {
    @IBOutlet weak var outlineView: NSOutlineView!
    @IBOutlet weak var searchField: NSSearchField!
    
    let dataSource = OutlineViewDataSource()
    let delegate = OutlineViewDelegate()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 设置NSOutlineView的数据源和代理
        outlineView.dataSource = dataSource
        outlineView.delegate = delegate
        
        // 初始化NSOutlineView的项数据
        let item1 = Item(name: "Item 1", children: [])
        let item2 = Item(name: "Item 2", children: [])
        let item3 = Item(name: "Item 3", children: [])
        let item4 = Item(name: "Item 4", children: [])
        let item5 = Item(name: "Item 5", children: [])
        dataSource.items = [item1, item2, item3, item4, item5]
        
        // 监听搜索框的输入变化事件
        searchField.target = self
        searchField.action = #selector(searchFieldDidChange(_:))
    }
    
    @objc func searchFieldDidChange(_ sender: NSSearchField) {
        let keyword = sender.stringValue.lowercased()
        
        // 遍历NSOutlineView的所有项，执行搜索操作
        for item in dataSource.items {
            searchItem(item, keyword: keyword)
        }
        
        // 更新NSOutlineView的显示
        outlineView.reloadData()
    }
    
    func searchItem(_ item: Item, keyword: String) {
        var hasMatch = false
        
        // 比较项的显示值与搜索关键字是否匹配
        if item.name.lowercased().contains(keyword) {
            hasMatch = true
        }
        
        // 递归搜索子项
        for child in item.children {
            if searchItem(child, keyword: keyword) {
                hasMatch = true
            }
        }
        
        // 标记项为搜索结果或非搜索结果
        item.isSearchResult = hasMatch
    }
}