无法转换类型的返回表达式＆＃x27; fetchedResults＆lt;＆gt;＆＃x27;返回类型＆＃x27; [string]＆＃x27;

Question

我正在尝试通过存储在核心数据中的名称的书签列表中进行搜索，但是我在var SearchResults中的“返回项目”旁边遇到此错误

“无法将'fetty'fetchedResults＆lt; mybookmark的返回表达式转换为返回类型'[字符串]”“

 @FetchRequest(sortDescriptors: [NSSortDescriptor(keyPath: \MyBookmark.name, ascending: true)], animation: .default)
 private var items: FetchedResults<MyBookmark>
 @State private var searchText = ""

         ForEach(searchResults, id: \.self) { myBookmark in                        
                    Text(myBookmark.name!)
                    Text(myBookmark.url!)
                   }
                   .searchable(text: $searchText)




         var searchResults: [String] {
            if searchText.isEmpty {
               return items
          } else {
              return items.filter { $0.localizedCaseInsensitiveContains(searchText) }
            }
         }

mybookmark

@objc(MyBookmark)
public class MyBookmark: NSManagedObject, BaseModel {
    static var all: NSFetchRequest<MyBookmark> {
        let request: NSFetchRequest<MyBookmark> = MyBookmark.fetchRequest()
        request.sortDescriptors = []
        return request
    }
    
}


extension MyBookmark {

    @nonobjc public class func fetchRequest() -> NSFetchRequest<MyBookmark> {
        return NSFetchRequest<MyBookmark>(entityName: "MyBookmark")
    }

    @NSManaged public var name: String?
    @NSManaged public var url: String?

}

extension MyBookmark : Identifiable {

}

这是Macos应用程序

Answer 1

当搜索过滤器更改时，您需要再次执行提取请求。为此，您需要设置获取请求的谓词。

添加一个新属性来处理此问题

var query: Binding<String> {
    Binding {
        searchText
    } set: { newValue in
        searchText = newValue
        if newValue.isEmpty {
            items.nsPredicate = NSPredicate(value: true)
        } else {
            items.nsPredicate = NSPredicate(format: "name CONTAINS[cd] %@", newValue)            }
    }
}

然后将 .searchable 修饰符与该属性一起使用

var body: some View {
    ForEach {
        //...
    }
    .searchable(text: query)
}

Answer 2

该 var 必须返回一个 String 数组，但您返回的是 items 数组，它是一个 MyBookmark 类型的数组。

解决方案：将数组转换为[String]类型。

将该变量替换为：

         var searchResults: [String] {
            if searchText.isEmpty {
               return items.compactMap { $0.name }
          } else {
              return items.compactMap { $0.name }.filter { $0.localizedCaseInsensitiveContains(searchText) }
            }
         }