核心数据，嵌套列表

Question

我尝试在嵌套列表中使用从 Core Data 获取的数据，但是当我添加“children: .listofTasksArray”时，显示以下错误： “关键路径值类型'[ListOfTasks]？'无法转换为上下文类型 'FetchedResults?'” 这是核心数据文件

extension ListOfTasks {

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

    @NSManaged public var addedDate: Date?
    @NSManaged public var color: String?
    @NSManaged public var favoriteIndex: Int16
    @NSManaged public var icon: String?
    @NSManaged public var id: UUID?
    @NSManaged public var index: Int16
    @NSManaged public var isArchived: Bool
    @NSManaged public var isFavorite: Bool
    @NSManaged public var isLocked: Bool
    @NSManaged public var title: String?
    @NSManaged public var isList: Bool
    @NSManaged public var origin: ListOfTasks?
    @NSManaged public var subLists: NSSet?
    
    // The wrapped items
    public var wrappedAddedDate: Date {
        return addedDate ?? Date()
    }

    // To convert the color from "String" to "Color" type
    public var wrappedColor: Color {
        return Color(colorName: color ?? "blue")
    }
    
    public var wrappedIcon: String {
        return icon ?? "ellipsis.circle.fill"
    }
    
    public var wrappedId: UUID {
        return id ?? UUID()
    }
    
    public var wrappedTitle: String {
        return title ?? "Unknown Title"
    }
    
    public var listofTasksArray: [ListOfTasks]? {
        let set = subLists as? Set<ListOfTasks> ?? nil
        
        return set?.sorted { // sort by index
            [=10=].index > .index
        }
    }
}

这是我用来获取数据并在列表中使用它的列表代码，试图使用 ListOfTasks 属性“listofTasksArray”作为列表的子项来制作嵌套列表。

struct ListsView: View {

    @FetchRequest(entity: ListOfTasks.entity(), sortDescriptors: [NSSortDescriptor(keyPath: \ListOfTasks.index, ascending: true)], animation: .default) private var lists: FetchedResults<ListOfTasks>

var body: some View {

    List(lists, children: \.listofTasksArray, rowContent: { Text([=11=].wrappedTitle) })

}
}

Answer 1

数据容器的类型应该是相同的，所以尝试将 FetchedResults 包装到一个数组中，例如（可能需要对可选值进行一些调整）

var body: some View {
    List(Array(lists), children: \.listofTasksArray) { 
       Text([=10=].wrappedTitle
    }
}

核心数据，嵌套列表

Core Data, Nested List

swift

core-data

swiftui

swiftui-list