如何解决CoreData 未与 SwiftUI 中的列表视图同步？

我正在努力学习如何使用 Core Data 并使用 @State 让它强制同步视图。基本上我正在尝试创建一个简单的应用程序来了解它是如何协同工作的。我可以将一个新项目添加到 Core Data 中，但不知何故视图没有实时更新项目列表，我必须停止预览，然后重新构建我的新项目以显示在列表中。>

有人可以看看我的代码看看有什么问题吗？

我已将代码分成 4 个文件：

import Foundation
import CoreData
import UIKit

class CoreDataStorage {
    
    lazy var persistentContainer: NSPersistentContainer = {
            let container = NSPersistentContainer(name: "StoriesFromFallacya")
            container.loadPersistentStores { description,error in
                if let error = error {
                    fatalError("Unable to load persistent stores: \(error)")
                }
            }
            return container
        }()
    
    var context: NSManagedobjectContext {
      return  persistentContainer.viewContext
    }
    
    func fetchTaskList() -> [Dump] {
        
        let dumpList: [Dump]
        let fetchRequest: NSFetchRequest<CDDump> = CDDump.fetchRequest()
        if let rawDumPlist = try? context.fetch(fetchRequest){
            dumpList = rawDumPlist.compactMap({(rawDump:CDDump) -> Dump? in
                Dump(fromCoreDataObject: rawDump)
            })
        }else {
            dumpList = []
        }
        return dumpList
    }
    
    
    func addNewDump(dump: Dump){
        let newDump = CDDump(context: context)
        newDump.id = dump.id
        newDump.name = dump.name
        saveData()
    }
    
  
    
     func fetchCDDump(withId dumpId: UUID) -> CDDump?{
        let fetchRequest: NSFetchRequest<CDDump> = CDDump.fetchRequest()
        fetchRequest.predicate = nspredicate(format: "id == %@",dumpId as CVararg)
        fetchRequest.fetchLimit = 1
        let fetchResult = try? context.fetch(fetchRequest)
        return fetchResult?.first
    }
    
    
    private func saveData(){
        if context.hasChanges {
            do {
                try context.save()
                
            }catch {
                print("Erreur pendant la sauvegarde CoreData: \(error)")
            }
        }
    }
    
    
    
    func deleteDump(dumpID:UUID){
        if let dumpFound = fetchCDDump(withId: dumpID){
            self.context.delete(dumpFound)
            saveData()
        }else {
            print("Pas trouvé")
        }
    }
}

extension Dump {
    init?(fromCoreDataObject coreDataObject: CDDump){
        guard let id = coreDataObject.id,let name = coreDataObject.name else {
            return nil
        }
        self.id = id
        self.name = name
     
    }
}

2. 转储管理器

import Foundation
import SwiftUI

class DumpManager: ObservableObject {
    
    let storage: CoreDataStorage = CoreDataStorage()
    
   @Published var dumpList: [Dump] 
    
    init(){
        dumpList = storage.fetchTaskList()
    }

    @discardableResult
     func addDump(dumpName: String) -> Dump {
        let newDump = Dump(name: dumpName)
        dumpList.append(newDump)
        storage.addNewDump(dump: newDump)
        return newDump
    }
    
     func deleteDump(withID dumpID:UUID) {
        if let indexDump = dumpList.firstIndex(where: {
            (dump) -> Bool in
            dump.id == dumpID
        }) {
            dumpList.remove(at: indexDump)
            storage.deleteDump(dumpID: dumpID)
        }
    }
  
}

3. BrainDumpView

import SwiftUI
import CoreData

struct BrainDumpView: View {

   
//    @Observedobject var dumpManager: DumpManager = DumpManager()
    @State var theFuckingList = DumpManager().dumpList
    @State var taskManager = DumpManager()
   
 
    
    @State private var showingAddDumpView: Bool = false
//    @State var newDumpName: String
    
    var body: some View {
        NavigationView {
            vstack {
                vstack(alignment: HorizontalAlignment.leading){
                List{
                    ForEach(taskManager.dumpList) { dump in
                    Text(dump.name)
                }
                .onDelete(perform: deleteDump)
                .onTapGesture {
                    updateDump()
                }
            }
                Spacer()
        }
            }
            .navigationBarTitle(Text("Brain Dumps"))
            .navigationBarItems(trailing:
              Button(action:
                showingAddDump
            ) {
                Image(systemName: "plus")
                    .font(.largeTitle)
            }
            )
            }
       
        .sheet(isPresented: $showingAddDumpView,content: {
            NewDumpView(newDumpName: "",dumpList: $taskManager.dumpList)

                            })
       
    }
    func showingAddDump() {
        showingAddDumpView.toggle()
    }
//    func createNewDump() {
//        if newDumpName.count > 0 {
//            dumpManager.addDump(dumpName: newDumpName)
//        }
//        newDumpName = ""
//    }
    
    func deleteDump(offsets: IndexSet){
        taskManager.deleteDump(withID: taskManager.dumpList[offsets[offsets.startIndex]].id)
        }
    }

func updateDump(){
    
}

struct BrainDumpView_Previews: PreviewProvider {
 
    
    static var previews: some View {
        
      
        BrainDumpView()
    }
}

4. 新建转储视图

import SwiftUI

struct NewDumpView: View {
    
  
    @Environment(\.presentationMode) var presentationMode
    @Observedobject var dumpManager: DumpManager = DumpManager()
    @State var taskManager = DumpManager()
    @State var newDumpName: String
    @Binding var dumpList: [Dump]
  
    var body: some View {
        NavigationView {
            vstack{
                Spacer()
                TextField("Dump",text: $newDumpName,onCommit: createNewDump)
                    
                    .padding()
                    .background(Color(UIColor.tertiarySystemFill))
                    .cornerRadius(9)
                    .font(.system(size: 24,weight: .bold,design: .default))
                    .navigationBarTitle("New Dump",displayMode: .inline)
                    .navigationBarItems(trailing:
                      Button(action: {
                        self.presentationMode.wrappedValue.dismiss()
                    }) {
                        Image(systemName: "xmark")
                    }
                    )
           
                Button(action: {
                               self.presentationMode.wrappedValue.dismiss()
                    createNewDump()
                             }) {
                               Text("Save")
                             }
            }
            
        }
        .padding()
                .navigationViewStyle(StackNavigationViewStyle())
                                    }
    
    func createNewDump() {
        if newDumpName.count > 0 {
            
            taskManager.addDump(dumpName: newDumpName)
        }
        newDumpName = ""
        self.presentationMode.wrappedValue.dismiss()
    }
                                    
}

非常感谢，我已经为此苦苦挣扎了好几天了：/

解决方法

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