将加载的json文件中的更改保存到SwiftUI中的核心数据

import SwiftUI
import CoreData

struct ContentView: View {
    @Environment(\.managedObjectContext) private var viewContext
    @FetchRequest(entity: YourEntity.entity(), sortDescriptors: []) var items: FetchedResults<YourEntity>

    var body: some View {
        // Your SwiftUI view code here
        // Display and edit the loaded JSON data using SwiftUI controls
        
        Button("Load JSON") {
            if let url = Bundle.main.url(forResource: "data", withExtension: "json") {
                do {
                    let data = try Data(contentsOf: url)
                    let decoder = JSONDecoder()
                    let decodedData = try decoder.decode([YourDecodableStruct].self, from: data)
                    
                    for item in decodedData {
                        // Check if the item already exists in the core data
                        let fetchRequest: NSFetchRequest<YourEntity> = YourEntity.fetchRequest()
                        fetchRequest.predicate = NSPredicate(format: "id == %@", item.id)
                        
                        if let existingItem = try viewContext.fetch(fetchRequest).first {
                            // Update the existing item
                            existingItem.name = item.name
                            // Update other properties as needed
                        } else {
                            // Create a new item
                            let newItem = YourEntity(context: viewContext)
                            newItem.id = item.id
                            newItem.name = item.name
                            // Set other properties as needed
                        }
                    }
                    
                    // Save the changes to the core data
                    try viewContext.save()
                } catch {
                    print("Error decoding JSON: \(error)")
                }
            }
        }
    }
}