Items retain in List after deleting in CoreData

Question

Created Apr ’21

Replies 1

Boosts 0

Participants 1

I don't understand when I try to remove all items by calling viewContext.execute(deleteRequest) SwiftUI doesn't redraw UI. I see items from sqlite are gone.

Code Block swiftstruct CloudKitTestView: View {
    @Environment(\.managedObjectContext) private var viewContext
    @FetchRequest(
        sortDescriptors: [NSSortDescriptor(keyPath: \Item.timestamp, ascending: true)],
        animation: .default)
    private var items: FetchedResults<Item>
    var body: some View {
        VStack {
            Button("Remove all") {
                let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "Item")
                let deleteRequest = NSBatchDeleteRequest(fetchRequest: fetchRequest)
                do {
                    try viewContext.execute(deleteRequest)
                } catch {
                    // Replace this implementation with code to handle the error appropriately.
                    // fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
                    let nsError = error as NSError
                    fatalError("Unresolved error \(nsError), \(nsError.userInfo)")
                }
            }
            List {
                ForEach(items) { item in
                    Text("Item at \(item.timestamp!, formatter: itemFormatter)")
                }
                .onDelete(perform: deleteItems)
            }
            .toolbar {
                #if os(iOS)
                EditButton()
                #endif
                Button(action: addItem) {
                    Label("Add Item", systemImage: "plus")
                }
            }
        }
    }
    private func addItem() {
        withAnimation {
            let newItem = Item(context: viewContext)
            newItem.timestamp = Date()
            do {
                try viewContext.save()
            } catch {
                // Replace this implementation with code to handle the error appropriately.
                // fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
                let nsError = error as NSError
                fatalError("Unresolved error \(nsError), \(nsError.userInfo)")
            }
        }
    }
    private func deleteItems(offsets: IndexSet) {
        withAnimation {
            offsets.map { items[$0] }.forEach(viewContext.delete)
            do {
                try viewContext.save()
            } catch {
                // Replace this implementation with code to handle the error appropriately.
                // fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
                let nsError = error as NSError
                fatalError("Unresolved error \(nsError), \(nsError.userInfo)")
            }
        }
    }
}

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Answer 1

filimo OP

Apr ’21

There is an issue when I try to update List. CoreData is updated but List shows old value.

Code Block swiftlet request = NSBatchUpdateRequest(entity: Item.entity())
request.propertiesToUpdate = ["timestamp": Date()]
do {
    try viewContext.execute(request)
} catch {
    let nsError = error as NSError
    fatalError("Unresolved error \(nsError), \(nsError.userInfo)")
}

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