Items retain in List after deleting in CoreData

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Created Apr ’21

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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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