Question

        let bgContext = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)

        let moc = appDelegate.coreData.persistentContainer.viewContext
        bgContext.parent = moc
        bgContext.perform({

            let fetchedResultController: NSFetchedResultsController<ReservationsEntity>
            let request: NSFetchRequest<ReservationsEntity> = ReservationsEntity.fetchRequest()
            let sort = NSSortDescriptor(key: #keyPath(ReservationsEntity.reservedDate), ascending: true)
            request.sortDescriptors = [sort]
            request.predicate = NSPredicate(format: "isSynced == %@", NSNumber(value: false))
            fetchedResultController = NSFetchedResultsController(fetchRequest: request, managedObjectContext: moc, sectionNameKeyPath: nil, cacheName: nil)

            do{
                try fetchedResultController.performFetch()
                for reservationEntity in fetchedResultController.fetchedObjects!{

                    print(reservationEntity.isSynced!)
                    let params = BaseViewController.getReservationDictionaryForOffline(reservation: reservationEntity)
                    ServerCalls.addReservationToServer(parametersForReservation: params, kindOfScreen: 0, completionHandler: { (response) in
                        print(reservationEntity.isSynced!)

                        reservationEntity.isSynced = true

                    })
                }

            } catch{

            }


        })

问题：您好！我有一个用例AddReservation，其中我将一条记录添加到名为ReservationsEntity的CoreData Entity，其属性为isSynced到{{ 1}}最初。我也同时进行服务器调用，一旦服务器调用返回，我试图将标志false更新为isSynced。但在服务器调用返回后，我的CoreData对象变为零。

根据上面发布的代码，首先true在调试器中显示print(reservationEntity.isSynced!)。当我在false返回后尝试打印/访问reservationEntity时，应用会因ServerCalls.addReservationToServer对象变为reservationEntity而崩溃。

过去几天我一直试图修复它，尝试不同的方式，但没有用。我在这做什么错？

Answer 1

你能试试这段代码吗？

let bgContext = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
bgContext.persistentStoreCoordinator = appDelegate.coreData.persistentContainer.persistentStoreCoordinator

并删除

let moc = appDelegate.coreData.persistentContainer.viewContext
bgContext.parent = moc

当尝试在完成处理程序 - Swift4中更新时，CoreData获取的对象变为nil

1 个答案: