ios - for in 循环循环两次 Swift

Question

在我的 saveOrder() 函数(由 Firebase 观察者调用)中，我创建了一个新的 Order 实体条目并设置了一个 for in 循环。在循环中，我调用 decrementInventory() 修改 Product(它们之间没有关系)实体条目，并创建一个新的 Item 实体子项coreData 中的Order。我的问题是:当 decrementInventory() 被调用一次并正确完成工作时，我创建了两次 Item 记录。该循环基于 productIdListArray.count ，但是对于 1 的 count 循环两次等等。您能看出为什么要循环两次吗？一如既往地非常感谢。

这是函数，对于 iOS9 和 10 来说有点长:

static func saveOrder(completed: @escaping(Bool) ->(),state: String ,orderId: String, orderDate: String, customerId: String, customerName: String, customerFcmToken: String, orderPrice: String, itemsIdList: String, itemsList: String, itemsCategoryList: String, itemsPriceList: String, promotionList: String) throws {
        print("Order.saveOrder() : STARTED")

        let context = CoreData.databaseContext
        let userRequest: NSFetchRequest<User> = User.fetchRequest()
        do {
            let userFetch = try context.fetch(userRequest)
            print("Order.saveOrder() : fetching user")
            for userValue in userFetch {
                if userValue.name == UserDetails.fullName {
                    print("Order.saveOrder() : User is: \(userValue.name!)")
                    let orderRequest: NSFetchRequest<Order> = Order.fetchRequest()
                    let predicate = NSPredicate(format: "orderId == %@", orderId)
                    orderRequest.predicate = predicate
                    orderRequest.fetchLimit = 1
                    do {
                        let orderFetch = try context.fetch(orderRequest)
                        if orderFetch.count == 0 {

                            print("Order.saveOrder() : order is new")
                            if #available(iOS 10.0, *) {
                                let order = Order(context: context)
                                order.user?.name = userValue.name!
                                order.orderId = orderId
                                order.orderDate = orderDate
                                order.customerName = customerName
                                order.customerId = customerId
                                order.customerFcmToken = customerFcmToken
                                order.orderPrice = orderPrice
                                order.itemsIdList = itemsIdList
                                order.itemsList = itemsList
                                order.itemsCategoryList = itemsCategoryList
                                order.itemsPriceList = itemsPriceList
                                order.promotionList = promotionList
                                userValue.addToOrders(order)
                                print("Order.saveOrder() : Order is: \(order)")
                                let actions: [UNNotificationAction] = [UNNotificationAction(identifier: "chiudi", title: "Chiudi", options: [.foreground])]
                                LocalNotifications.newTimeIntervalNotification(notificationType: "New order", actions: actions, categoyIdentifier: "New order", title: "Ordine", body: "Hai un nuovo ordine", userInfo: [:] , timeInterval: 0.1, repeats: false)

                                var productIdListArray:[String] = itemsIdList.components(separatedBy: ",")
                                var productNameListArray:[String] = itemsList.components(separatedBy: ",")
                                var productCategoryListArray: [String] = itemsCategoryList.components(separatedBy: ",")
                                var productPriceListArray: [String] = itemsPriceList.components(separatedBy: ",")
                                print("productIdListArray.count is :  \(productIdListArray.count)")
                                var productPromotionListArray: [String] = promotionList.components(separatedBy: ",")
                                for product in 0..<productIdListArray.count {

                                    print("productIdListArray.count is : \(productIdListArray.count)")
                                    do {
                                        try Product.decrementIventory(completed: { (true) in
                                            let  item = Item(context: context)
                                            item.order?.orderId = orderId
                                            item.itemId = productIdListArray[product]
                                            item.itemName = productNameListArray[product]
                                            item.price = productPriceListArray[product]
                                            item.category = productCategoryListArray[product]
                                            item.promotion = productPromotionListArray[product]
                                            let fullDate = Conversions.dateConvert(dateString: order.orderDate!)! as NSDate
                                            print("Order.saveOrder() : fullDate is: \(fullDate)")
                                            item.date =  fullDate
                                            order.addToItems(item)
                                            print("Order.saveOrder() : New item record is: \(item)")
                                            print("Order.saveOrder: Inventory seccessfully updated for product: \(productNameListArray[product])")
                                        }, productId: productIdListArray[product])
                                    } catch {
                                        print("Order.saveOrder() : Error in decrementing inventory : \(error)")
                                    }
                                }
                            } else {
                                // Fallback on earlier versions
                                let entityDescription = NSEntityDescription.entity(forEntityName: "Order", in: context)
                                let order = Order(entity: entityDescription!, insertInto: context)
                                order.user?.name = userValue.name!
                                order.orderId = orderId
                                order.orderDate = orderDate
                                order.customerId = customerId
                                order.customerName = customerName
                                order.customerFcmToken = customerFcmToken
                                order.orderPrice = orderPrice
                                order.itemsIdList = itemsIdList
                                order.itemsList = itemsList
                                order.itemsCategoryList = itemsCategoryList
                                order.itemsPriceList = itemsPriceList
                                order.promotionList = promotionList
                                userValue.addToOrders(order)
                                LocalNotifications.newTimeIntervalNotification(notificationType: "New order", actions: [], categoyIdentifier: "New order", title: "Ordine", body: "Hai un nuovo ordine", userInfo: [:], timeInterval: 0.1, repeats: false)
                                var productIdListArray:[String] = itemsIdList.components(separatedBy: ",")
                                var productNameListArray:[String] = itemsList.components(separatedBy: ",")
                                var productCategoryListArray: [String] = itemsCategoryList.components(separatedBy: ",")
                                var productPriceListArray: [String] = itemsPriceList.components(separatedBy: ",")
                                var productPromotionListArray: [String] = promotionList.components(separatedBy: ",")
                                for product in 0..<productIdListArray.count {
                                    do {
                                        try Product.decrementIventory(completed: { (true) in
//                                            let entityDescription = NSEntityDescription.entity(forEntityName: "Item", in: context)
                                            let item = Item(entity: entityDescription!, insertInto: context)

//                                            item.order?.user?.name = userValue.name!
                                            item.order?.orderId = orderId
                                            item.itemId = productIdListArray[product]
                                            item.itemName = productNameListArray[product]
                                            item.price = productPriceListArray[product]
                                            item.category = productCategoryListArray[product]
                                            item.promotion = productPromotionListArray[product]
                                            let fullDate = Conversions.dateConvert(dateString: order.orderDate!)! as NSDate
                                            print("Order.saveOrder() : fullDate is: \(fullDate)")
                                            item.date =  fullDate
                                            order.addToItems(item)
                                            print("Order.saveOrder() : New item record is: \(item)")
                                            print("Order.saveOrder: Inventory seccessfully updated for product: \(productNameListArray[product])")
                                        }, productId: productIdListArray[product])
                                    } catch {
                                        print("Order.saveOrder() : Error in decrementing inventory : \(error)")
                                    }
                                }
                            } // end of iOS 9

                        } else {
                            print("Order.saveOrder() : Order is already saved")
                            return
                        }
                    } catch {
                        print("Order.saveOrder():Error in fetching orders: \(error)")
                    }
                }
            }
        } catch {
            print("Order.saveOrder() : Error in fetching user: \(error)")
        }
        do {
            try context.save()
            print("Order.saveOrder():   New order is saved do CoreData")
            completed(true)
        } catch  {
            print(" Order.saveOrder():  Error saving new order to CoreData: \(error)")
        }
        print("Order.saveOrder() : ENDED")
    }

这是 Firebase 观察器:

static func getOrders(completed: @escaping (Bool) -> ()) {
        print("getOrders() : started")

        let ref = Database.database().reference()

        // .childAdded
        ref.child("Continent").child("Europe").child("Country").child("\(UserDetails.country!)").child("Region").child(UserDetails.region!).child("City").child(UserDetails.city!).child("Shops").child(UserDetails.fullName!).child("Orders").observe(.childAdded) { (snapshot) in
            print("snapshot is: \(snapshot)")
            guard let value = snapshot.value as? [String : String] else {return}
            let orderId = value["Order Id"]!
            let orderDate = value["Order Date"]!
            let customerId = value["User Id"]!
            let customerName = value["User Name"]!
            let customerFcmToken = value["User fcmToken"]!
            let orderPrice = value["Order Price"]!
            let itemsIdList = value["Items Id List"]!
            let itemsList = value["Items List"]!
            let itemsCategoryList = value["Items Category List"]!
            let itemsPriceList = value["Items Price List"]!
            let itemsPromotionList = value["Items Promotion List"]!

            do {
                try Order.saveOrder(completed: { (true) in
                    print("getOrders(): order saved to CoreData")
                    // send push to customer
                    PushNotifications.sendPushNotification(to: customerFcmToken, title: "Order number: \(String(describing: orderId))", subtitle: " Shop: \(String(describing: UserDetails.fullName!))", body: "Thank you \(customerName)! We received your order and we'll let you know when we start preparing it and when it's ready. Bye ")
                    // localize push
//                    PushNotifications.sendPushNotification(to: customerFcmToken, title: NSLocalizedString(String(format: "Order number: %1@", orderId), comment: ""), subtitle: NSLocalizedString(String(format: "Shop: %1@", UserDetails.fullName!), comment: ""), body: String(format: "Thank you %1@! We received your order and we'll let you know when we start preparing it and when it's ready. Bye ", customerName))


                }, state: "received", orderId: orderId, orderDate: orderDate, customerId: customerId, customerName: customerName, customerFcmToken: customerFcmToken, orderPrice: orderPrice,itemsIdList: itemsIdList, itemsList: itemsList, itemsCategoryList: itemsCategoryList, itemsPriceList: itemsPriceList, promotionList: itemsPromotionList)
                print("getOrders() : ended, now observing")
                completed(true)
            } catch {
                print("getOrders(): Error in saving snapshot to Core Data : \(error)")
            }
        }
    }

Answer 1

经过相当多的尝试，我发现我错误地调用了两次 decrementInventory() 的完成，这实际上是 的 for in 循环的开始保存订单()。希望这会帮助其他人。干杯