Swift 3- Actualizar la interfaz de usuario desde el hilo principal

Quería cargar datos en el hilo de fondo y actualizar tableview / UI en el hilo principal. Basado en lo que se indicaaquí sobre el enhebrado, me preguntaba si el siguiente código es la forma de hacerlo. Estoy tratando de cargar más datos a medida que el usuario se desplaza a un índice específico y quería asegurarme de que la interfaz de usuario no se congele debido a subprocesos. ¡Gracias!

 func loadMore () {
    guard !self.reachedEndOfItems else {
        return
    }

    self.offset = self.offset! + 10
    print("load more offset: \(self.offset)")

    var start = 0
    var end = 0


    isPullToRefresh = false

    let userCreds = UserDefaults.standard

    var getReqString = ""


    if userCreds.bool(forKey: "client_journal") == true || userCreds.bool(forKey: "user_journal") == true {

        var pageNum = ""
        if let pgNum = currentPgNum {
            print(pgNum)
            pageNum = String(pgNum)
        }
        var filterEntryType = ""
        if let entryTypeStr = filtEntryType {
            filterEntryType = entryTypeStr
        }

        var filterUserId = ""
        if let userId = filtUserId {
            filterUserId = userId

        }

        getReqString = "https://gethealthie.com/selected_entries.json?page=\(pageNum)&user_id=\(filterUserId)&entry_type=\(filterEntryType)&entry_filter="


    } else {

        if let pgNum = currentPgNum {
            print(pgNum)

            getReqString = "https://gethealthie.com/entries.json?page=\(pgNum)"
        }

    }


        BXProgressHUD.showHUDAddedTo(self.view)
        let request = Alamofire.request(getReqString, method: .get, headers: [
            "access-token": userCreds.object(forKey: "access-token")! as! String,
            "client": userCreds.object(forKey: "client")! as! String,
            "token-type": userCreds.object(forKey: "token-type")! as! String,
            "uid": userCreds.object(forKey: "uid")! as! String,
            "expiry": userCreds.object(forKey: "expiry")! as! String
            ]).responseJSON { (response:DataResponse<Any>) in
                print(response.response)

                let json = JSON(data: response.data!)
                print(json)

                print("yes")
                print(json.count)


                if userCreds.bool(forKey: "client_journal") == true || userCreds.bool(forKey: "user_journal") == true {
                    self.totalEntries = json["entries"].count

                    let totalEntryCount = json["entries"].count
                    start = 0
                    end = totalEntryCount
                } else {
                    self.totalEntries = json["entries"].count

                    let totalEntryCount = json["entries"].count
                    start = 0
                    end = totalEntryCount
                }

                if  self.totalEntries == 0 {
                    BXProgressHUD.hideHUDForView(self.view);

                } else if end <= self.totalEntries {
                    var jourIdx = 0

                    let newPatient = Patient()
                    let newDietitian = Dietitian()


                    for i in start ..< end {


                        let allEntries = json["entries"]
                        print(allEntries)
                        print("Entry count in loadMore is \(allEntries.count)")

                        let entry = allEntries[i]
                        print(entry)

                        let category = entry["category"]
                        print(category)


                        let name = entry["entry_comments"]
                        let k = name["id"]


                        var indexStr = String(i)

                        //entry attributes
                        self.jsonIdx.add(indexStr)

                        self.type.add(entry["type"].stringValue)
                        self.desc.add(entry["description"].stringValue)
                        self.category.add(entry["category"].stringValue)
                        //food cell- metric stat == healthy int
                        self.metric_stat.add(entry["metric_stat"].stringValue)
                        self.dateCreate.add(entry["created_at"].stringValue)
                        self.viewed.add(entry["viewed"].stringValue)
                        self.seenStatusArr.add(entry["viewed"].stringValue)
                        self.comments.add(entry["entry_comments"].rawValue)
                        self.entryType.add(entry["category"].stringValue)
                        //   "category" : entryType as AnyObject]

                        let posterInfo = entry["poster"]
                        let first = posterInfo["first_name"].stringValue
                        let last = posterInfo["last_name"].stringValue
                        let full = first + " " + last
                        self.captionName.add(full)


                        //food cell subcat
                        self.hungerInt.add(entry["percieved_hungriness"].stringValue)
                        self.prehunger.add(entry["ed_prehunger_string"].stringValue)
                        self.posthunger.add(entry["ed_posthunger_string"].stringValue)
                        self.emotions.add(entry["emotions_string"].stringValue)
                        self.reflection.add(entry["reflection"].stringValue)


                        print(self.comments)
                        self.id.add(entry["id"].stringValue)
                        self.entryImages.add(entry["image_url"].stringValue)


                        if i == end - 1 {
                            userCreds.set(json.count, forKey: "oldJsonCount")

                               BXProgressHUD.hideHUDForView(self.view)

                            DispatchQueue.main.async {
                                self.tableView.reloadData()

                            }
                    }


                } else {
                    var reachedEndOfItems = true
                    BXProgressHUD.hideHUDForView(self.view);
                    print("reached the end")
                }

    }

Respuestas a la pregunta(1)

Su respuesta a la pregunta