ios - Why do I get nil in my Collection View Cell? -

i using alamofire in case when debug alamofire code not execute , tried manually creating url , setting headers , calling api url.

my collection view class follows.

// //  categoryviewcontroller.swift //  irate // //  created ammar khan on 16/08/2017. //  copyright © 2017 theistudio. rights reserved. //  import uikit import alamofire import swiftyjson import sdwebimage  class categoryviewcontroller: uiviewcontroller, uicollectionviewdatasource, uicollectionviewdelegate {     @iboutlet var mycollectionview: uicollectionview!     var catarr:[string] = []     var catimage:[string] = []      let categoriesurl = "http://127.0.0.1:8000/api/places/categories"      override func viewdidload() {         super.viewdidload()          // additional setup after loading view.     }      override func viewdidappear(_ animated: bool) {         loadcatlist()     }      override func didreceivememorywarning() {         super.didreceivememorywarning()         // dispose of resources can recreated.     }      func collectionview(_ collectionview: uicollectionview, numberofitemsinsection section: int) -> int {         return 2     }      func collectionview(_ collectionview: uicollectionview, cellforitemat indexpath: indexpath) -> uicollectionviewcell {         let cell = collectionview.dequeuereusablecell(withreuseidentifier: "cell", for:indexpath) as! categorycell         print("reached on here \(self.catarr.count)")         cell.categoryname.text = self.catarr[indexpath.row]         return cell     }      func loadcatlist(){         let networksession = urlsession.shared          var request = urlrequest(url: url(string: self.categoriesurl )!)          request.setvalue("application/json", forhttpheaderfield: "content-type")          let datatask = networksession.datatask(with: request) { (data, response, error) in             print("data downloaded")              let jsonreadable = nsstring(data: data!, encoding: string.encoding.utf8.rawvalue)              print(jsonreadable!)             do{                  let json = json(jsonreadable!)                  (_,json):(string, json) in json {                     let catname  = json["category_name"].stringvalue                     let catimage = json["image"].stringvalue                      self.catarr.append(catname)                     self.catimage.append(catimage)                 }             }             catch{                 print("we have json exception")             }         }         //         datatask.resume()         print("downloading data")     }      func getcount(){         print(self.catarr.count)     } } 

i have tried various methods add data dictionaries failed , giving me nil. not sure doing wrong on here.

ps: not want retrieve , testing purpose therefore receiving 2 values , adding them dict.

final result:

as answer suggested below 1 of problems , after way receiving data , appending them arrays how wrong replacing following code inside statement made work.

let json = json(data!)  print("the json data \(json)")  (_,json):(string, json) in json {      let catname = json["category_name"].stringvalue     print("the catimage \(catname)")     let catimage = json["image"].stringvalue     self.catarr.append(catname)     self.catimage.append(catimage) }  dispatchqueue.main.async {     self.mycollectionview.reloaddata() } 

you receiving nil because network call async, when table displayed nil @ moment , , when data comes not reload collectionview, need add following after for-in loop of json

dispatchqueue.main.async {   self.mycollectionview.reloaddata() } 

update:

you should return number of items number of elements in datasource, in case self.catarr, modify code follows:

func collectionview(_ collectionview: uicollectionview, numberofitemsinsection section: int) -> int {         return self.catarr.count }