How to stop MBProgressHUD and add a subview when the server is not returning data

Question

In my app I have this class to get data from my server:

class Api{

func loadOffers(completion:(([Offers])-> Void), offer_id: String, offerStatus:String){
    
    
    let myUrl = NSURL(string: "http://www.myServer.php/api/v1.0/offers.php")
    let request = NSMutableURLRequest(URL: myUrl!)
    request.HTTPMethod = "POST"
    let postString = "offer_id=\(offer_id)&offerStatus=\(dealStatus)&action=show"
    request.HTTPBody = postString.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true)
    
    let task = NSURLSession.sharedSession().dataTaskWithRequest(request)
        { data, response, error in              
            if error != nil {                  
                println("error\(error)")                 
            }else{   
               var err:NSError?
                
               let jsonObject : AnyObject! = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil)
               
                if let dict = jsonObject as? [String: AnyObject] {
                    
                if let myOffers = dict["offers"] as? [AnyObject] {
               
                var offers = [Offers]()
                                       
                for offer in myOffers{
                                    
                let offer = Offers(dictionary: offer as! NSDictionary)
                                    
                offers.append(offer)                       
                                    
                let priority = DISPATCH_QUEUE_PRIORITY_DEFAULT
                                    dispatch_async(dispatch_get_global_queue(priority, 0 )){
                                                                                   dispatch_async(dispatch_get_main_queue()){
                                            
                completion(offers)
                                            
                             }         
                           }                                
                        }
                    }
                }                
            }            
      }
    task.resume()       
   }
 }

then in my View Controller I load the model:

    class MyViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {


    var offers: [Offers]!

    func loadModel() {
    let loadingNotification = MBProgressHUD.showHUDAddedTo(self.view, animated: true)
    loadingNotification.mode = MBProgressHUDMode.Indeterminate
    loadingNotification.labelText = "updating your offers..."
    offers = [Offers]()
    let api = Api()
    api.loadOffers(didLoadOffers , offer_id: dealIdent!, offerStatus: "open")
  
    }

    func didLoadOffers(offers:[Offers]){
    
    self.offers = offers
    self.tableView.reloadData()
    MBProgressHUD.hideAllHUDsForView(self.view, animated: true)
    self.refreshControl.endRefreshing()
    }

    override func viewWillAppear(animated: Bool) {
    
    loadModel()
    
    }
 }

Everything works except that when the JSON dictionary is empty, meaning that there no offers the MBProgressHUD keep spinning.

I would like stop the activity indicator adding a subview instead which says that there are no offers. Any Suggestion would be greatly appreciated.

I tried:

if offers.isEmpty{ MBProgressHUD.hideAllHUDsForView(self.view, animated: true) }

and also

if offers == 0 { MBProgressHUD.hideAllHUDsForView(self.view, animated: true) }

but it's not working

Answer 1

This is happening because you set the HUD in main queue but are trying to remove from another one. All UI related changes should be done in main_queue()

Try using this code

dispatch_async(dispatch_get_main_queue(), { 

  // your code to modify HUD here

});