Appending Data from Alamofire Not working

Question

I get the Data from alamofire however it's not appending. I think the reason for this is because it's happening Async. Just couldn't figure out the best way to fix this in my code. Thanks in Advance for the help.

 var allItems = [Item]();

@discardableResult func createItem() -> Item {
        let newItem = Item(name: "Grocery", description: "Milk Egg Cheese", priority: "High")
//        let newItem1 = Item(name: "Test", description: "Tes", priority: "Test")
        
        AF.request("https://mobile-app-i.herokuapp.com/list/list").responseJSON { response in
            switch response.result {
            case .success(let value):
                            DispatchQueue.main.async {
                                if let value = value as? [NSDictionary] {
                                for d in value {
                                        print(d["description"])
                                    let dataItem = Item(name: d["name"]! as! String, description: d["description"]! as! String, priority: d["priority"]! as! String)
                                    self.allItems.append(dataItem)
                                }
                            }
                            }
            case .failure(let error):
                print(error)
            }
        }
//        allItems.append(newItem1)
          allItems.append(newItem)
          
          return newItem
    }

A simple fix could be to use the completion block to wait for the data delivery. — El Tomato, Dec 10 '20 at 01:53
The problem is that newItem is returned before it can be set. See http://www.programmingios.net/you-cant-use-a-value-after-it-has-been-set-by-asyncronous-code/ — matt, Dec 10 '20 at 02:02
You don't need to return item, you have access to all items through the array. You don't need the Dispatch block either. — cora, Dec 10 '20 at 04:37

score 0 · Answer 1 · answered Dec 11 '20 at 06:10

Fixed it by adding completion block

        AF.request("https://mobile-app-i.herokuapp.com/list/list").responseJSON { response in
            switch response.result {
            case .success(let value):
                            DispatchQueue.main.async {
                                print(type(of: value))
                                if let value = value as? [NSDictionary] {
                                    completionHandler(value)
                            }
                            }
            case .failure(let error):
                print(error)
            }
        }
    }

Call like so

fetchData(completionHandler: {(returnedData)-> Void in
             //Do whatever you want with your returnedData JSON data.
             //when you finish working on data you can update UI
            for (i, d) in returnedData.enumerated() {
                    print(d["description"])
                
                    self.itemStore.createNewItem(name: d["name"]! as! String, description: d["description"]! as! String, priority: d["priority"]! as! String)
              
               
            }

Appending Data from Alamofire Not working

1 Answers1