main thread as it may lead to UI unresponsiveness. Please switch to an asynchronous networking API such as URLSession....

위 오류 나면 

URLSession을 이용해서 이미지 불러오기.

 

let defaultSession = URLSession(configuration: .default)

        

        guard let url = URL(string:str) else {

            //TODO

            return

        }

        

        //Request

        let request = URLRequest(url: url)



        //dataTask

        var dataTask: URLSessionDataTask?

        dataTask = defaultSession.dataTask(with: request) { data, response, error in



            // getting Data Error

             guard error == nil else {

                 print("Error occur: \(String(describing: error))")

                

                 return

             }

            

            if let myData = data  {

                print("myData")

              //TODO

            }

                

            DispatchQueue.main.sync {

                self.addContentScrollView()

            }

            

        }

        dataTask?.resume()