Code Optimisation Swift iOS - (Completion Handler , singleton) - ios

Question

This is my netWorkOperations classs
import UIKit
class NetworkOpertions: NSObject {
private var actors = [Actor]()
func getMethod(OnCompletion:#escaping (Any)-> Void) {
guard let url = URL(string: "http://microblogging.wingnity.com/JSONParsingTutorial/jsonActors")else {return}
let session = URLSession.shared.dataTask(with:url){
(data,response,error) in
if let data = data {
print("This is Data:", data)
do{
let decoder = JSONDecoder()
let downloadedActors = try decoder.decode(Actors.self, from: data)
let res = data
}
OnCompletion(res)
}
catch let err{
print(err.localizedDescription)
// OnCompletion()
}
}
}
session.resume()
}
}
This is my ViewController class
import UIKit
class ViewController: UIViewController, UITableViewDataSource,UITableViewDelegate,UIPopoverPresentationControllerDel egate{
private var actors = [Actor]()
#IBOutlet var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
self.title = "Welcome"
tableView.delegate = self
tableView.dataSource = self
downloadJson()
tableView.tableFooterView = UIView()
}
func downloadJson() {
let netWork = NetworkOpertions()
let reponseValue = netWork.getMethod(){ (fetchValue)-> Void in
Here its throwing error:Invalid conversion from throwing function of type '(_) throws -> Void' to non-throwing function type '(Any) -> Void'
if fetchValue != nil {
print("MY VAlue:",fetchValue)
let decoder = JSONDecoder()
let downloadedActors = try decoder.decode(Actors.self, from: data)
self.actors = downloadedActors.actors
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
}
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return actors.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let cell = tableView.dequeueReusableCell(withIdentifier: "ActorCell") as? ActorCell else { return UITableViewCell() }
cell.nameLbl.text = actors[indexPath.row].name
cell.DOBLbl.text = actors[indexPath.row].dob
cell.countryCell.text = actors[indexPath.row].country
if let imageURL = URL(string: actors[indexPath.row].image) {
DispatchQueue.global().async {
let data = try? Data(contentsOf: imageURL)
if let data = data {
let image = UIImage(data: data)
DispatchQueue.main.async {
cell.imgView.image = image
}
}
}
}
return cell
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 70
}
}
please help me how to solve this error:
Invalid conversion from throwing function of type '(_) throws -> Void'
to non-throwing function type '(Any) -> Void'

Answer 1

The reason of the error is the missing do catch block wrapping the decode line
do {
let downloadedActors = try decoder.decode(Actors.self, from: data)
self.actors = downloadedActors.actors
DispatchQueue.main.async {
self.tableView.reloadData()
}
} catch { print(error) }