iOS UITableView Not Showing - ios

Question

I'm kinda new to iOS, was working on network fetching from the GitHub API but not able to show the users in the table view. Below is the code,
View Controller:
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var avatarImage: UIImageView!
#IBOutlet weak var userName: UILabel!
#IBOutlet weak var usersTableView: UITableView!
var network = Network()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
network.delegate = self
usersTableView.dataSource = self
}
override func viewWillAppear(_ animated: Bool) {
network.network()
}
}
extension ViewController: NetworkDelegate {
func updateTableView() {
DispatchQueue.main.async {
self.usersTableView.reloadData()
}
}
}
extension ViewController: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if let users = network.users {
print(users.count)
return users.count
} else {
return 0
}
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
print("CALLED")
let cell = tableView.dequeueReusableCell(withIdentifier: "userCell", for: indexPath) as! UserViewCell
return cell
}
}
btw, the identifier is from the .xib file, the identifier matches, I don't think the problem is occurring here.
Network File
import Foundation
protocol NetworkDelegate {
func updateTableView()
}
class Network {
var users: [GitHub]?
var delegate: NetworkDelegate?
func network() {
let url = "https://api.github.com/users"
let request: URLRequest?
if let URL = URL(string: url) {
request = URLRequest(url: URL)
URLSession.shared.dataTask(with: request!) { result, response, error in
if let data = result {
// print(String(data: data, encoding: .utf8)!)
self.users = self.parseJSON(data)
self.delegate?.updateTableView()
} else {
print(error!.localizedDescription)
}
}
.resume()
}
}
private func parseJSON(_ data: Data) -> [GitHub]? {
let json = JSONDecoder()
do {
let decodedData = try json.decode([GitHub].self, from: data)
// print(decodedData)
return decodedData
} catch {
print(error.localizedDescription)
}
return nil
}
}
The GitHub API Model
struct GitHub: Codable {
let login: String
let id: Int
let node_id: String
let avatar_url: String
let gravatar_id: String
let url: String
let html_url: String
let followers_url: String
let following_url: String
let gists_url: String
let starred_url: String
let subscriptions_url: String
let organizations_url: String
let repos_url: String
let events_url: String
let received_events_url: String
let type: String
let site_admin: Bool
}
When I run this code on the simulator, the output is blank (Below the label)
Not able to figure out where I'm doing wrong
Thanks In Advance.

Answer 1

Try to refactor you code using a completion handler without using the delegation pattern.
in your network file:
enum ApiError: Error {
case network(Error)
case genericError
case httpResponseError
case invalidData
case decoding
// you can handle your specific case
}
func network(completion: #escaping ( _ error: ApiError?, _ users: [GitHub]?)-> Void) {
let url = "https://api.github.com/users"
let request: URLRequest?
if let URL = URL(string: url) {
request = URLRequest(url: URL)
URLSession.shared.dataTask(with: request!) { result, response, error in
if let error = error {
completion(.network(error), nil)
return
}
guard let httpResponse = response as? HTTPURLResponse,
(200...299).contains(httpResponse.statusCode) else {
completion( .httpResponseError, nil)
return
}
guard let data = result else {
completion(.invalidData, nil)
return
}
do {
let decodedData = try JSONDecoder().decode([GitHub].self, from: data)
completion(nil, decodedData)
} catch {
completion(.decoding, nil)
}
}
.resume()
}
}
then inside your ViewController you can use it this way:
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
network.network { [weak self] error, users in
guard let self = self else { return }
if let error = error {
print(error)
return
}
DispatchQueue.main.async {
guard let users = users else { return }
self.users = users
self.tableView.reloadData()
}
}
}
if it still doesn't show and cellForRow doesn't get called, you probably have a problem with your constraints and the tableView frame is zero (either height, width or both).
Try to debug setting a breakpoint inside numberOfRowsInSection and then in your debug area po tableView or just print the tableView and check if width or height is zero. it will be probably get called a few times. The first time the frame should be zero but at some point you should get a frame with height and width. If don't then check your constraints.
You can check my example which has a table view 375 x 641

Answer 2

If your cell is a xib file then you have to register your cell with tableView.
before calling datasource in viewDidLoad
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
usersTableView(UINib(nibName: "userCell", bundle: nil), forCellReuseIdentifier: "userCell")
network.delegate = self
usersTableView.dataSource = self
}