How to display the list of data initially in View Controller - swift

Question

This is my Pokedex. It works per say... A minor issue I have with this is when you initially open the app, it doesn't show the list of data, just blank. When you enter something in search bar, it appears even when you delete everything and no letters in the search bar.
I looked for how to display the list initially and compared with a functional code but can't figure out what caused this.
Any helps and ideas will be appreciated.
Here is my main ViewController:
import UIKit
class ViewController: UITableViewController, UISearchBarDelegate {
#IBOutlet weak var searchBar: UISearchBar!
var pokemon: [Pokemon] = []
var filteredData: [Pokemon] = []
func capitalize (text: String) -> String {
function and followed by the remaining text without the first letter
return text.prefix(1).uppercased() + text.dropFirst()
}
override func viewDidLoad() {
super.viewDidLoad()
let url = URL(string: "https://pokeapi.co/api/v2/pokemon?limit=151")
guard let u = url else {
return
}
URLSession.shared.dataTask(with: u) { (data, reponse, error) in
guard let data = data else {
return
}
do {
let pokemonList = try JSONDecoder().decode(PokemonList.self, from: data)
self.pokemon = pokemonList.results
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
catch let error {
print("\(error)")
}
}.resume()
searchBar.delegate = self
filteredData = pokemon
}
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return filteredData.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "PokemonCell", for: indexPath)
cell.textLabel?.text = capitalize(text: filteredData[indexPath.row].name)
return cell
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "PokemonSegue" {
if let destination = segue.destination as? PokemonViewController {
destination.pokemon = filteredData[tableView.indexPathForSelectedRow!.row]
}
}
}
func searchBar (_ searchBar: UISearchBar, textDidChange searchText: String) {
filteredData = []
if searchText == "" {
filteredData = pokemon
}
else {
for pokemon in pokemon {
if pokemon.name.lowercased().contains(searchText.lowercased()){
filteredData.append(pokemon)
}
}
}
self.tableView.reloadData()
}
}

Answer 1

this:
let pokemonList = try JSONDecoder().decode(PokemonList.self, from: data)
self.pokemon = pokemonList.results
DispatchQueue.main.async {
self.tableView.reloadData()
}
Happens asynchroniously after you receive the data and way after this
searchBar.delegate = self
filteredData = pokemon
is executed, you can put breakpoints and check for yourself.
You should assign pokemon to filteredData in the "do" statement
right before tableView.reloadData()

Answer 2

URLSession works asynchronously. Move the line
filteredData = pokemon
into the completion handler of the data task
do {
let pokemonList = try JSONDecoder().decode(PokemonList.self, from: data)
self.pokemon = pokemonList.results
self.filteredData = pokemonList.results
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
catch let error {
print("\(error)")
}
}.resume()
searchBar.delegate = self
}
And your function capitalize is redundant, String has a property capitalized
And this is a more efficient version of textDidChange
func searchBar (_ searchBar: UISearchBar, textDidChange searchText: String) {
if searchText.isEmpty {
filteredData = pokemon
} else {
filteredData = pokemon.filter { $0.name.range(of: searchText, options: .caseInsensitive) != nil }
}
self.tableView.reloadData()
}