I am a beginner in Swift. I've exhausted all my trial and errors and need help!!
I am creating a scoreboard project using a UITableView with a Custom Cell that holds a UILabel and a UIButton. After a button press the UILabel increments by one to simulate a point for the player. I am having trouble saving the point in UILabel so that every time I open the app the point for that player remains. I've tried using UserDefaults, structs, and delegates but have't had any luck...I could be doing it wrong. I just need to know what the proper approach is for this.
Note: I am able to save the player name successfully from the UIAlertController so that when I open the app the names are still there unless I delete them, but haven't had any luck saving the points for each name itself, they still remain "0".
It should look like this when I close then open the app, but it only does this when the app is opened:
Scoreboard UITableView - Screenshot
Here's the ViewController code:
import UIKit
class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
var items = [String]()
@IBOutlet weak var listTableView: UITableView!
@IBAction func addItem(_ sender: AnyObject) {
alert()
}
override func viewDidLoad() {
super.viewDidLoad()
listTableView.dataSource = self
self.items = UserDefaults.standard.stringArray(forKey:"items") ?? [String]()
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell") as! PointsCell
cell.textLabel?.text = items[indexPath.row]
return cell
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return items.count
}
func saveData() {
UserDefaults.standard.set(items, forKey: "items")
}
func alert(){
let alert = UIAlertController(title: "Add Player", message: "", preferredStyle: .alert)
alert.addTextField{
(textfield) in
textfield.placeholder = " Enter Player Name "
}
let add = UIAlertAction(title: "Add", style: .default)
{
(action) in guard let textfield = alert.textFields?.first else {return}
if let newText = textfield.text
{
self.items.append(newText)
self.saveData()
let indexPath = IndexPath(row: self.items.count - 1, section: 0)
self.listTableView.insertRows(at: [indexPath], with: .automatic)
}
}
let cancel = UIAlertAction(title: "Cancel", style: .cancel) {
(alert) in
}
alert.addAction(add)
alert.addAction(cancel)
present(alert, animated: true, completion: nil)
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
items.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .automatic)
saveData()
}
}
Here is my custom cell code called PointsCell:
import UIKit
class PointsCell: UITableViewCell {
var winScore = 0
@IBOutlet weak var scoreUILabel: UILabel!
@IBAction func pointButtonPressed(_ sender: Any) {
winScore += 1
scoreUILabel.text = "\(winScore)"
}
}
The points still remains 0 because you are note saving them, firstly you need points for each player so you need to combine player name and score into object.
class Player:NSObject, Codable{
let name: String
var score : Int
init(name: String, score: Int) {
self.name = name
self.score = score
}
override var description: String{
return "Name :" + self.name + " Score :" + String(self.score )
}
}
Swift 4 introduced the Codable protocol, by adopting Codable on your own types enables you to serialize them to and from any of the built-in data formats.
Now you can easily access a player with name and score.
var players = [Player]()
To get stored value from UserDefaults
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if let items: Data = UserDefaults.standard.object(forKey: "items") as? Data{
self.players = try! PropertyListDecoder().decode([Player].self, from: items)
self.listTableView.reloadData()
}
}
When you adding new player to your list create new instance of Player and add it to list.
func alert(){
let alert = UIAlertController(title: "Add Player", message: "", preferredStyle: .alert)
alert.addTextField{
(textfield) in
textfield.placeholder = " Enter Player Name "
}
let add = UIAlertAction(title: "Add", style: .default)
{
(action) in guard let textfield = alert.textFields?.first else {return}
if let newText = textfield.text
{
let player = Player(name: newText, score: 0)
self.players.append(player)
let indexPath = IndexPath(row: self.players.count - 1, section: 0)
self.listTableView.insertRows(at: [indexPath], with: .automatic)
}
}
let cancel = UIAlertAction(title: "Cancel", style: .cancel) {
(alert) in
}
alert.addAction(add)
alert.addAction(cancel)
present(alert, animated: true, completion: nil)
}
Now update your UITableViewDataSource method as new list item.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell") as! PointsCell
cell.player = players[indexPath.row]
return cell
}
now need to update saveData method to save new list into UserDefaults, you'll call this method whenever you want to save your list.
func saveData() {
UserDefaults.standard.set(try! PropertyListEncoder().encode(self.players), forKey: "items")
}
PointsCell class also need to be updated as new object type:
class PointsCell: UITableViewCell {
@IBOutlet weak var scoreUILabel: UILabel!
@IBOutlet weak var nameUILabel: UILabel!
var player: Player? {
didSet{
if let name = player?.name {
self.nameUILabel?.text = name
}
if let score = player?.score {
self.scoreUILabel?.text = String(score)
}
}
}
@IBAction func pointbuttonPressed(_ sender: Any) {
if self.player != nil{
let score = self.player?.score ?? 0
self.player?.score = score + 1
scoreUILabel.text = String(self.player?.score ?? 0)
}
}
}