How do I update a label in a different view controller? - swift

Question

I’m very new to coding. I created a game and there is a scoreLabel in the top corner of GameViewController. I created another label in a different view controller (ShopViewController) called moneyLabel. I want the money label to be equal to the score. I made it so that my score label resets every time you start a new game, but I want my money to stay the same so that I can use the money for purchases in game.
I don’t know how to make it update. I tried: gameViewController = GameViewController() and then using code to update my label but it’s not working. My label isn’t updating at all. It stays at 0.

Answer 1

I think you have to use some model struct where you can add your score or any other data and easily manipulate it:
struct GameData{
var totalScore: Int = 0
var currentGameScore: Int = 0
func invalidateCurrentScore(){
totalScore += currentGameScore
currentGameScore = 0
//call this method when you need to set your current score to 0, and pass all the accumulated points to your total score (f.ex. in the end of the game)
}
//some other data like player's name and etc...
}
You also need to create a delegation protocol for using its method in ShopViewController and returning the game data to GameViewController:
protocol ShopViewControllerDelegate{
func updateGameData(by gameData: GameData)
}
GameViewController with new parts:
class GameViewConroller: UIViewController, ShopViewControllerDelegate{
#IBOutlet weak var scoreLabel: UILabel!
var gameData: GameData!
override func viewDidLoad(){
super.viewDidLoad()
gameData = GameData()
updateScoreLabel()
}
private func updateScoreLabel(){ //call it anyTime when you manipulate the score of current game
scoreLabel.text = "Score: \(gameData.currentGameScore)"
}
func updateGameData(by gameData: GameData){ //This is the delegate's method that ShopViewController needs to trigger when you buy something in the shop
self.gameData = gameData
updateScoreLabel()
}
override func prepare(for segue: UIStoryboardSegue,
sender: Any?){
if let shopViewController = segue.destination as? ShopViewController{
//passing game data to ShopViewController
shopViewController.gameData = self.gameData
shopViewController.delegate = self //!IMPORTANT
}
}
}
And these are some properties and methods that your ShopViewController should have:
class ShopViewController{
#IBOutlet weak var totalScoreLabel: UILabel!
var gameData: GameData!
var delegate: ShopViewControllerDelegate?
override func viewDidLoad(){
super.viewDidLoad()
updateTotalScoreLabel()
}
private func updateTotalScoreLabel(){
totalScoreLabel.text = "Total Score: \(gameData.totalScore + gameData.currentGameScore)"
}
private func purchasingSomething(){
//logic of getting price of an item
gameData.currentGameScore -= price
if gameData.currentGameScore < 0{
gameData.totalScore += gameData.currentGameScore
gameData.currentGameScore = 0
//if your current score is less than 0 after some purchase, your total score decreases and the current score becomes 0
}
updateTotalScoreLabel()
delegate?.updateGameData(by gameData: gameData) //Pass refreshed gameData back to the GameViewController
}
}
Also Swift has static variables, but it's very easy to use. Delegates bring more fun and makes code more pretty.
struct GameData{
static var totalScore: Int = 0
static var currentGameScore: Int = 0
}
Good luck and have fun with the game dev :)