How to change/raise an old variable when opening the app? - ios

Question

I am new to Swift and already tried to search on this topic, but I don't know how it's called, so I'm asking it now. I want to make a sort of Cookie Clicker. Every time I press the button there will be more money.
I already managed to save "the money" when I open the app, but now I want to add to that "old" money when I click the button. Does anyone know how to do this?
Here is my code:
import UIKit
import AVFoundation
var employers = 0
var money = 0
class ViewController: UIViewController {
#IBOutlet var score: UILabel!
#IBOutlet var moneysecond: UILabel!
#IBOutlet var employees: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
#IBAction func clickbutton(_ sender: Any) {
money = money + 20
score.text = "$\(money).-"
UserDefaults.standard.set(score.text, forKey: "dollar")
score.text = "$\(money).-"
}
override func viewDidAppear(_ animated: Bool) {
if let x = UserDefaults.standard.object(forKey: "dollar") as? String {
score.text = x
}
}
}

Answer 1

Do not store some String into the UserDefaults but the actual value of money, e.g. an Int. And set the value of money initially.
Right now you set the displayed text to the value you have stored, then on click you increment a money variable which does not have anything to do with the value read from the UserDefaults, therefore you lose the information of what was previously set during the last application run.
Proposal:
move money into the ViewController
change viewDidLoad to read a value of UserDefaults.standard.integer(forKey: "dollar") into money
in viewDidAppear use the value of money to set the text
in clickbutton remove the first or second score.text assignment and do not store score.text but money in the UserDefaults

Answer 2

Actually this is the same idea as luk2302's suggestion but in code
class ViewController: UIViewController {
#IBOutlet var score: UILabel!
#IBOutlet var moneysecond: UILabel!
#IBOutlet var employees: UILabel!
var money = 0
var employers = 0
override func viewDidLoad() {
super.viewDidLoad()
money = UserDefaults.standard.integer(forKey: "dollar")
}
#IBAction func clickbutton(_ sender: Any) {
money = += 20
score.text = "$\(money).-"
UserDefaults.standard.set(money, forKey: "dollar")
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
score.text = "$\(money).-"
}
}