Swift - passing text and int from vc1 to vc 2 (uitextfield -> label in vc2) - swift

Question

Passing only input text from textfield to label in second VC works!! But i want when user type number 10 in uitextfield, ( 1 ticket is 2 euros so 10 tickets * 2 euro is 20) and when i click PAY button, so that SUM can be displayed in label in second VC, i think that viewdidload in VC2 is happening before prepareForSegue, i don't know. It works when i click second time on PAY button, but not when i first click PAY button where label displays zero, help :) Embedded in navigation controller for navigation.
VC1
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var howManyTickets: UITextField!
var sumTicketsAndPriceOfTickets = Int()
var priceOfTicket = 2 // euros
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func platiTeKarte(sender: AnyObject) {
sumTicketsAndPriceOfTickets = howManyTickets.text.toInt()! * priceOfTicket
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let driver = segue.destinationViewController as! primaocViewController
var whatToPass = sumTicketsAndPriceOfTickets
driver.receiver = whatToPass
}
}
VC2
import UIKit
class primaocViewController: UIViewController {
#IBOutlet weak var displaySum: UILabel!
var receiver:Int!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.displaySum.text = String(receiver)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}

Answer 1

If your button is wired directly to a segue, then you don't need an #IBAction as well. As you are seeing, the prepareForSegue is happening before the #IBAction for your Pay button. Just compute your value in prepareForSegue:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let driver = segue.destinationViewController as! primaocViewController
driver.receiver = (howManyTickets.text.toInt() ?? 0) * priceOfTicket
}
I changed the calculation of the pay to use the nil coalescing operator ??. This is generally a safer approach because if the toInt() returns nil for any reason, it will in this case just use 0 instead of crashing.