Error - Thread 1: signal SIGABRT (unrecognized selector sent to instance)

Question

I'm making an app where you need to indicate the amount of time that a label appears for and that amount of time is counted down at the bottom of the page.

When I run my app on the Xcode simulator, the chronometre label displays "Optional (*indicated number)" when I want it to only display the indicated number. Once it's displayed for a second, I get taken to my App Delegate and it says Thread 1: signal SIGABRT.

The following error is also shown: 2015-02-22 21:05:50.860 MemoPres.New[71008:12980314] -[MemoPres_New.ViewController subtractTime:]: unrecognized selector sent to instance 0x7fbab24299c0 2015-02-22 21:05:50.862 MemoPres.New[71008:12980314] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[MemoPres_New.ViewController subtractTime:]: unrecognized selector sent to instance 0x7fbab24299c0'.

Help would be greatly appreciated.

The following is all of my code:

class ViewController: UIViewController {


@IBOutlet weak var chronometre: UILabel!
@IBOutlet weak var prochainpointLabel: UILabel!
@IBOutlet weak var pointactuelLabel: UILabel!
@IBOutlet weak var point1Textfield: UITextField!
@IBOutlet weak var point1tempsTextfield: UITextField!
@IBOutlet weak var point2Textfield: UITextField!
@IBOutlet weak var point2tempsTextfield: UITextField!


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 presenterButton(sender: AnyObject) {

    var timer = NSTimer()
    var seconds = point1tempsTextfield.text.toInt()

    pointactuelLabel.text = point1Textfield.text
    prochainpointLabel.text = point2Textfield.text
    chronometre.text = "\(seconds)"



        timer = NSTimer.scheduledTimerWithTimeInterval(1.0, target: self, selector: ("subtractTime:"), userInfo: nil, repeats: true)



    func subtractTime(dt:NSTimer){
        seconds!--
        chronometre.text = "\(seconds)"

    }


        }
}

Answer 1

You need to declare your method subtractTime() outside your IBAction. The same applies to your timer and second vars.

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var progressView: UIProgressView!
    @IBOutlet weak var strTimer: UILabel!
    @IBOutlet weak var btnStartCancel: UIButton!
    @IBOutlet weak var btnPauseResume: UIButton!

---

    var timer = Timer()
    var startTime: TimeInterval = 0
    var timeLeft: TimeInterval = 45
    var isTimerON = false
    var isPaused = false

---

    func updateTimer() {
        if isTimerON && !isPaused {
            strTimer.text = (startTime - Date().timeIntervalSinceReferenceDate).time
            progressView.progress = (1 - Float(startTime - Date().timeIntervalSinceReferenceDate) / 45)
        }
    }

---

    override func viewDidLoad() {
        super.viewDidLoad()
        timer = .scheduledTimerWithTimeInterval(1/20, target: self, selector: "updateTimer", userInfo: nil, repeats: true)
        RunLoop.main.addTimer(timer, forMode: .common)
    }

---

    @IBAction func pauseResumeAction(_ sender: Any) {
        isPaused = !isPaused
        if isPaused {
            timeLeft = startTime - Date().timeIntervalSinceReferenceDate
        }
        startTime = Date().dateByAddingTimeInterval(timeLeft).timeIntervalSinceReferenceDate
        btnPauseResume.setTitle( !isPaused ? "Pause" : "Resume", forState: .normal)
    }

---

    @IBAction func startCancelAction(_ sender: Any) {
        isTimerON = !isTimerON
        isPaused = false
        timeLeft = 45

        startTime = isTimerON ? Date().dateByAddingTimeInterval(timeLeft).timeIntervalSinceReferenceDate : timeLeft
        btnStartCancel.setTitle(!isTimerON ? "Start" : "Cancel",  forState: .normal)
        progressView.progress = 0
        btnPauseResume.setTitle("Pause",  forState: .normal)
        strTimer.text = "00:45"
        btnPauseResume.enabled = isTimerON
    }
}

---

extension TimeInterval {
    var time: String {
        String(format: "%02d:%02d", Int((self/60)%60), Int(self%60))
    }
}