Unrecognised Selector... bug? - ios

Question

I edited some code based on what others have pointed out, but I keep getting the error stated above, saying I sent an "unrecognised selector". The selector for my timer, originally the error, has been amended, but Xcode is still complaining.
Here is my code:
import UIKit
class ViewController: UIViewController {
#IBOutlet var instructionsNew: UILabel!
#IBOutlet var lockStatusNew: UIImageView!
#IBOutlet var timerText: UILabel!
#IBAction func hackLockButton(sender: AnyObject){
var counter = 0
let timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "updateCounter", userInfo: nil, repeats: true)
func updateCounter() {
timerText.text = String(counter++)
}
while(timerText.text == "1") {instructionsNew.text = "loading"}
while(timerText.text == "2"){instructionsNew.text = "loading."}
while(timerText.text == "3") {instructionsNew.text = "loading.."}
while(timerText.text == "4"){instructionsNew.text = "loading..."}
while(timerText.text == "5") {instructionsNew.text = "hack successful!"
lockStatusNew.image = UIImage(named: "unlocked.png")
timer.invalidate()
}
}
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.
}
}
Please help me spot the problem. Thanks!

Answer 1

The issue is, you added the updateCounter inside the hackLockButton function.
You should place the method outside that function and it will work.
#IBAction func hackLockButton(sender: AnyObject)
{
// Code here
}
func updateCounter()
{
timerText.text = String(counter++)
}
Suggestion:
You don't want to write while(timerText.text == "1") {instructionsNew.text = "loading"} for showing that label. It can cause an infinite loop and hang your UI. Instead use a switch case like:
switch(counter)
{
case 1: instructionsNew.text = "loading"
// Write other cases too
}

Answer 2

I think you really, really need to get your head around how a timer works.
Your application has a run loop. When the user does anything, the run loop will call the appropriate code in your program, runs the code, and finish when that code is run. For example when you tap on a button, the run loop will call your button callback function, wait for it to finish, and then it can wait for the next thing to happen.
A scheduled timer inserts calls into that run loop. So every second the run loop calls updateCounter. updateCounter should do some stuff, and then return. It's not supposed to wait in a while loop at all. The while () inside it is badly, badly wrong.
You also do some other things upside down. You use your timerText label to control things. That's wrong. The label should display things. The updateCounter can update the counter, but then all other actions should depend on the value of the counter, not on the value of a user interface label! Imagine your boss tells you to display not 1, 2, 3, 4, 5 but one, two, three, four, five. You obviously change what goes into the label. But with your code you have to change code everywhere that reads the text of the label. Now imagine you don't want one, two, three, but the right text in the user's language...