timer doesn't work in cocoa/mac OS in Swift 4 - swift

Question

I cant see why this time doesnt update. Been looking the entire day. I don't know if is something related to being my first MacOs project, and there's maybe something that's escaping me, but I'd love some help.
import Cocoa
class TextViewController: NSViewController {
#IBOutlet weak var text: NSScrollView!
#IBOutlet weak var dreadline: NSTextField!
var seconds: Int = 60
var timer: Timer?
var theWork = Dreadline(email: "", worktime: 0)
override func viewDidLoad() {
super.viewDidLoad()
print(seconds)
let timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { timer in
print(self.seconds)
self.updateTimer()
} // this is the timer that doesn't work no matter what I try :(
}
#objc func updateTimer() {
if seconds < 1 {
timer?.invalidate()
} else {
seconds -= 1 //This will decrement(count down)the seconds.
dreadline.stringValue = "Dreadline: " + timeString(time: TimeInterval(seconds)) //This will update the label.
}
}

Answer 1

A very common mistake: You are creating a local timer which is not the same as the declared property.
Replace
let timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { timer in
print(self.seconds)
self.updateTimer()
} // this is the timer that doesn't work no matter what I try :(
with
self.timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { timer in
print(self.seconds)
self.updateTimer()
} // this is the timer that doesn't work no matter what I try :(
The self before timer is actually not mandatory.
And set the timer to nil after invalidation to avoid a retain cycle
if seconds < 1 {
timer?.invalidate()
timer = nil
}
On the other hand you can use the local timer by deleting the property and change the code to
Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { timer in
print(self.seconds)
self.updateTimer(timer)
}
func updateTimer(_ timer : Timer) {
if seconds < 1 {
timer.invalidate()
} else {
seconds -= 1 //This will decrement(count down)the seconds.
dreadline.stringValue = "Dreadline: " + timeString(time: TimeInterval(seconds)) //This will update the label.
}
}