Keep updating NSTimer label after segue - ios

Question

I have a number of initial settings in the viewDidLoad:
countDownLabel.alpha = 1
countDownLabel.text = "01:30"
swipeLeft.alpha = 0
swipeRight.alpha = 0
pressPlayToStartOr.alpha = 0
swipeToChangeTheSeq.alpha = 0
countDownPauseLbl.alpha = 0
I have an NSTimer (I've put func update () of the timer inside inside viewDidLoad as well, while it is triggered by a UIButton outside viewDidLoad). The timer continues running when I segue from the UI View Controller. When I segue back to the Timer View Controller, I can hear the sound of the timer running, but the Timer View Controller is refreshed to it's initial state and you can run the timer again so that they overlap. The programmatic segue after the timer finishes doesn't work in this case. I understand that I may have used the wrong approach, but hope it can be fixed. How can I make the label update, regardless of where I'am at in the app.

Answer 1

The effect:
In SingletonTimer.swift:
//
// SingletonTimer.swift
// testSwiftUITextField
//
// Created by leo on 2016/12/17.
// Copyright © 2016年 leo. All rights reserved.
//
import UIKit
class SingletonTimer: NSObject {
private static let sharedInstance = SingletonTimer()
class var sharedSingletonTimer:SingletonTimer {
return sharedInstance
}
var timeCount:Int = 100
func countDown() {
timeCount -= 1
timer_closure(timeCount)
}
lazy var timer:Timer = {
var timer:Timer
if #available(iOS 10.0, *) {
timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true, block: { (timer) in
self.countDown()
})
} else {
// Fallback on earlier versions
timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(countDown), userInfo: nil, repeats: true)
}
return timer
}()
var timer_closure:(Int)->Void = { (count) in
}
}
In ViewController.swift:
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var label: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
}
In ViewController2.swift:
import UIKit
class ViewController2: UIViewController {
#IBOutlet weak var label: UILabel!
var timer:Timer? = nil
override func viewDidLoad() {
super.viewDidLoad()
timer = SingletonTimer.sharedSingletonTimer.timer
SingletonTimer.sharedSingletonTimer.timer_closure = { (timeCount) in
print("\(timeCount)")
self.label.text = "\(timeCount)s !"
}
if timer != nil {
timer?.fire()
}
}
}