Timer animation not starting - swift

Question

I'm trying to animate a circular progress timer animation for a timer app, but the timer counts and the animation never starts.
import UIKit
class TimerPage: UIViewController {
let timeLeftShapeLayer = CAShapeLayer()
let bgShapeLayer = CAShapeLayer()
var timeLeft: TimeInterval = 60
var endTime: Date?
var timeLabel = UILabel()
var timer = Timer()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor(white: 0.94, alpha: 1.0)
drawBgShape()
drawTimeLeftShape()
addTimeLabel()
// here you define the fromValue, toValue and duration of your animation
strokeIt.fromValue = 0
strokeIt.toValue = 1
strokeIt.duration = 60
// add the animation to your timeLeftShapeLayer
timeLeftShapeLayer.add(strokeIt, forKey: nil)
// define the future end time by adding the timeLeft to now Date()
endTime = Date().addingTimeInterval(timeLeft)
timer = Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(updateTime), userInfo: nil, repeats: true)
}
// here you create your basic animation object to animate the strokeEnd
let strokeIt = CABasicAnimation(keyPath: "strokeEnd")
func drawBgShape() {
bgShapeLayer.path = UIBezierPath(arcCenter: CGPoint(x: view.frame.midX , y: view.frame.midY), radius:
150, startAngle: (3*CGFloat.pi) / 2, endAngle: -CGFloat.pi / 2, clockwise: false).cgPath
bgShapeLayer.strokeColor = UIColor.blue.cgColor
bgShapeLayer.fillColor = UIColor.clear.cgColor
bgShapeLayer.lineWidth = 15
view.layer.addSublayer(bgShapeLayer)
}
func drawTimeLeftShape() {
timeLeftShapeLayer.path = UIBezierPath(arcCenter: CGPoint(x: view.frame.midX , y: view.frame.midY), radius:
100, startAngle: (3*CGFloat.pi) / 2, endAngle: -CGFloat.pi / 2, clockwise: false).cgPath
timeLeftShapeLayer.strokeColor = UIColor.white.cgColor
timeLeftShapeLayer.fillColor = UIColor.clear.cgColor
timeLeftShapeLayer.lineWidth = 15
view.layer.addSublayer(timeLeftShapeLayer)
}
func addTimeLabel() {
timeLabel = UILabel(frame: CGRect(x: view.frame.midX-50 ,y: view.frame.midY-25, width: 100, height: 50))
timeLabel.textAlignment = .center
timeLabel.text = timeLeft.time
view.addSubview(timeLabel)
}
#objc func updateTime() {
if timeLeft > 0 {
timeLeft = endTime?.timeIntervalSinceNow ?? 0
timeLabel.text = timeLeft.time
} else {
timeLabel.text = "00:00"
timer.invalidate()
}
}
}
extension TimeInterval {
var time: String {
return String(format:"%02d:%02d", Int(self/60), Int(ceil(truncatingRemainder(dividingBy: 60))) )
}
}
I tested this out on a separate test project by itself, and it works perfectly fine. But when I add it to my actual app as part of a segue, the animation never starts.