timer for IOS #tags: timer, swift, mytimer

MyTimer.swift

//  MyTimer.swift
//
//  Created by Paul on 10/11/18.
//  Copyright © 2018 Paul Lehn. All rights reserved.
//

import Foundation

class MyTimer: NSObject {
    
    var startTime: TimeInterval! = TimeInterval()
    var time: Double! = 40
    var timer = Timer()
    var timerEndedCallback: (() -> Void)!
    var timerInProgressCallback: ((_ elapsedTime: Double) -> Void)!
    
    func startTimer(timerEnded: @escaping () -> Void, timerInProgress: ((_ elapsedTime: Double) -> Void)!) {
        if !timer.isValid {
            let aSelector : Selector = #selector(MyTimer.updateTime)
            timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: aSelector, userInfo: nil, repeats: true)
            startTime = NSDate.timeIntervalSinceReferenceDate
            timerEndedCallback = timerEnded
            timerInProgressCallback = timerInProgress
        }
    }
    
    @objc func updateTime() {
        var currentTime = NSDate.timeIntervalSinceReferenceDate
        var elapsedTime = currentTime - startTime
        var seconds = time - elapsedTime
        
        if seconds > 0 {
            elapsedTime -= TimeInterval(seconds)
            timerInProgressCallback(elapsedTime)
        } else {
            timer.invalidate()
            timerEndedCallback()
        }
    }
}