在倒数计时器（swift3）之前添加倒数计时器

Question

In my code if you press the startButton countdown goes from 60 - 0 . All I want to do is have a countdown from 3 - 0 then countdown from 60 - 0. Think of it mark, set, go then start the countdown timer from 60 seconds to 0.

 import UIKit
class ViewController: UIViewController {

@IBOutlet weak var startButton: UIButton!
@IBOutlet weak var timerLabel: UILabel!

var seconds = 60
var timer = Timer()
var isTimerRunning = false
var resumeTapped = false

@IBAction func startButtonTapped(_ sender: UIButton) {
    if isTimerRunning == false {
        runTimer()
        self.startButton.isEnabled = false
    }
}

func runTimer() {
    timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: (#selector(ViewController.updateTimer)), userInfo: nil, repeats: true)
    isTimerRunning = true

}
@IBAction func resetButtonTapped(_ sender: UIButton) {
    timer.invalidate()
    seconds = 60
    timerLabel.text = timeString(time: TimeInterval(seconds))
    isTimerRunning = false

}

//MARK: - Public Method
func updateTimer(){
    if seconds < 1 {
        timer.invalidate()
        //Send alert to indicate time's up.
    } else {
        seconds -= 1
        timerLabel.text = timeString(time: TimeInterval(seconds))
    }
}

func timeString(time:TimeInterval) -> String {
    let hours = Int(time) / 3600
    let minutes = Int(time) / 60 % 60
    let seconds = Int(time) % 60
    return String(format:"%02i:%02i:%02i", hours, minutes, seconds)
    }}

Answer 1

Hmmm, before we start trying to chain timers maybe we could just use one and display it as though it were two, one after the other...

Now your first timer starts at 3, and the second at 60, 3 is less than 60...

Maybe we could start the timer at 64 but display the time as remainder(time, 61), those remainders would go 3, 2, 1, 0, 60, 59, ...

Remainder in Swift is % .

So something like:

• start the time at 64
• change the parameter name of timeString to actualTime , and
• add let time = actualTime % 61 as its first line.

BTW: The constant 60 occurs twice in your code, think about using a let constant for it and use that to reset variables. Introduce a similar constant for the pre-countdown, etc.

HTH