使用Xcode创建标签中的计时器时，在Swift 5中出现错误

Question

我正在用Xcode中的Swift5编写一个应用程序。在一个视图控制器上，我创建了一个计时器，从20分钟到0分钟。我有一个我认为是成功的代码，但它抛回了一个错误。在队伍中

timer=timer.ScheduleDTimer(TimeInterval:0.01，target:self，selector:#selector(SkippingViewController.UpdateTimer)，userInfo:nil，repeats:true)

import UIKit

class SkippingViewController: UIViewController {

    @IBOutlet weak var timeLabel: UILabel!

    @IBOutlet weak var startWorkoutButton: UIButton!

    @IBOutlet weak var pauseWorkoutButton: UIButton!

    var timer = Timer()
    var counter = 20.00
    var isRunning = false

    override func viewDidLoad() {
        super.viewDidLoad()


        timeLabel.text = "\(counter)"
        startWorkoutButton.isEnabled = true
        pauseWorkoutButton.isEnabled = false
        // Do any additional setup after loading the view.
    }

    @IBAction func startWorkoutButtonDidTouch(_ sender: Any) {

        if !isRunning {
            timer = Timer.scheduledTimer(timeInterval: 0.01, target: self, selector: #selector(SkippingViewController.updateTimer), userInfo: nil, repeats: true)

            startWorkoutButton.isEnabled = false
            pauseWorkoutButton.isEnabled = true
            isRunning = true
        }

    }

    @IBAction func pauseWorkoutButtonDidTouch(_ sender: Any) {

        func updateTimer() {
            counter -= 0.01
            timeLabel.text = String(format: "%.01f", counter)
        }


    }
}

Answer 1

您的问题是，SkippingViewController.Swift中没有名为“Update Timer”的方法。您错误地将该方法放在方法'Pause WorkoutButtonDidTouch'中。为了解决该错误，在SkippingViewController.Swift中插入以下代码：

@objc func updateTimer() { 
    counter -= 0.01
    timeLabel.text = String(format: "%.01f", counter)
}