swift - 如何停止循环 swift 3

Question

我正在尝试制造一种滴答声，这种声音一直持续到您按下减号按钮为止。我遇到的唯一问题是我无法单击减号按钮，因为加号按钮一直处于按下状态。它可能一直处于按下状态，因为它无法退出循环。已经感谢您的回答!

import UIKit
import AVFoundation
import AudioToolbox
import Foundation

class ViewController: UIViewController {
    @IBOutlet weak var telLabel: UILabel!

    var number = 0
    var timeline = "no"

    @IBAction func plus(_ sender: Any) {
        number += 1
        telLabel.text = "\(number)"
        timeline = "yes"
        tijdlijn()
    }

    func tijdlijn(){
        while timeline == "yes"{
            AudioServicesPlaySystemSound(SystemSoundID(1103))
            sleep(2)
        }
    }

    /*   if timeline = "yes"{
    repeat{
        AudioServicesPlaySystemSound(SystemSoundID(1103))
        sleep(3)
    } while timeline == "yes"
     */

    //4095
    @IBAction func min(_ sender: Any) {
        number -= 1
        telLabel.text = "\(number)"
        timeline = "no"
    }
}

Answer 1

我建议你使用 Timer 来完成这样的任务。尝试使用这个:

@IBOutlet weak var telLabel: UILabel!

var number = 0

var timeline = false

var timer: Timer!

@IBAction func plus(_ sender: Any) {

    timeline = !timeline

    if timeline {
        number += 1
        timer = Timer.scheduledTimer(timeInterval: 2, target: self, selector: #selector(self.tijdlijn), userInfo: nil, repeats: true)

    } else {
        number -= 1

        timer.invalidate()
    }

    telLabel.text = "\(number)"
}

func tijdlijn(){
    AudioServicesPlaySystemSound(SystemSoundID(1103))
}

并且只使用一个 Action touchupinside - func plus。删除减号 touchupinside 操作。