iOS快速倒数计时器不会停止

Question

我正在尝试制作一个倒计时计时器，该计时器从60秒开始倒计时，然后在计数到0时停止计时。 任何建议表示赞赏。 码：

@IBOutlet var timeCounter: UILabel!
var second = 60

var timer = NSTimer()

var timerRunning = true

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.


    setTimer()
    timerCounting()
 }

func setTimer(){
    second  -= 1
    timeCounter.text = "\(second)"


}

func timerCounting(){
    if(timerRunning == true){

        timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("setTimer"), userInfo: nil, repeats: true)
        timerRunning = true
        if second == 0 {
            timerRunning = false
            timer.invalidate()


        }


    }


}

Answer 1

您必须将无效性移到setTimer函数中，因为永远不会触发它的当前位置，因为timerCounting仅在开始时被调用一次。

func setTimer(){
    second  -= 1
    timeCounter.text = "\(second)"
    if second == 0 {
        timerRunning = false
        timer.invalidate()
    }
}

Answer 2

在操场上玩这个

import XCPlayground
XCPlaygroundPage.currentPage.needsIndefiniteExecution = true
import Foundation


@objc class C:NSObject {
    var timer: NSTimer?
    var second = 5
    func setTimer(){
        if c.second < 0 {
            print("the timer fires the last time here ...")
            timer?.invalidate()
        } else {
            print(second)
            second  -= 1
        }
    }
}

let c = C()

func timerCounting(){
        c.timer = NSTimer.scheduledTimerWithTimeInterval(1, target: c, selector: Selector("setTimer"), userInfo: nil, repeats: true)
}

timerCounting()