swift秒表的实现

class ViewController: UIViewController {

@IBOutlet weak var playBtn: UIButton!
@IBOutlet weak var pauseBtn: UIButton!
初始化秒表
var Counter = 0.0
var Timer = NSTimer()

定义一个bool值
var IsPlaying = false

override func preferredStatusBarStyle() -> UIStatusBarStyle {
return UIStatusBarStyle.LightContent
}

override func viewDidLoad() {
timeLabel.text = String(Counter)
super.viewDidLoad()
}

@IBOutlet weak var timeLabel: UILabel!
@IBAction func resetButtonDidTouch(sender: AnyObject) {
Timer.invalidate()
IsPlaying = false
Counter = 0
timeLabel.text = String(Counter)
playBtn.enabled = true
pauseBtn.enabled = true
}

@IBAction func playButtonDidTouch(sender: AnyObject) {
if(IsPlaying) {
return
}
playBtn.enabled = false
pauseBtn.enabled = true

<span style="white-space:pre">	</span>启动计时器方法
Timer = NSTimer.scheduledTimerWithTimeInterval(0.1, target: self, selector: #selector(ViewController.UpdateTimer), userInfo: nil, repeats: true)
IsPlaying = true
}

@IBAction func pauseButtonDidTouch(sender: AnyObject) {

playBtn.enabled = true
pauseBtn.enabled = false

<span style="white-space:pre">	</span>关闭计时器方法
Timer.invalidate()
IsPlaying = false

}

func UpdateTimer() {
Counter = Counter + 0.1
timeLabel.text = String(format: "%.1f", Counter)
}

}