我有一个标签,其值为“ 03:48”。
我想像音乐播放器一样倒计时。我怎样才能做到这一点?
03:48 03:47 03:46 03:45 … 00:00
var musictime =3:48 func stringFromTimeInterval(interval: NSTimeInterval) -> String { let interval = Int(interval) let seconds = interval % 60 let minutes = (interval / 60) return String(format: "%02d:%02d", minutes, seconds) } func startTimer() { var duration=musictime.componentsSeparatedByString(":") //split 3 and 48 var count = duration[0].toInt()! * 60 + duration[1].toInt()! //224 second timerCounter = NSTimeInterval( count ) NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "onTimer:", userInfo: nil, repeats: true) } @objc func onTimer(timer:NSTimer!) { // Here is the string containing the timer // Update your label here //println(stringFromTimeInterval(timerCounter)) statusLabel.text=stringFromTimeInterval(timerCounter) timerCounter!-- }
您应该看看NSDate属性timeIntervalSinceNow。您所需要做的就是使用NSDate方法dateByAddingTimeInterval将将来的日期设置为endDate ,如下所示:
class ViewController: UIViewController { @IBOutlet weak var timerLabel: UILabel! var remainingTime: NSTimeInterval = 0 var endDate: NSDate! var timer = NSTimer() override func viewDidLoad() { super.viewDidLoad() remainingTime = 228.0 // choose as many seconds as you want (total time) endDate = NSDate().dateByAddingTimeInterval(remainingTime) // set your future end date by adding the time for your timer timer = NSTimer.scheduledTimerWithTimeInterval(0.1, target: self, selector: "updateLabel", userInfo: nil, repeats: true) // create a timer to update your label } func updateLabel() { timerLabel.text = endDate.timeIntervalSinceNow.mmss } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() // Dispose of any resources that can be recreated. } } // you will need this extension to convert your time interval to a time string extension NSTimeInterval { var mmss: String { return self < 0 ? "00:00" : String(format:"%02d:%02d", Int((self/60.0)%60), Int(self % 60)) } var hmmss: String { return String(format:"%d:%02d:%02d", Int(self/3600.0), Int(self / 60.0 % 60), Int(self % 60)) } }