Question

我在swift工作，想要每分钟都运行一个函数。我想用倒计时器更新标签，剩下多少分钟，直到下一次更新。

我有一个基本版本

end

当我在应用程序上查看页面时更新，但我希望它每分钟自动更新。我看过NSTimer，我相信它可以用这个来完成（如图所示：How to make a countdown with NSTimer on Swift）但是我不知道如何在一分钟之后才开始它，只有在一定时间后显示

编辑：到目前为止，我有以下内容

    if let date = newDate {
        let formatter : NSDateFormatter = NSDateFormatter()
        formatter.dateFormat = "HH:mm"
        formatter.timeZone = NSTimeZone.defaultTimeZone()

        let string : NSString = formatter.stringFromDate(date)

        let calendar = NSCalendar.currentCalendar()
        let comp = calendar.components([.Minute], fromDate: date)
        let minute = comp.minute

        let remaining : Int = 60 - minute
        var mins = "s"
        if remaining == 1 {
            mins = ""
        }

        self.refreshInLabel.text = "Refreshes at \(string) - \n \(remaining) minute\(mins) remaining "
    }

我想知道是否有更好的方式

Answer 1

我建议您在每分钟开始使用时启动NSNotification。当您收到NSNotification来电时，会收到如下函数：

var yourTimer = NSTimer()
func callWhenNotificationReceived(){
  yourFuncToFire()
  yourTimer = NSTimer.scheduledTimerWithTimeInterval(60, target: self, selector: #selector(YourViewController.yourFuncToFire) , userInfo: nil, repeats: true)
}

Answer 2

var TotalTime:Int = 0
var timer: NSTimer?


triggerCountDownTimerFor(time:Int)

func triggerCountDownTimerFor(time:Int)
{
   totalTime = time
    timer = NSTimer.scheduledTimerWithTimeInterval(1, target:self, selector: #selector(LoginViewController.updateTimer), userInfo: nil, repeats: true)
}

func updateTimer()
{
    let date = NSDate()
    let formatter : NSDateFormatter = NSDateFormatter()
    formatter.dateFormat = "HH:mm"
    formatter.timeZone = NSTimeZone.defaultTimeZone()

    let string : NSString = formatter.stringFromDate(date)

    let calendar = NSCalendar.currentCalendar()
    let comp = calendar.components([.Minute], fromDate: date)
    let minute = comp.minute

    let remaining : Int = TotalTime - minute
    var mins = "s"
    if remaining == 1 {
        mins = ""
    }

    print("Refreshes at \(string) - \n \(remaining) minute\(mins) remaining ")




}

Swift：每分钟运行一次func

2 个答案: