转换纳秒到毫秒不工作

Question

我想从NSCalendarUnit获得毫秒。我能够达到纳秒，但是数字太多了。我只想要2个数字。这是我的代码：

var startDate = NSDate() 
let dateComponents = NSCalendar.currentCalendar().components(NSCalendarUnit.CalendarUnitNanosecond, fromDate: startDate, toDate: NSDate(), options: nil) 

let millisecond = Double(dateComponents.nanosecond)/1000000 
let strFraction = String(format: "%02d", round(millisecond) 
timeLabel.text = "\(strFraction)" 

timeLabel显示00，这不是它应该显示的。我怎样才能获得从NSCalendar显示毫秒？

Answer 1

以下工作对我来说（一些XCode7改变...）：

var startDate = NSDate() 
let dateComponents = NSCalendar.currentCalendar().components(NSCalendarUnit.Nanosecond, fromDate: startDate, toDate: NSDate(), options: NSCalendarOptions(rawValue: 0)) 

let millisecond = Int(Double(dateComponents.nanosecond)/1000000 + 0.5) 
let strFraction = String(format: "%02d", millisecond)