java - swift : Date difference

Question

我找不到快速编写此代码的方法，但如何获取现在和年底之间的日期差异？我已经在 java 中完成了这项工作，但找不到在 swift 中执行相同操作的方法。这是我写的 java 逻辑:

        Calendar today = Calendar.getInstance();
        Calendar endOfYear = Calendar.getInstance();
        endOfYear.setTime(new Date(0));
        endOfYear.set(Calendar.DAY_OF_MONTH, 31);
        endOfYear.set(Calendar.MONTH, 11);
        endOfYear.set(Calendar.YEAR, Calendar.getInstance().get(Calendar.YEAR));

        double t = endOfYear.getTimeInMillis() - today.getTimeInMillis();
        String time = new SimpleDateFormat("0:ss", Locale.US).format(t);

这当然只输出倒计时的秒数，而我正试图在 swift 中这样做。

更新:

我只有:

func timer() {
    let time = NSDateFormatter.localizedStringFromDate(NSDate(), dateStyle: NSDateFormatterStyle.NoStyle, timeStyle: NSDateFormatterStyle.MediumStyle)
    timeLabel.text = "\(time)"
}

这就是我不想要的整个时间......

Answer 1

花了我一些时间，但这正是我要找的:

    let date = NSDate()
    let calendar = NSCalendar.currentCalendar()
    let components = calendar.components([.Day, .Month, .Year, .Hour, .Minute, .Second, .Nanosecond], fromDate: date)
    let now = NSCalendar.currentCalendar().dateWithEra(1, year: components.year, month: components.month, day: components.day, hour: components.hour, minute: components.minute, second: components.second, nanosecond: components.nanosecond)!
    let newYears = NSCalendar.currentCalendar().dateWithEra(1, year: components.year, month: 12, day: 31, hour: 01, minute: 00, second: 00, nanosecond: 00)!


    let units: NSCalendarUnit = [.Day, .Month, .Year, .Hour, .Minute, .Second]
    let difference = NSCalendar.currentCalendar().components(units, fromDate: now, toDate: newYears, options: [])

    let seconds = difference.second

这显示为一种计时器格式，类似于 this它说这是 n 天，n 小时，n 分钟，n 秒。 不过谢谢!