Creating NSDate from components without “timezone

问题:

I have a function

func createDate(day: Int, month: Int, year: Int) -> NSDate {
    var comp = NSDateComponents()
    comp.day = day
    comp.month = month
    comp.year = year

    var cal = NSCalendar.currentCalendar()

    if var date = cal.dateFromComponents(comp) {
        return date
    }

    return NSDate()
}

If I call it with

createDate(07, 01, 1984)

the output is 1984-01-06 23:00:00 +0000. I assume that there is some influence from the time zone. How can I adjust my code so that the output will be 1984-01-07 00:00:00 +0000? What am I getting wrong here? How am I confused?

回答1:

There is no need to use NSDateComponents to input time. NSCalendar already has a method for you to input your date using your local time. It is called dateWithEra. "+0000" it is not your localTime (CET) it is UTC time. Your timeZone is not stored with your NSDate object, only the corresponding UTC date and time for your localTime input.

let myDate = NSCalendar.currentCalendar().dateWithEra(1, year: 1984, month: 1, day: 7, hour: 0, minute: 0, second: 0, nanosecond: 0)!


myDate.descriptionWithLocale(NSLocale.currentLocale())!   // "Saturday, January 7, 1984 at 12:00:00 AM Brasilia Standard Time"


NSTimeZone.localTimeZone().secondsFromGMT

回答2:

Don't worry about the log output. It will be an unformatted date. The actual date seems to be exactly what you intended.

If you want to show the exact date, you have to display it using a NSDateFormatter.