从没有“时区校正"的组件创建 NSDate [英] Creating NSDate from components without "timezone correction"

问题描述

我有一个功能

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()
}

如果我用

createDate(07, 01, 1984)

输出为 1984-01-06 23:00:00 +0000.我认为时区有一些影响.如何调整我的代码，使输出为 1984-01-07 00:00:00 +0000?我在这里出了什么问题?我怎么糊涂了?

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?

推荐答案

不需要使用 NSDateComponents 来输入时间.NSCalendar 已经有一种方法可以让您使用本地时间输入日期.它被称为 dateWithEra.+0000"它不是您的本地时间 (CET)，它是 UTC 时间.您的 timeZone 不与您的 NSDate 对象一起存储，仅存储您 localTime 输入的相应 UTC 日期和时间.

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

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