iOS NSDate（）返回不正确的时间

Question

I am trying to get current date in Swift using NSDate() . When I create breakpoint and stop application, I can see that there is 3 hours difference with devices' system time. Application is running on real iPhone. How to fix this?

I also wrote the following in App Delegate to be sure:

NSTimeZone.setDefaultTimeZone(NSTimeZone(name: "Europe/Kiev")!)

But it still does not work.

Answer 1

It doesn't return the wrong time. It returns exactly the right time. NSDate doesn't have any timezone information. Right now, my computer and your computer will report the exact same time when we call NSDate ().

NSLog displays NSDate in UTC. That's just what it displays. So if we both call NSLog right now, your computer will log the same date and time as mine. Because it is the same date and time.

If you want to process an NSDate (for example, to display the date and time to a user) you use an NSCalendar. The NSCalendar translates between NSDate, which is the same everywhere in the world, to the values that you want to display in your user interface, which will be different in London or in Kiev. If I look on my watch right now, I will see a different time than you see on your watch, and that is what NSCalendar is there for.

Answer 2

Here is the conversion for swift 3.0 :

func getCurrentLocalDate()-> Date {
    var now = Date()
    var nowComponents = DateComponents()
    let calendar = Calendar.current
    nowComponents.year = Calendar.current.component(.year, from: now)
    nowComponents.month = Calendar.current.component(.month, from: now)
    nowComponents.day = Calendar.current.component(.day, from: now)
    nowComponents.hour = Calendar.current.component(.hour, from: now)
    nowComponents.minute = Calendar.current.component(.minute, from: now)
    nowComponents.second = Calendar.current.component(.second, from: now)
    nowComponents.timeZone = TimeZone(abbreviation: "GMT")!
    now = calendar.date(from: nowComponents)!
    return now as Date
}

Answer 3

还值得检查您的测试设备的日期/时间是否设置为较早的日期。

Answer 4

For Swift 2.2 this function did the trick for me:

func getCurrentLocalDate()-> NSDate {
    var now = NSDate()
    let nowComponents = NSDateComponents()
    let calendar = NSCalendar.currentCalendar()
    nowComponents.year = NSCalendar.currentCalendar().component(NSCalendarUnit.Year, fromDate: now)
    nowComponents.month = NSCalendar.currentCalendar().component(NSCalendarUnit.Month, fromDate: now)
    nowComponents.day = NSCalendar.currentCalendar().component(NSCalendarUnit.Day, fromDate: now)
    nowComponents.hour = NSCalendar.currentCalendar().component(NSCalendarUnit.Hour, fromDate: now)
    nowComponents.minute = NSCalendar.currentCalendar().component(NSCalendarUnit.Minute, fromDate: now)
    nowComponents.second = NSCalendar.currentCalendar().component(NSCalendarUnit.Second, fromDate: now)
    nowComponents.timeZone = NSTimeZone(abbreviation: "GMT")
    now = calendar.dateFromComponents(nowComponents)!
    return now
}

If you want a different timezone you can change it directly, or even better, pass it as a function parameter.

Answer 5

You can also use Locale to get current time and date.

        let today = NSDate()
        let locale = NSLocale.current
        print("Time of today: \(today.description(with: locale))")

Answer 6

This func returns Now in a current time zone.

func convertDate(date:Date) -> Date {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
    var comp = DateComponents()
    let calendar = Calendar.current
    comp.year = Calendar.current.component(.year, from: date)
    comp.month = Calendar.current.component(.month, from: date)
    comp.day = Calendar.current.component(.day, from: date)
    comp.hour = Calendar.current.component(.hour, from: date)
    comp.minute = Calendar.current.component(.minute, from: date)
    comp.second = Calendar.current.component(.second, from: date)
    comp.timeZone = TimeZone(abbreviation: "GMT")
    var dateFromCalendar = Date()
    if let calendarDate = calendar.date(from: comp) {
        dateFromCalendar = calendarDate
    }
    return dateFromCalendar
}

To use:

    let now = Date()
    let convertedDate = convertDate(date: now)