ios - Converting UTC date format to local nsdate

Question

I am getting from my server a string date in UTC time zone and I need to convert it to the local time zone.

MY CODE:

let utcTime = "2015-04-01T11:42:00.269Z"    
let dateFormatter = NSDateFormatter()
dateFormatter.timeZone = NSTimeZone(name: "UTC")
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"
let date = dateFormatter.dateFromString(utcTime)
println("utc: (utcTime), date: (date)")

this prints -

utc: 2015-04-01T11:42:00.269Z, date: Optional(2015-04-01 11:42:00 +0000)

if I remove

dateFormatter.timeZone = NSTimeZone(name: "UTC") 

it prints

utc: 2015-04-01T11:42:00.269Z, date: Optional(2015-04-01 08:42:00 +0000)

my local time zone is UTC +3 and in the first option I get UTC in the second option I get UTC -3

I should get

utc: 2015-04-01T11:42:00.269Z, date: Optional(2015-04-01 14:42:00 +0000)

So how do I convert the UTC date format to local time?

Answer 1

Something along the following worked for me in Objective-C :

// create dateFormatter with UTC time format
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss"]; 
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];
NSDate *date = [dateFormatter dateFromString:@"2015-04-01T11:42:00"]; // create date from string

// change to a readable time format and change to local time zone
[dateFormatter setDateFormat:@"EEE, MMM d, yyyy - h:mm a"];
[dateFormatter setTimeZone:[NSTimeZone localTimeZone]];
NSString *timestamp = [dateFormatter stringFromDate:date];

I keep these two websites handy for converting different time formats: http://www.w3.org/TR/NOTE-datetime

http://benscheirman.com/2010/06/dealing-with-dates-time-zones-in-objective-c/

In Swift it will be:

// create dateFormatter with UTC time format
  let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
        dateFormatter.timeZone = NSTimeZone(name: "UTC") as TimeZone?
        let date = dateFormatter.date(from: "2015-04-01T11:42:00")// create   date from string

        // change to a readable time format and change to local time zone
        dateFormatter.dateFormat = "EEE, MMM d, yyyy - h:mm a"
        dateFormatter.timeZone = NSTimeZone.local
        let timeStamp = dateFormatter.string(from: date!)