iphone - Convert GMT NSDate to device's current Time Zone

Question

I'm using Parse.com to store some values:

These are GMT values. How do I convert these to the device's current time zone and get NSDate as a result?

Answer 1

NSDate is always represented in GMT. It's just how you represent it that may change.

If you want to print the date to label.text, then convert it to a string using NSDateFormatter and [NSTimeZone localTimeZone], as follows:

NSString *gmtDateString = @"08/12/2013 21:01";

NSDateFormatter *df = [NSDateFormatter new];
[df setDateFormat:@"dd/MM/yyyy HH:mm"];

//Create the date assuming the given string is in GMT
df.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:0];
NSDate *date = [df dateFromString:gmtDateString];

//Create a date string in the local timezone
df.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:[NSTimeZone localTimeZone].secondsFromGMT];
NSString *localDateString = [df stringFromDate:date];
NSLog(@"date = %@", localDateString);

// My local timezone is: Europe/London (GMT+01:00) offset 3600 (Daylight)
// prints out: date = 08/12/2013 22:01