Parse JSON date into NSDate depending user settings

Question

I have a problem for converting a brut JSON string date:

"created_at" = "2012-12-22T21:39:22Z";

into an NSDate.

Here is my current category for that:

- (NSDate*)dateWithJSONString
{
[NSDateFormatter setDefaultFormatterBehavior:NSDateFormatterBehavior10_4];
 NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss'Z'"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
[dateFormatter setCalendar:[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]];
NSDate *date = [[NSDate alloc] init];
date = [dateFormatter dateFromString:self];
return date;        
}

The problem is this works for 95% of my cases, but if some users use AM/PM instead of 24H in there date and time settings combined with custom international settings, the date is not created from the json string.

I read this discussion but I can't find the good way to work with all my international users and settings.

I added this for example:

[dateFormatter setLocale:[NSLocale currentLocale]];

but it changed nothing. The NSDate is not created if I set my iPhone with AM/PM instead of 24H.

AM/PM NSDate schema: 2013-01-21 07:12:43 AM +0000

24H NSDate schema: 2013-01-21 07:12:43 +0000

What did I miss ? Is there something to update in the date format ?

I added this: [jsonDateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"]]; and this is OK now. — alex.bour, Jan 21 '13 at 11:26
This technote is for that: http://developer.apple.com/library/ios/#qa/qa1480/_index.html — alex.bour, Jan 21 '13 at 11:26

score 12 · Answer 1 · answered Jun 18 '13 at 12:44

You just need to set the correct dateFormat, rest of your code is correct.

[dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ssz"];

The character Z in your dateString is a valid date format defined by ISO8601, it denotes that the date string is in UTC timezone. So you don't need to set the timezone to the formatter. Formatter can recognise the timezone from character Z. So if it is ignored there would be mismatches in timezone unless a timezone is specified to dateFormatter.

If your dateString is not uniform, put a fall back check for dateFormat. Check for converted date to be nil, if nil use the fall back dateFormat.

Also no need to set the calendar to dateFormatter unless there is change in the calendar type of date string and system calendar.

score 9 · Answer 2 · answered Feb 23 '14 at 23:58

9

I was trying to do the same thing, but in my case the JSON date also included milliseconds, the date being sourced from MongoDB.

Here is the formatting snippet when you have milliseconds (e.g. 2014-02-27T09:30:00.000Z)

[dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.SSSz"];

answered Feb 23 '14 at 23:58

Ted Avery

5,639
3
30
29

This is the javascript json date format. Refer to: https://stackoverflow.com/a/15952652/4081597 – Rob C Apr 12 '18 at 18:42

score 1 · Answer 3 · edited May 23 '17 at 11:47

Please use below code which is working perfect for me.

 NSString* strDate = [jsonObj objectForKey:@"created_at"];
 NSDate *date = [self dateWithJSONString:strDate];

- (NSDate*)dateWithJSONString:(NSString*)dateStr
{
    // Convert string to date object
    NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
    [dateFormat setDateFormat:@"yyyy'-'MM'-'dd'T'HH':'mm':'ss'Z'"];
    NSDate *date = [dateFormat dateFromString:dateStr];

    // This is for check the output
    // Convert date object to desired output format
    [dateFormat setDateFormat:@"yyyy'-'MM'-'dd'T'HH':'mm':'ss'Z'"]; // Here you can change your require output date format EX. @"EEE, MMM d YYYY"
    dateStr = [dateFormat stringFromDate:date];
    NSLog(@"Date -- %@",dateStr);

    return date;
}

Date Format Problem

Parse JSON date into NSDate depending user settings

3 Answers3

Linked