How to get list of all UTC abbreviation in ios? - ios

Question

I have an app where i want to provide a list of UTC timezone so that the user could select destination time. I have all the country abbreviations in picker view. But i want UTC abbreviations.
Can anyone please suggest me how could i achieve this.
Thanks

Answer 1

You can use the knownTimeZoneNames property of NSTimeZone for all timezones.
[NSTimeZone knownTimeZoneNames]
Or you can use abbreviationDictionary for getting all abbreviations
[[NSTimeZone abbreviationDictionary] allKeys]
If you want time of these timezones, the use the below code
NSArray *abbs = [[NSTimeZone abbreviationDictionary] allKeys];
for (id eachObj in abbs) {
NSString *dateStr = [self dateFromTimeZoneAbbreviation:eachObj];
NSLog(#"%#",dateStr);
}
define the method as
-(NSString *)dateFromTimeZoneAbbreviation:(NSString *)abb {
NSString *dateStr;
NSTimeZone *currentTimeZone = [NSTimeZone localTimeZone];
NSTimeZone* timeZoneFromAbbreviation = [NSTimeZone timeZoneWithAbbreviation:abb];
NSInteger currentGMTOffset = [currentTimeZone secondsFromGMTForDate:[NSDate date]];
NSInteger gmtOffset = [timeZoneFromAbbreviation secondsFromGMTForDate:[NSDate date]];
NSTimeInterval gmtInterval = currentGMTOffset - gmtOffset;
NSDate *destinationDate = [[NSDate alloc] initWithTimeInterval:gmtInterval sinceDate:[NSDate date]] ;
NSDateFormatter *dateFormatters = [[NSDateFormatter alloc] init];
[dateFormatters setDateFormat:#"dd-MMM-yyyy hh:mm"];
/*[dateFormatters setDateStyle:NSDateFormatterShortStyle];
[dateFormatters setTimeStyle:NSDateFormatterShortStyle];
[dateFormatters setDoesRelativeDateFormatting:YES];*/
[dateFormatters setTimeZone:[NSTimeZone systemTimeZone]];
dateStr = [dateFormatters stringFromDate: destinationDate];
NSLog(#"DateString : %#, TimeZone : %#", dateStr , timeZoneFromAbbreviation.abbreviation);
return dateStr;
}

Answer 2

NSLog(#"%#", [NSTimeZone knownTimeZoneNames]);//viewDidLoad
for(id timezone in [NSTimeZone knownTimeZoneNames]){
NSLog(#"%#",[self getTimeZoneStringForAbbriviation:timezone]);
NSLog(#"%#", timezone);
}
-(NSString*)getTimeZoneStringForAbbriviation:(NSString*)abbr{
NSTimeZone *atimezone=[NSTimeZone timeZoneWithName:abbr];
int minutes = (atimezone.secondsFromGMT / 60) % 60;
int hours = atimezone.secondsFromGMT / 3600;
NSString *aStrOffset=[NSString stringWithFormat:#"%02d:%02d",hours, minutes];
return [NSString stringWithFormat:#"GMT%#",aStrOffset];
}