how to get same date in string and nsdate? - ios

Question

I have Issue in dateformatter. I add my code as below:
NSDate *currentDate = [NSDate date];
NSLog(#"Current Date: %#",currentDate); //Current Date: 2016-10-14 08:07:15 +0000
NSTimeZone *timeZone = [NSTimeZone localTimeZone];
NSString *tzName = [timeZone name];
NSLog(#"Current TimeZone: %#",tzName); //Current TimeZone: Asia/Kolkata
NSTimeZone *systemTimeZone = [NSTimeZone systemTimeZone];
NSString *SyTZName = [systemTimeZone name];
NSLog(#"System TimeZone: %#",SyTZName); //System TimeZone: Asia/Kolkata
NSString *strCurrentDate = [NSString stringWithFormat:#"%#",[NSDate date]];
NSLog(#"Current Date: %#",strCurrentDate);//Current Date: 2016-10-14 08:07:47 +0000
NSDateFormatter* localDateFrm = [[NSDateFormatter alloc] init] ;
[localDateFrm setTimeZone:[NSTimeZone timeZoneWithName:#"IST"]];
[localDateFrm setDateFormat:#"dd-MM-yyyy hh:mm a"];
NSString* local_string = [localDateFrm stringFromDate:currentDate];
NSLog(#"local_string: %#",local_string);//local_string: 14-10-2016 01:37 PM
NSDateFormatter* local_dateFormatter = [[NSDateFormatter alloc] init] ;
[local_dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:#"IST"]];
[local_dateFormatter setDateFormat:#"dd-MM-yyyy hh:mm a"];
NSDate *date = [local_dateFormatter dateFromString:local_string];
NSLog(#"date : %#",date);//date : 2016-10-14 08:07:00 +0000
at last I need 01:37 PM but I get 08:07:00 +0000.when I convert string into NSDate its not give me expected reply(01:37 PM). so the time is different.
so please help me for this.
Thanks.

Answer 1

NSDate will always return utc or gmt date, if you want it to in your local timezone then you need to convert it to string with stringFromDate method of NSDateFormatter.
So, when you want to display your date with your local timezone just convert it to string and then show. And when you want it to as NSDate you can easily convert string to date with dateFromString method and it will return date in utc or gmt again.
And usually you need to display your date in label or any UI so you must need string, you can't show nsdate on label. So, this is standard approach to deal with NSDate
Update :
You can use this date as localnotification's firedate also. execute below demo,
NSString *str = #"2016-10-14 08:07:00";
NSDateFormatter *df = [[NSDateFormatter alloc]init];
[df setDateFormat:#"yyyy-MM-dd hh:mm:ss"];
NSDate *date = [df dateFromString:str];
NSLog(#"date : %#",[df dateFromString:str]);
UILocalNotification *notification = [[UILocalNotification alloc]init];
notification.fireDate = date;
notification.alertTitle = #"title";
NSLog(#"notification : %#",notification);
and check log for notification, it will show firetime as per your local timezone!!
Second thing you can set timezone also for notification like notification.timeZone = ...;