Convert date time to NSDate from NSString - objective-c

Time zone always made trouble for me. This time I have to convert date-time , that I have in NSSTring to NSDate.
I am doing something like this.
NSString *myStringDate=#"14-11-2012 4:09:00 PM +0500"
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setTimeZone:[NSTimeZone systemTimeZone]];
[formatter setDateFormat:#"dd-MM-yyyy h:mm:ss a Z"];
NSDate *aDate = [formatter dateFromString:myStringDate];
NSLog(#"%#",aDate);
but I am having the output like this
14-11-2012 11:09:00 +0000
Also, no AM/PM is setting :-(
What I want is 14-11-2012 4:09:00 PM +0500 i.e same Date-Time that I have in string.
Thanks in anticipation.

the output of your converting is giving the GMT time
NSString *myStringDate=#"14-11-2012 4:09:00 PM +0500"
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setTimeZone:[NSTimeZone systemTimeZone]];
[formatter setDateFormat:#"dd-MM-yyyy h:mm:ss a Z"];
NSDate *aDate = [formatter dateFromString:myStringDate];
NSDateFormatter* df_utc = [[[NSDateFormatter alloc] init] autorelease];
[df_utc setTimeZone:[NSTimeZone timeZoneWithName:#"UTC"]];
[df_utc setDateFormat:#"yyyy.MM.dd G 'at' HH:mm:ss zzz"];
NSDateFormatter* df_local = [[[NSDateFormatter alloc] init] autorelease];
[df_local setTimeZone:[NSTimeZone timeZoneWithName:#"EST"]];
[df_local setDateFormat:#"yyyy.MM.dd G 'at' HH:mm:ss zzz"];
NSString* ts_utc_string = [df_utc stringFromDate:aDate];
NSString* ts_local_string = [df_local stringFromDate:aDate];

Here Is the Change need to be taken.
[formatter setDateFormat:#"dd-MM-yyyy h:mm:ss a "];
Thanks

The conversion looks correct, but the default output is in UTC time (+0000) and with a 24h clock which is why you don't get the AM/PM distinction (“01:00 PM” would be 13:00). You also need to format the output if you want a specific representation ([formatter stringFromDate:aDate])…
For the UTC issue you need to select the time zone of your choice, by giving that choice in place of [NSTimeZone systemTimeZone]. Try [NSTimeZone localTimeZone] for starters.

Related

Objective C - Convert DateTime to Local DateTime

I am pretty new to Objective C and it has been horrible experience to get the current device datetime in systemTimeZone. This is what I have:
NSDate *now = [NSDate date];
NSDateFormatter *DateFormatter=[[NSDateFormatter alloc] init];
[DateFormatter setTimeZone:[NSTimeZone systemTimeZone]];
[DateFormatter setDateFormat:#"MM-dd-yyyy HH:mm"];
NSString *currentDateTime = [DateFormatter stringFromDate:now];
NSDate *curDate = [DateFormatter dateFromString:currentDateTime];
Line 5 NSString has the correct local datetime in currentDateTime string variable. But Line 6 again switches back to UTC DateTime. I do not understand why it would switch back to UTC even though the DateFormatter has the systemTimezone set. Can you please help me find out what is that I am missing?
Just set the timeZone in the dateFormatter, This code is enough
NSString *dateString = #"24 08 2011 09:45PM";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"dd MM yyyy hh:mma"];
NSTimeZone* sourceTimeZone = [NSTimeZone timeZoneWithAbbreviation:#"BST"];
[dateFormatter setTimeZone:sourceTimeZone];
NSDate *dateFromString = [dateFormatter dateFromString:dateString];
The dateFromString will now have the date 24 08 2011 08:45PM(GMT).. Then to convert this to string with local time just code the following,
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[formatter setTimeZone:[NSTimeZone localTimeZone]];
[formatter setLocale:[NSLocale systemLocale]];
[dateFormatter setDateFormat:#"dd MM yyyy hh:mma"];
NSString *stringFromDAte = [dateFormatter stringFromDate:dateString];
or You can also try this one:
NSTimeInterval seconds; // assume this exists
NSDate* ts_utc = [NSDate dateWithTimeIntervalSince1970:seconds];
NSDateFormatter* df_utc = [[[NSDateFormatter alloc] init] autorelease];
[df_utc setTimeZone:[NSTimeZone timeZoneWithName:#"UTC"]];
[df_utc setDateFormat:#"yyyy.MM.dd G 'at' HH:mm:ss zzz"];
NSDateFormatter* df_local = [[[NSDateFormatter alloc] init] autorelease];
[df_local setTimeZone:[NSTimeZone timeZoneWithName:#"EST"]];
[df_local setDateFormat:#"yyyy.MM.dd G 'at' HH:mm:ss zzz"];
NSString* ts_utc_string = [df_utc stringFromDate:ts_utc];
NSString* ts_local_string = [df_local stringFromDate:ts_utc];
// you can also use NSDateFormatter dateFromString to go the opposite way
Table of formatting string parameters:
https://waracle.com/iphone-nsdateformatter-date-formatting-table/
If performance is a priority, you may want to consider using strftime
https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man3/strftime.3.html

Format date with NSDateFormatter

I want to format 06-06-2013 1:51 PM as Jun 06,2013.
I have tried all possible different formatting styles using NSDateFormatter but failed.
Try this
First You need to convert this string back to NSDate then again convert the NSdate to string using formatter.
NSDateFormatter *dateFormatForDB = [[NSDateFormatter alloc] init];
[dateFormatForDB setDateFormat:#"dd-MM-yyyy HH:mm a"]; //Note capital H is 4 24-hour time format
NSDate *aDate = [[[NSDate alloc] initWithTimeInterval:0 sinceDate:[dateFormatForDB dateFromString:aDateString]] autorelease];
if(aDate){
[formatter setDateFormat:#"MMM dd,yyyy"];
NSString *date = [formatter stringFromDate:aDate];
[dateFormatForDB release];
}
Try to use this format
[df setDateFormat:#"MMM dd,yyyy];
By looking at your format, i think this is what you are looking for...
NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setDateFormat:#"dd-MM-yyyy hh:mm a"];
NSDate *newDate = [df dateFromString:dateString];
NSDateFormatter *df2 = [[NSDateFormatter alloc] init];
[df2 setDateFormat:#"MMM dd,yyyy"];
NSString *formattedDate = [df2 stringFromDate:newDate];
This will give you the date as string in the required format. If you want time in 24hr format, replace 'hh' with 'HH'.

How to get time with date string

How can i get the time from a datetime string according to my time zone. My time zone time is +5:30 GMT.The datetime looks like-
04/03/2013 3:30:00 AM
I want the output like-
9:00:00 AM
Thanks in advance.
You need two date formatters.
One to convert string to date. And then date to string to get required in time format.
NSDateFormatter *dateFormatter=[NSDateFormatter new];
[dateFormatter setDateFormat:#"MM/dd/yyyy hh:mm:ss a"];
NSDate *date=[dateFormatter dateFromString:#"04/03/2013 3:30:00 AM"];
NSDateFormatter *dfTime = [NSDateFormatter new];
[dfTime setDateFormat:#"hh:mm:ss a"];
NSString *time=[dfTime stringFromDate:date];
*Not compiled and check
If you have date and time in string which is date time in GMT then you need to add GMT in your string. By this you can get actual time of your time zone -
NSString *dateStr = #"04/03/2013 3:30:00 AM GMT";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"MM/dd/yyyy hh:mm:ss a ZZZ"];
NSDate *date = [dateFormatter dateFromString:dateStr];
[dateFormatter setDateFormat:#"hh:mm:ss a"];
NSString *opDateStr = [dateFormatter stringFromDate:date];
NSLog(#"op = %#",opDateStr);
NSString *strdate= #"04/03/2013 3:30:00 AM";
NSDateFormatter *dateFormatter=[NSDateFormatter new];
[dateFormatter setDateFormat:#"MM/dd/yyyy hh:mm:ss a"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
NSDate *date=[dateFormatter dateFromString:strdate];
NSDateFormatter *dfTime = [NSDateFormatter new];
[dfTime setDateFormat:#"hh:mm:ss a"];
NSString *time=[dfTime stringFromDate:date];
NSLog(#"%#",time);
NSDateFormatter * formatter = [[NSDateFormatter alloc]init];
[formatter setDateFormat:#"dd/MM/yyyy hh:mm:ss a"];
NSLog(#"%#",[formatter stringFromDate:[NSDate date]]);
Output
06/03/2013 10:41:18 AM
[formatter setDateFormat:#"hh:mm:ss a"];
NSLog(#"%#",[formatter stringFromDate:[NSDate date]]);
Output
10:41:18 AM
instead of [NSDate date] pass the required date to be formatted.
As you want the time from the time string you provided according to the current time zone, you need to do something like this
NSDateFormatter *dateFormatter=[NSDateFormatter new];
[dateFormatter setDateFormat:#"MM/dd/yyyy hh:mm:ss a zzz"];
NSDate *date=[dateFormatter dateFromString:#"04/03/2013 3:30:00 AM 0000"];
NSDateFormatter *dfTime = [NSDateFormatter new];
[dfTime setTimeZone:[NSTimeZone systemTimeZone]];
[dfTime setDateFormat:#"hh:mm:ss a"];
NSString *time=[dfTime stringFromDate:date];
NSLog(#"%#",time);
you wont get the real output unless there is the offset present which is the 0000.(its the GMT offset). Also the time formatter wont work perfectly if the format of the dateString and its formatter are different. So you need to do it MM/dd/yyyy hh:mm:ss a zzz, zzz is the offset. Now your output will be 09:00:00 AM

Get the time and date of selected time zone?

I tried below snippet I'm getting current date and time of system instead of the selected time zone code.
NSDate *now = [NSDate date];
NSCalendar *gregorian=[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
[gregorian setTimeZone:[NSTimeZone timeZoneWithName:selectedzone]];
NSDateComponents* timeZoneComps = [gregorian components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSHourCalendarUnit|NSMinuteCalendarUnit|NSSecondCalendarUnit|NSTimeZoneCalendarUnit fromDate:now];
NSDate *selectedDate=[gregorian dateFromComponents:timeZoneComps];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateStyle:NSDateFormatterFullStyle];
[formatter setDateFormat:#"dd-MM-yyyy HH:mm:ss "];
NSString *strSelectedDate= [formatter stringFromDate:selectedDate];
setZone.text = strSelectedDate;`
Any ideas?
[NSDate date]returns a date object representing the current date and time, no matter where you are. NSDates are not subject to places or time zones. There is just one NSDate that represents now or any other moment for that matter, not different date objects for every time timezone. Therefore, you should not attempt to convert a date between time zones.
NSDate objects represent an absolute instant in time. Consider the following example of how two date representations in different time zones (9/9/11 3:54 PM in Paris and 9/9/11 11:54 PM in Sydney) are actually the same date.
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateStyle:NSDateFormatterShortStyle];
[formatter setTimeStyle:NSDateFormatterShortStyle];
[formatter setTimeZone:[NSTimeZone timeZoneWithName:#"Europe/Paris"]];
NSDate *aDate = [formatter dateFromString:#"9/9/11 3:54 PM"];
[formatter setTimeZone:[NSTimeZone timeZoneWithName:#"Australia/Sydney"]];
NSDate *anotherDate = [formatter dateFromString:#"9/9/11 11:54 PM"];
NSLog(#"%#",anotherDate);
if ([aDate isEqualToDate:anotherDate]) {
NSLog(#"How about that?");
}
When it comes to output a date, bear in mind that NSDate's description method returns time in GMT and you need to use a NSDateFormatter to create a date string representing the local time in Paris, Sydney, etc. from a date:
NSDate *now = [NSDate date];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateStyle:NSDateFormatterShortStyle];
[formatter setTimeStyle:NSDateFormatterShortStyle];
[formatter setTimeZone:[NSTimeZone timeZoneWithName:#"Australia/Sydney"]];
NSLog(#"%#",[formatter stringFromDate:now]); //--> 9/9/11 11:54 PM
[formatter setTimeZone:[NSTimeZone timeZoneWithName:#"Europe/Paris"]];
NSLog(#"%#",[formatter stringFromDate:now]); //--> 9/9/11 3:54 PM
[dateFormatter setDateFormat:#"EEE, d MMM yyyy HH:mm:ss z"];
Remove the trailing 'z' character from the format string if you don't want to display the time zone.
EDIT
On the other hand, if you just want to display the timezone name, just make the 'z' uppercase.
EDIT
Lowercase 'z' works fine for all the other timezones, but unfortunately GMT is a special case. So the easiest thing to do is to just omit the 'z' and append " GMT" to the formatted date.

NSString to NSDate returns wrong date

I try to convert my NSString to NSDate object, but NSDateFormatter returns me a strange value.
Here is code:
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd HH:mm"];
NSDate *date = [dateFormat dateFromString:#"2012-08-15 00:00"];
[dateFormat release];
date value is 2012-08-14 21:00 +0000. It is 3 hours difference between NSString value and NSDate value. I think I've missed something, but I don't know what.
This is what i use:
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd HH:mm:ss ZZZ"];
NSDate *date = [dateFormat dateFromString:#"2012-08-15 00:00:00 +0000"];
NSLog(#"\n\n DATE: %# \n\n\n", date);
The +0000 is timezone, so make sure you use your timezone, like +0400.
Edit:
If you can't change the string, you can use this code to do it:
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd HH:mm"];
[dateFormat setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
NSDate *date = [dateFormat dateFromString:#"2012-08-15 00:00"];
As i knew NSDate holds Grinwich time, so if you are in Moscow time zone, everything is wright
In objective c for NSDate if you did not set the setTimeZone, NSDate will take default timezone as localTimeZone. so if you need to get the exact date which you give as NSString string format, you need to setTimeZone as UTC. Follow the sample code, I guess it will be helpful for you.
NSDateFormatter *loacalformatter=[[NSDateFormatter alloc]init];
[loacalformatter setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
NSDate *localDate =[loacalformatter dateFromString:#"2012-08-15 00:00"];
NSLog(#"localDate :%#",localDate);
NSDateFormatter *UTCformatter=[[NSDateFormatter alloc]init];
[UTCformatter setTimeZone:[NSTimeZone timeZoneWithName:#"UTC"]];
[UTCformatter setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
NSDate *UTCDate =[UTCformatter dateFromString:#"2012-08-15 00:00"];
NSLog(#"UTCDate :%#",UTCDate);
UTCDate :2012-08-15 00:00 +0000 (GMT+00:00)
As suggested in the comments, if the date you receive is UTC then you need to convert it to your local timezone. Apple recommend you always use a properly configured NSDateFormatter when displaying dates, to handle localisation issues.
Here's some example code for turning an NSDate into an NSString:
NSDate *date = // initialised elsewhere
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
dateFormat.locale = [NSLocale currentLocale];
dateFormat.timeZone = [NSTimeZone localTimeZone];
dateFormat.timeStyle = NSDateFormatterShortStyle;
dateFormat.dateStyle = NSDateFormatterShortStyle;
dateFormat.locale = [NSLocale currentLocale];
NSString *dateAsString = [dateFormat stringFromDate:date];