How to convert time in 24 hr format in iphone? - iphone

Question

I have to convert the given time in 24 hr format.But I did not get it.Don't know where I m going wrong.
If I have TimeStart as 1:15 PM then I should get 13:15 ..
Item *item=[sectionItems objectAtIndex:itemId];
NSLog(#"%#",item.TimeStart);
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"HH:mm a"];
NSString *formattedDateString = [dateFormatter stringFromDate:item.TimeStart];
NSLog(#"%#",formattedDateString);
In the code above I have a Item class and that I have NSString *TimeStart;
When I see formattedDateString it is returning null.How can I fix it ?

Answer 1

Item *item=[sectionItems objectAtIndex:itemId];
NSLog(#"%#",item.TimeStart);
NSString *str = #"1:45.PM";// put here item.TimeStart
NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setDateFormat:#"hh:mm.a"];// here give the format which you get in TimeStart
NSDate *date = [dateFormatter dateFromString: str];
dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setDateFormat:#"HH:mm"];
NSString *convertedString = [dateFormatter stringFromDate:date];
NSLog(#"Converted String : %#",convertedString);

Answer 2

i just simply setDateFormat like [formatter setDateFormat:#"HH:mm"]; Remove a
and below caode for checking its time formate is 24 hr or 12
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setLocale:[NSLocale currentLocale]];
[formatter setDateStyle:NSDateFormatterNoStyle];
[formatter setTimeStyle:NSDateFormatterShortStyle];
NSString *dateString = [formatter stringFromDate:[NSDate date]];
NSRange amRange = [dateString rangeOfString:[formatter AMSymbol]];
NSRange pmRange = [dateString rangeOfString:[formatter PMSymbol]];
BOOL is24h = (amRange.location == NSNotFound && pmRange.location == NSNotFound);
[formatter release];
NSLog(#"%#\n",(is24h ? #"YES" : #"NO"));

Answer 3

Use this to set 24 hr format.
[currentDate setDateFormat:#"yyyy-MM-dd HH:mm"];
or
[formatter setDateFormat:#"HH:mm"];
without using formatter
NSRange range;
range.location = 2;
range.length = 2;
NSString *dateString=[NSString stringWithFormat:#"%#:%#",[myString substringToIndex:2], [myString substringWithRange:range]];
This is the code i am using in my project and its working for me
NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setDateFormat:#"HH:mm"];
NSString *dateString = [dateFormatter stringFromDate:[NSDate date]];
NSLog(#"Current time date:%#", dateString);
output:Current time date:14:41