Question

I’m trying to format a NSDate to a string with date format of yyyyMMdd, here’s the code

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"yyyyMMdd"];

NSDate *date =data.createdTime;

NSLog(@"%@",date);
NSLog(@"%@",[dateFormatter stringFromDate:date]);

the NSLog return me this value

Tue, 24 May 2011 0:05:01 +0800
(null)

Anyone know which part is wrong?

Thanx in advance.

Answer 1

Perhaps currentArticle.createdTime is a valid date but data.createdTime is nil? In addition, you are performing the -setDateFormat: selector on dateFormat, but it seems like your date formatter is dateFormatter.

Try the following code:

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat: @"yyyyMMdd"];

NSDate *date = data.createdTime;

NSLog(@"   Normal Date = %@", date);
NSLog(@"Formatted Date = %@", [dateFormatter stringFromDate: date]);

[dateFormatter release];

If date is nil, then both NSLog() calls will tell you.

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Edit

Double check that data.createdTime is an NSDate instance. Perhaps it is an instance of another class, such as NSString, whose -description returns the displayed date. This would explain why NSLog() “shows” the date, but the formatter is returning nil.

BOOL isDate = [data.createdTime isKindOfClass: [NSDate class]];
NSLog(@"Date %@ a date.", isDate ? @"is" : @"is not");