iphone - dateFromString always returns null with dateformatter

Question

I have the following code:

 NSDateFormatter * df = [[NSDateFormatter alloc] init];
    [df setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    [df setTimeZone:[NSTimeZone systemTimeZone]];
    [df setFormatterBehavior:NSDateFormatterBehaviorDefault];

    [df dateFromString:@"2011-04-12 10:00:00"];

In which it always generates a null date. Why is this?

Answer 1

If the device is set to AM/PM time and requested string format is set to @"yyyy-MM-dd HH:mm:ss" dateFromString will return nil.

If you set the locale to @"en_US" conversion will return correct date.

dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setTimeZone:[NSTimeZone timeZoneWithName:@"GMT"]];
[dateFormat setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"]];
[dateFormat setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSDate *date = [dateFormat dateFromString:@"2013-02-14 09:30:00"];