NSString to NSDate conversion problem: always the same date!

Here is my class method for parsing a NSString to a NSDate object. Here is the code:

+ (NSDate *) stringToDate:(NSString *) string {
    NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss.AAA Z"];

    NSDate *date = [dateFormatter dateFromString:string];
    NSLog(@"stringToDate(\"%@\") = '%@'", string, date);
    [dateFormatter release];
    return date;
}

and running it i 开发者_如何学运维get the following output:

stringToDate("2011-07-07 16:26:07.000 +0200") = '2011-07-06 22:00:00 +0000'
stringToDate("2011-07-07 16:26:17.000 +0200") = '2011-07-06 22:00:00 +0000'

... the same output! Can you help me?

If I get you right, your problem is that the two dates are not exactly the same.

If this is the problem, the line

[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];

is responsible for it. It is converting the given time object to GMT+00 time zone.

You should write:

NSLog(@"stringToDate(\"%@\") = '%@'", string, 
       [dateFormatter stringFromDate:date]);

Otherwise, NSLog calls the description method of your date object. Here is what the documentation says about this method:

description

Returns a string representation of the receiver.

-(NSString *)description

Return Value

A string representation of the receiver in the international format YYYY-MM-DD HH:MM:SS ±HHMM, where ±HHMM represents the time zone offset in hours and minutes from GMT (for example, “2001-03-24 10:45:32 +0600”).

As you can see, the format is not exactly the same as the one you use.

edit

Try changing the dateFormat parameter of your dateFormatter to yyyy-MM-dd HH:mm:ss Z and use [dateFormatter stringFromDate:date] to display your date.