Question

I am writing a categorie in Xcode, that would extend the current NSDate class. I want to add two methods which I use regularly and somehow I can’t get them to work properly.

Currently I have this code:

+ (NSDate*) today
{
    NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

    NSDateComponents *todayComponents = [gregorian components:(NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit) fromDate:[NSDate date]];
    NSInteger theDay = [todayComponents day];
    NSInteger theMonth = [todayComponents month];
    NSInteger theYear = [todayComponents year];

    NSDateComponents *components = [[NSDateComponents alloc] init];
    [components setDay:theDay]; 
    [components setMonth:theMonth]; 
    [components setYear:theYear];

    NSDate* todayDate = [gregorian dateFromComponents:components];

    [components release];
    [gregorian release];

    return todayDate;
}

I want it to return a date like this: “2010-11-03 00:00:00 +01”. But somehow the timezone keeps buggin me, because this code returns “2010-11-02 23:00:00 +0000”.

Can anyone tell me how to fix this code to actually return the correct date? Or can I just use this date and my application will convert it itself because of the timezone the machine is set to.

I have to log certain events in my app to a database, which also just uses the [NSDate date] method. Does that mean that the [NSDate date] method also uses the time without timezone information?

EDIT:
I think it has something to do with the Daylight savings time bug. The things I see is exactly the same as probably the Clock app has, with the bug making people wake up late. Also, the TimeZone defaults to the TimeZone currently set on your device, so it should stay the same until you change the timezone in your settings screen.

EDIT2:
Ok, some more tests:

NSLog(@"CurrentDate: %@", [NSDate date]);
NSLog(@"TZ: %@", [NSTimeZone defaultTimeZone]);

Gives me the following results:

2010-11-03 23:23:49.000 App[8578:207] CurrentDate: 2010-11-03 22:23:49 +0000
2010-11-03 23:23:49.001 App[8578:207] TZ: Europe/Amsterdam (GMT+01:00) offset 3600

Answer 1

See Using Time Zones. You’ll want to set the calendar’s time zone using NSCalendar’s -setTimeZone: method before you start asking it for dates.