没时间NSDate

Question

I have written the following method:

- (NSDate *)stringToDate:(NSString *)dateString
{
    // Convert string to date
    NSDateFormatter * dateFormat = [[NSDateFormatter alloc] init];
    NSTimeZone *tz = [NSTimeZone timeZoneWithName:@"America/New_York"];
    [dateFormat setDateFormat:@"M/d/yyyy HH:mm:ss"];
    [dateFormat setTimeZone:tz];
    NSDate * date = [dateFormat dateFromString:[NSString stringWithFormat:@"%@ 00:00:00", dateString]];

    return dateOnly;
}

When I call this with just a date such as 11/1/2013 or 11/13/2013 I get 2013-11-01 04:00:00 +0000 and 2013-11-13 05:00:00 +0000.

If I set a breakpoint on the return the date appears right, but if I break at in the calling function after this call, the date is returned with the time.

How come my time is not always 0. Can anyway tell me what is wrong in my function?

Thank you

UPDATE:

The input string is as follows: 11/1/2013 and 11/13/2013

Answer 1

NSDate is a point in time. It will always have a time component.
And if not printed as a string form a NSDateFormatter, the Date and time will always be the one of UTC/GMT.

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The format and the date string must fit.

NSString *dateString = @"11/1/2013";
[dateFormat setDateFormat:@"M/d/yyyy"];

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The one hour apart comes from the Daylight saving time. Till November, 3rd 2013 New York has Summer time. http://www.timeanddate.com/worldclock/clockchange.html?n=179

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Ok, so can I ignore that? I am trying to compare NSDates when I do my comparison fails because of the time part

You should create dates with with a time during the day — ie noon — to be save of DST mess and compare those. Use NSComponents for that.

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A must-see for any iOS/Cocoa-Developer: the fantastic WWDC 2011 Video "Session 117 - Performing Calendar Calculations" .