Reputation: 2330

Filter dates which are earlier than today?

In my application I have a list of NSDate instances. At one point I need to seperate the dates which are past to today ie [NSDate date] (earlier to morning 12) And I have used the logic like below. I feel there must be a better logic than this, so help me if there is better solution.

I pass the date instance as an argument to this method which will return a BOOL value corresponding to my requirement.

-(BOOL)checkIfPast:(NSDate *)date
{
    NSDate *today=[NSDate date];
    NSUInteger dateFlags = NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit;
    NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSDateComponents *components1=[gregorianCalendar components:dateFlags fromDate:today];
    NSDateComponents *components2=[gregorianCalendar components:dateFlags fromDate:date];
    if (components2.day-components1.day<0) {
        return YES;
    }
    else
    {
        return NO;
    }
}

Upvotes: 1

Answers (3)

Nikolai Ruhe

Reputation: 81858

BOOL checkIfTodayOrFuture(NSDate *date)
{
    NSDate *now = [NSDate date];
    NSUInteger dateFlags = NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay;
    NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSDateComponents *components = [gregorianCalendar components:dateFlags fromDate:now];
    NSDate *midnight = [gregorianCalendar dateFromComponents:components];
    return [date compare:midnight] == NSOrderedDescending;
}

If you have to make a lot of tests keep midnight around and just do the compare: on all of the dates.

Keep in mind that the result is not constant. For example, the user might change her timezone so the interval of "today" also changes.

Upvotes: 2