Checking if a date is of the same calendar day

Question

Could someone please help me figure out how to check if some date is of the same day as today. I guess it would require creating a calender day at 0 hour of the same day in the same timezone and checking against that, but so far my attempts have confused me more then anything.

Answer 1

You should take a good read through this Dates and Times Programming Topics for Cocoa, but something like this should work:

NSDate *today = [NSDate date];
NSTimeInterval difference = [today timeIntervalSinceDate:otherDate];
NSTimeInterval secondsPerDay = 24 * 60 * 60;
if (difference < secondsPerDay)
{
   //same day as today
}

Answer 2

NSCalendar lets you deal with human days. So you could implement a category something like this:

@implementation NSDate (IsItToday)
- (BOOL)isToday {
    NSUInteger desiredComponents = NSEraCalendarUnit|NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit;
    NSDateComponents *myCalendarDate = [[NSCalendar currentCalendar] components:desiredComponents fromDate:self];
    NSDateComponents *today = [[NSCalendar currentCalendar] components:desiredComponents fromDate:[NSDate date]];
    return [myCalendarDate isEqual:today];
}
@end