How to calculate if current time is within a time span

Question

I am working on an iphone app for class and my group is having some time trouble.

The idea we are working with is that we have a scheduled event (say 2:00pm) and we want to know if we are within a certain amount of time from the scheduled time (say +/- 15 minutes). So for this example if the event was at 2pm, if this event was called from 1:45-2:15pm the method would return true/yes, and otherwise, it would return false/no.

I know how to current time/date, but how do I do the part with checking to see if it is within a certain range of time from the event time? ?

So what I am going for would be a method similar to the following with currentTime getting a NSDate object for the current time and classStartTime getting a NSDate object for the start time of the class:

- (BOOL)dateInRange:(NSDate*)currentTime inRangeOf:(NSDate*)classStartTime
{
    if([currentTime <= [classStartTime dateByAddingTimeInterval:60*15]] && [currentTime >= [classStartTime dateByAddingTimeInterval:-(60*15)]])
    {
        return TRUE;
    }
    else{
        return FALSE;
    }
}

I know this doesn't work. How do I get the comparison part of the if statement to work properly

possible duplicate of [How to Check if an NSDate occurs between two other NSDates](http://stackoverflow.com/questions/1072848/how-to-check-if-an-nsdate-occurs-between-two-other-nsdates) — jscs, Mar 24 '12 at 19:38

score 0 · Answer 1 · answered Mar 24 '12 at 19:36

0

I guess, your time is a NSDate. You could use TimeIntervalSinceDate: with the start time of your interval and check if the result is positive and smaller than your interval length.

answered Mar 24 '12 at 19:36

Matthias

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score 0 · Answer 2 · answered Mar 24 '12 at 19:38

Use NSDate and NSDateComponents. I don't have a Mac nearby, so the following code will probably have errors in it.

NSCalendar *gregorian = [[NSCalendar alloc]initWithCalendarIdentifier:NSGregorianCalendar];
int comp = NSHourCalendarUnit | NSMinuteCalendarUnit;
NSDateComponents *theDateComponents = [gregorian components:comp fromDate:[NSDate date]];
int hour = [theDateComponents hour];
int minute = [theDateComponents minute];
if ((hour == 13 && minute >= 45) || (hour == 14 && minute <= 15)) {
  //do your stuff
}

Hope it helps

Don't bother with components,bit is much easier to compare double values. — Grady Player, Mar 24 '12 at 23:27

score 0 · Answer 3 · answered Mar 24 '12 at 23:34

0

Find a start date and and end date with + (id)dateWithTimeInterval:(NSTimeInterval)seconds sinceDate:(NSDate *)date

then use the compare method to check that the date you are checking falls within your dates...

answered Mar 24 '12 at 23:34

Grady Player

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How to calculate if current time is within a time span

3 Answers3