Get the two NSDate
values from the pickers. Then do:
NSDate *date1 = // first date
NSDate *date2 = // second date
NSTimeInterval diff = fabs([date1 timeIntervalSinceDate:date2]);
if (diff > 3 * 60) {
// the difference is more than 3 minutes
}
Another options would be:
NSDate *date1 = // first date
NSDate *date2 = // second date
unsigned int unitFlags = NSMinuteCalendarUnit;
NSDateComponents *comps = [gregorian components:unitFlags fromDate:date1 toDate:date2 options:0];
int minutes = [comps minute];
if (minutes > 3) {
// the difference is more than 3 minutes
}