NSPredicate filtering with NSManagedObject's helper method

I have a UITable view which contains a list of NSManagedObjects called Assignment. I am using NSPredicate to filter the list. I am filtering assignments that should be shown for today and yesterday for a player:

NSPredicate *predicate = [NSPredicate predicateWithFormat:
                          @"player == %@ AND (day == %@ OR day == %@)", 
                          player, 
                          [NSNumber numberWithInt:[self todaysDayNumber]],
                          [NSNumber numberWithInt:[self yesterdaysDayNumber]]];

I need to add an additional level of filtering. I want to filter out assignments that should only be shown biweekly. So I added this methods to Assigment: 开发者_如何学编程

-(BOOL)thisWeeks{
  //If this is a weekly assigment
  if ([self.weekly boolValue]) {
    return YES;
  }

  //Determine the week number
  NSCalendar *calendar = [NSCalendar currentCalendar];
  NSUInteger unitFlags = NSWeekCalendarUnit;
  NSDateComponents *dateComponents = [calendar components:unitFlags 
                                                 fromDate:[NSDate date]];
  NSUInteger week = [dateComponents week];

  //Assigned week even?
  if ([self.weekNumber intValue] % 2){
    //Current week even?
    if (week % 2) {
        return YES;
    }  
  } 
  //Assigned week odd?
  if (!week % 2) {
  //Current week odd?
    if (![self.weekNumber intValue] % 2){
      return YES;
    }
  }
//Should not be shown this week.
return NO;
}

is it possible to use this helper method "thisWeeks" as a filter in NSPredicate?

If I'm "doing it wrong", I could manually filter the fetched results, but I am unsure as to how I would put the results back into NSFetchedResultsController such that my UITable view could continue using NSFetchedResultsController.

---

NSPredicate also accepts blocks as predicates. Here an example with the first check in thisWeeks:

NSPredicate *predicate = [NSPredicate predicateWithBlock:^BOOL(id obj, NSDictionary *bind) {
    return [self.weekly boolValue];
}];

Now you can implement the method - (BOOL)thisWeeksWithObject:(id)object and write this:

NSPredicate *predicate = [NSPredicate predicateWithBlock:^BOOL(id obj, NSDictionary *bind) {
    return [self thisWeeksWithObject:obj];
}];

Sure, you have to change the self in the method to object.