Question

I am new to core data and NSFetched resultcontroller. So far I managed to fill up my tableView. But now I want to divided into sections. Here is how my code looks like.

- (void)getKeepers // attaches an NSFetchRequest to this UITableViewController
{

    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Team"];
    request.sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"sortOrder" ascending:YES]];
    self.fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:request
                                                                        managedObjectContext:self.genkDatabase.managedObjectContext
                                                                          sectionNameKeyPath:nil
                                                                                   cacheName:nil];

}

Let me sketch the situation. I am making an app for a football club. In my tableview I want for every position (goalkeeper,defender,winger,attacker) a new section. My core database looks like this.

- TEAM
   -name
   -Position
   -img_url
   -birthDate
   -sortOrder

I added the attribute sortOrder to sort my players. But can anybody help me to divide it into sections?

Thanks in advance !!

WHAT I DO IN MY CELL_FOR_ROW_AT_INDEX
In my cellForRowAtIndex I am doing not the usual thing. I am working with a custom tableviewCell which contains 6 imageviews. But its possible that a row only contains 4 images. You can see what I am trying to do over here.

#define IMAGES_PER_ROW  6

   NSInteger frcRow = indexPath.row * IMAGES_PER_ROW; // row in fetched results controller

    for (int col = 1; col <= IMAGES_PER_ROW; col++) {
        NSIndexPath *path = [NSIndexPath indexPathForRow:frcRow inSection:0];
        Team *team = [self.fetchedResultsController objectAtIndexPath:path];
        NSData *imgData = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:team.image]];
        UIImage *image;
        if (imgData == nil) {
            // default image
            image = [UIImage imageWithContentsOfFile:@"keeperNil.jpg"];
        } else {
            image = [UIImage imageWithData:imgData];
        }
        [cell setImage:image forPosition:col];
        frcRow ++;
    }

Answer 1

Use the sectionNameKeyPath value to be the field you want to use for the sections.

Then you need these three functions…

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return [self.fetchedResultsController.sections count];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    id <NSFetchedResultsSectionInfo> sectionInfo = self.fetchedResultsController.sections[section];

    return [sectionInfo numberOfObjects];
}

- (NSString*)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
    id <NSFetchedResultsSectionInfo> sectionInfo = self.fetchedResultsController.sections[section];

    return [sectionInfo name];
}

This should be enough.

Your cellForRowAtIndexPath function should look something like this…

...
UITableViewCell* cell = [UITableViewCell dequeueCellWithReuseIdnetifier:@"blah"];

Team *team = [self.fetchedResultsController objectAtIndexPath:indexPath];

cell.textLabel.text = team.name;
cell.detailTextLabel.text = team.position.

Or something like that.

The error you are getting means you are trying to access an array that doesn’t contain enough entries.

If that doesn’t work then post your cellForRowAtIndexPath function.