Snippet of AccordionTableView logic

AccordionTableView.m

@synthesize selectedIndexPath;
@synthesize defaultRowHeight;
@synthesize optionRowHeight;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.optionRowHeight = 40;
    }
    return self;
}


- (void)viewDidUnload
{
    [super viewDidUnload];
    self.selectedIndexPath = nil;
}

#pragma mark - UITableViewDelegate

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (self.selectedIndexPath && self.selectedIndexPath.row + 1 == indexPath.row) {
        return optionRowHeight;
    }
    return defaultRowHeight;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (indexPath.section == self.numberOfSections) {
        return;
    }
    
    if (self.selectedIndexPath && self.selectedIndexPath.row + 1 == indexPath.row) {
        return;
    }
    
    [tableView beginUpdates];
    
    if ([self.selectedIndexPath isEqual:indexPath]) {
        
        self.selectedIndexPath = nil;
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:[NSIndexPath indexPathForRow:indexPath.row + 1 inSection:indexPath.section]] 
                         withRowAnimation:UITableViewRowAnimationBottom];
        [tableView deselectRowAtIndexPath:indexPath animated:YES];
        
    } else {
        
        NSIndexPath *oldSelectedIndexPath = self.selectedIndexPath;
        if (oldSelectedIndexPath) {
            
            [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:
                                               [NSIndexPath indexPathForRow:oldSelectedIndexPath.row + 1
                                                                  inSection:oldSelectedIndexPath.section]] 
                             withRowAnimation:UITableViewRowAnimationBottom];
            [tableView deselectRowAtIndexPath:[NSIndexPath indexPathForRow:oldSelectedIndexPath.row
                                                                 inSection:oldSelectedIndexPath.section]
                                     animated:YES];
            
        }
        
        if (!oldSelectedIndexPath ||
            [oldSelectedIndexPath compare:indexPath] == NSOrderedDescending) {
            
            // newly selected row above old selection
            self.selectedIndexPath = indexPath;
            [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:
                                               [NSIndexPath indexPathForRow:self.selectedIndexPath.row + 1
                                                                  inSection:indexPath.section]] 
                             withRowAnimation:UITableViewRowAnimationBottom];
            
        } else {
            
            // newly selected row below old selection
            [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:
                                               [NSIndexPath indexPathForRow:indexPath.row
                                                                  inSection:indexPath.section]] 
                             withRowAnimation:UITableViewRowAnimationBottom];
            self.selectedIndexPath = [NSIndexPath indexPathForRow:indexPath.row - 1 inSection:indexPath.section];
            
        }
        
        [tableView scrollToRowAtIndexPath:self.selectedIndexPath atScrollPosition:UITableViewScrollPositionNone animated:YES];
    }
    
    [tableView endUpdates];
}