How to hide first section header in UITableView (grouped style)

I have a workaround that seems reasonably clean to me. So I'm answering my own question.

Since 0 as the first section header's height doesn't work, I return 1. Then I use the contentInset to hide that height underneath the navigation bar.

Objective-C:

- (CGFloat) tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
    if (section == 0)
            return 1.0f;
    return 32.0f;
}

- (NSString*) tableView:(UITableView *) tableView titleForHeaderInSection:(NSInteger)section
{
    if (section == 0) {
        return nil;
    } else {
        // return some string here ...
    }
}

- (void) viewDidLoad
{
    [super viewDidLoad];

     self.tableView.contentInset = UIEdgeInsetsMake(-1.0f, 0.0f, 0.0f, 0.0);
}

Swift:

override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
    return section == 0 ? 1.0 : 32
}

override func viewDidLoad() {
    super.viewDidLoad()

    tableView.contentInset = UIEdgeInsets(top: -1, left: 0, bottom: 0, right: 0)
}

Use this trick for grouped type tableView

Copy paste below code for your table view in viewDidLoad method:

tableView.tableHeaderView = [[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, tableView.bounds.size.width, 0.01f)];

This is how to hide the first section header in UITableView (grouped style).

Swift 3.0 & Xcode 8.0 Solution

1. The TableView's delegate should implement the heightForHeaderInSection method

2. Within the heightForHeaderInSection method, return the least positive number. (not zero!)

   func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
   
       let headerHeight: CGFloat
   
       switch section {
       case 0:
           // hide the header
           headerHeight = CGFloat.leastNonzeroMagnitude
       default:
           headerHeight = 21
       }
   
       return headerHeight
   }
   

The answer was very funny for me and my team, and worked like a charm

• In the Interface Builder, Just move the tableview under another view in the view hierarchy.

REASON:

We observed that this happens only for the First View in the View Hierarchy, if this first view is a UITableView. So, all other similar UITableViews do not have this annoying section, except the first. We Tried moving the UITableView out of the first place in the view hierarchy, and everything was working as expected.