How to determine margin of a grouped UITableView (or better, how to set it)?

Question

The grouped UITableView places a margin between the edge of the view and the table cells. Annoyingly (for me) this margin is some function of the width of the view.

Answer 1

I have tried a different approach. But not sure whether it always work. I had a grouped UITableView and needed to make customized Header View. But as you know, when implementing viewForHeader inSection method we can not determine the margins for our created view. So, what I have done is firstly add a CGRect property to ViewController .m file:

@property(nonatomic)CGRect groupedCellRectangle;

and in UITableViewDelegate:

-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath{
    static BOOL groupFrameInitialized = NO;
    if(!groupFrameInitialized){
        groupFrameInitialized = YES;
        self.groupedCellRectangle = cell.contentView.frame;
    }
}

after then, in my viewForHeader inSection method:

-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section{
  UIView *v = [[UIView alloc] initWithFrame:CGRectMake(self.groupedCellRectangle.origin.x, 0, self.groupedCellRectangle.size.width, 28)];
  [v setBackgroundColor:[UIColor clearColor]];
  UILabel *label = [[UILabel alloc] initWithFrame:v.frame];
  label.text = @"KAF";
  [v addSubview:label];
  return v;
}

the result is as I assumed. groupedCellRectangle had successfully stored CGRect value with margin.

The idea behind this approach was UITableView always call viewForHeader method after willDisplay call.

Hope that helps...