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 would like to supplement Matthew's answer with a code to set-up fixed margin.

1. Subclass UITableViewCell.
2. Implement setFrame:

- (void)setFrame:(CGRect)frame
{
    CGFloat inset = 15.0;
    CGFloat tableWidth = 400.0;
    frame.origin.x -= [self groupedCellMarginWithTableWidth:tableWidth] - inset;
    frame.size.width = frame.size.width + 2 * ([self groupedCellMarginWithTableWidth:tableWidth] - inset);
    [super setFrame:frame];
}

This will set left and right margin for 15.0 while table width may vary.