viewForHeaderInSection drawing a background but only if the view is at the top of the screen

My table view controller implements the viewForHeaderInSection function to return the section labels in a custom font.

Currently we use transparent background but that doesn't look good if the cells start scrolling behind the header view.

I want to draw a transparent-to-white gradient for the header view but only for the one stuck at the top.

Obviously if(section==0) would not work.

开发者_如何学CIs there a trick for this?

sometimes it's better to think for a second before posting to stack overflow. Here is the solution I found for the record. I hope it helps somebody.

        NSArray * visibleIndexes = [tableView indexPathsForVisibleRows];
        NSIndexPath * firstVisibleIndex = [visibleIndexes objectAtIndex:0];
        if (section == firstVisibleIndex.section) {
            // configure the header at the top
        }
        else {
            // configure other headers
        }