Detect the current top cell in a UITableView after scrolling

Question

a simple question but I don\'t seem to have the right terminology to search Stackoverflow by it.

I have a UITableView with no sections, the user can scroll up and do

Answer 1

In Swift 4:

func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
    let firstVisibleIndexPath = self.tableview.indexPathsForVisibleRows?[0]
    print("top visible cell section  is \([firstVisibleIndexPath!.section])")
}