Managing where rows can be moved to in UITableView

In an app I was working on, I needed to prevent users from moving rows from section 1 to section 0. After reading the docs, I found Apple has just the API: Reordering Table Rows.

Here’s how I used the API. If the proposed destination section is 0, then return the current indexPath. As a result the user will be unable to draw a row from section 1 to section 0.

func tableView(tableView: UITableView, targetIndexPathForMoveFromRowAtIndexPath sourceIndexPath: NSIndexPath, toProposedIndexPath proposedDestinationIndexPath: NSIndexPath) -> NSIndexPath
{

if proposedDestinationIndexPath.section == 0 {
return sourceIndexPath
}

return proposedDestinationIndexPath;
}

My problem was simple, but this API could be used for all kinds of reordering problems.