title: how to implement loading more for table view when scroll to bottom?(i.e. pull up to refresh)
body: <p><img src="https://i.stack.imgur.com/lHTxx.png" alt="enter image description here"></p>
  
  <p>I want to load more data when view scroll to bottom,i.e. pull up to refresh, but I don't know how to display words like "Loading More..." as showing below and stop the tableview at that cell, because if use         </p>
  
  <pre><code>NSIndexPath *indexPath = [NSIndexPath indexPathForRow:10 inSection:0];
  [self.tableView scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionBottom animated:YES];
  </code></pre>
  
  <p>there's an error:</p>
  
  <p><code>*** Terminating app due to uncaught exception 'NSRangeException', reason: '-[TNTableView _contentOffsetForScrollingToRowAtIndexPath:atScrollPosition:]: row (10) beyond bounds (0) for section (0).'</code></p>
  
  <p>and if there's no data for tableView, loading more is still at the bottom cell, e.g. a table can show 9 rows, if there's no data for tableview, the "Loading More" cell is at the 10th row.</p>