title: UITableViewCell will disappear
body: <p>I made an UITableView and contained some custom UITableViewCells, in the fist cell (named cell0 for example) there are some UITextFields for input, when I scroll the tableView, cell0 will disappear from the top of screen, then How can I get the UITextField's text in cell0? </p>
  
  <p><code>cellForRowAtIndexPath</code> will return nil.</p>