title: setting an accessibilityLabel on a UIImageView contained in UITableView header
body: <p>I have a <code>UITableView</code> that I build in <code>loadView</code>. One of the things I do in <code>loadView</code> is create a <code>UIView</code> to act as the table header and stuff a <code>UIImageView</code> into it. The image view contains an image that is a stylized title, so I want to add an accessibility label for VoiceOver users. However, I can't get VoiceOver to "focus" on the image in order to read the label, and the Accessibility Inspector doesn't respond to clicking on the image in the simulator. My (abbreviated) code follows:</p>
  
  <pre><code>... in -loadView ...
  // Make header view
  UIView *headerView = [[UIView alloc] initWithFrame:CGRectMake(...)];
  UIImageView *titleImageView = [[UIImageView alloc] initWithImage:[self titleImage]];
  titleImageView.accessibilityLabel = [self accessibilityLabelForTitleImage];
  [headerView addSubview:titleImageView];
  
  // Make table view
  self.tableView = [[UITableView alloc] initWithFrame:CGRect(...) style:UITableViewStylePlain];
  self.tableView.tableHeaderView = headerView;
  ... code continues ...
  </code></pre>
  
  <p>I've stepped through in gdb and <code>accessibilityLabelForTitleImage</code> returns a string. <code>po [titleImageView accessibilityLabel]</code> prints out the correct string, but I'm still unable to focus on the image view. Note that the views themselves appear and respond as appropriate.</p>
  
  <p>Am I missing something? Is there a way to force VoiceOver to acknowledge an image view?</p>