title: Customize accessibility message - 3 fingers tap on UIPageViewController
body: <p>I am working on an eBook reader book application where i am using UIPageViewController to provide the pageCurl effect. UIPageViewController is configured with 3 viewControllers to display the book content and it is configured to support the accessibility.</p>
  
  <p>When the accessibility is enabled, Three fingers tap on the reader page plays the announcement as "Center of Screen". I would like customize the message like "Page x of y". </p>
  
  <pre><code>- (BOOL)isAccessibilityElement
  {
      return YES;
  }
  
  - (UIAccessibilityTraits)accessibilityTraits
  {
      return UIAccessibilityTraitCausesPageTurn;
  }
  </code></pre>
  
  <p>The following properties/functions are also set</p>
  
  <ol>
  <li>accessibilityPageContent</li>
  <li>accessibilityLabel </li>
  <li>accessibilityLineNumberForPoint</li>
  <li>accessibilityContentForLineNumber</li>
  <li>accessibilityFrameForLineNumber</li>
  <li>accessibilityFrame</li>
  </ol>
  
  <p>I don't see apple accessibility documentation to handle the 3 fingers tap.</p>
  
  <p>How to customize the accessibility message on 3 fingers Tap?</p>