title: Using UIScreen to drive a VGA display - doesn't seem to show the UIWindow?
body: <p>HI there,</p>
  
  <p>I'm trying to use UIScreen to drive a separate screen with the VGA dongle on my iPad.</p>
  
  <p>Here's what I've got in my root view controller's viewDidLoad:</p>
  
  <pre><code>//Code to detect if an external display is connected to the iPad.
   NSLog(@"Number of screens: %d", [[UIScreen screens]count]);
  
   //Now, if there's an external screen, we need to find its modes, itereate through them and find the highest one. Once we have that mode, break out, and set the UIWindow.
  
   if([[UIScreen screens]count] &gt; 1) //if there are more than 1 screens connected to the device
   {
    CGSize max;
    UIScreenMode *maxScreenMode;
    for(int i = 0; i &lt; [[[[UIScreen screens] objectAtIndex:1] availableModes]count]; i++)
    {
     UIScreenMode *current = [[[[UIScreen screens]objectAtIndex:1]availableModes]objectAtIndex:i];
     if(current.size.width &gt; max.width);
     {
      max = current.size;
      maxScreenMode = current;
     }
    }
    //Now we have the highest mode. Turn the external display to use that mode.
    UIScreen *external = [[UIScreen screens] objectAtIndex:1];
    external.currentMode = maxScreenMode;
    //Boom! Now the external display is set to the proper mode. We need to now set the screen of a new UIWindow to the external screen
    external_disp = [externalDisplay alloc];
    external_disp.drawImage = drawViewController.drawImage;
    UIWindow *newwindow = [UIWindow alloc];
    [newwindow addSubview:external_disp.view];
    newwindow.screen = external;
   }
  </code></pre>