title: How to force screen update for UIScrollView from non-UI thread/function (iPhone)
body: <p>I am drawing a set of images on the uiscrollview from a non-ui thread/function. But its only displayed after all the images are done drawing. For drawing all the images, I have written a function and that is what is being called as the non-ui thread. I did write this line inside the function</p>
  
  <pre><code>[self performSelectorOnMainThread:@selector(updateUI) withObject:nil waitUntilDone:NO];
  </code></pre>
  
  <p>And have written the function as given below</p>
  
  <pre><code>- (void)updateUI
  {
  [myScrollView setNeedsDisplay];
  }
  </code></pre>
  
  <p>But its having no effect even when I can see the control being passed to that function. What to do now?</p>