title: How to refresh UIView
body: <p>I get one problem is that,</p>
  
  <p>This's <code>showads</code> function.</p>
  
  <pre><code>[self.mMainView addSubview:adViewController.view];
  //...(my function to display ads)
  </code></pre>
  
  <p>This's <code>hideads</code> function.</p>
  
  <pre><code> //...(my function to hide ads)
   [[AdViewController sharedAdViewController].view removeFromSuperview];
   [self.mMainView setNeedsDisplay];
  </code></pre>
  
  <hr>
  
  <p>The <code>mMainView</code> is a <code>UIView</code>.
  The <code>AdViewController</code> is a <code>UIViewController</code>.</p>
  
  <p>The problems is that after calling <code>showads</code> fucntion, the my ads display on <code>mMainView</code>. But after calling <code>hideads</code> function, the my ads don't disappear, it still appear on <code>mMainView</code>.</p>
  
  <p>Note: After calling <code>hideads</code> and make an interrupt then resume the app, the my ads will disappear.</p>
  
  <p>So, i want to remove it, could you please explain a bit in more detail and show me how to fix it if you can pls ?</p>