title: iOS TabbarViewController hide the tab bar
body: <p>I have a viewcontroller that it implement UITabbarViewController, and I want to hide
  the tab bar and override it by myself, </p>
  
  <pre><code>self.tabBar.hidden = YES;
  </code></pre>
  
  <p>the tab bar disappeared BUT there is a blank area(the blue one) at the bottom of the view.
  I dont want the blank area , how can I fix this? Thank you. </p>
  
  <p>edit: the blue area is:</p>
  
  <pre><code>self.view.backgroundColor = [UIColor blueColor];
  </code></pre>