title: How to switch between different views in a UITabbarViewController
body: <p>I tried to use the below code to do the switch:</p>
  
  <pre><code> [self.tabBarController setSelectedIndex:1];
  </code></pre>
  
  <p>I notice when I put this in  viewDidLoad ... nothing happened. But when I put in separate method, for example, when a button is clicked, it works. </p>
  
  <p>any body know why?</p>