title: how do you override setFrame for a UILabel
body: <p>I wanted to override setframe so that it centers the label as well, however doing something like:</p>
  
  <pre><code>- (void)setFrame:(CGRect)frame 
  {
      [self setFrame:frame};
      self.center = CGPointMake(self.superview.center.x, kNavigationBarFrameHeight/2);
  }
  </code></pre>
  
  <p>gives me an infinite loop. So how do I do this?</p>