title: How to add a drop shadow to a UIButton?
body: <p>I would like to add a drop shadow to a UIButton. I tried to use self.layer.shadow* properties. Those properties work in UIView, but they behave differently in UIButton. I would really appreciate it if I could get any pointers to draw the drop shadow. Thank you!</p>
  
  <pre><code>self.layer.cornerRadius = 8.0f;
  self.layer.masksToBounds = YES;
  self.layer.borderWidth = 1.0f;
  
  self.layer.shadowColor = [UIColor greenColor].CGColor;
  self.layer.shadowOpacity = 0.8;
  self.layer.shadowRadius = 12;
  self.layer.shadowOffset = CGSizeMake(12.0f, 12.0f);
  </code></pre>