title: How can I set alpha to the navbar but except children (Back button, title etc.)?
body: <p>I have to set alpha to the navbar, and I do it by <code>self.navigationController.navigationBar.alpha = 0.2f;</code> </p>
  
  <p>The problem is that buttons and title have alpha as the navbar.</p>
  
  <p>I understand the problem but I don't know how to fix it.</p>
  
  <p>Could anybody help me?</p>
  
  <p>Thanks</p>