title: Bar Button Item Fade In/Out?
body: <p>Is there any way to fade a bar button item, as there is no <code>.alpha</code> attribute to set. I'm interested in fading a button out and fading another button in to take its place on the navigation bar. Is there any way to do this?</p>
  
  <p>EDIT: I am trying to fade the top right <code>Bar Button Item</code></p>
  
  <p><img src="https://i.stack.imgur.com/OgYjc.png" alt="storyboard"></p>
  
  <p>I understand fading is usually accomplished with the <code>.alpha</code> as I stated before.</p>
  
  <p>My issue is for a <code>Bar Button Item</code> there is NO alpha attribute.</p>
  
  <p>As seen here: </p>
  
  <p><img src="https://i.stack.imgur.com/8fmep.png" alt="attributes of bar button"></p>
  
  <p>As opposed to a normal button where there is an <code>.alpha</code> attribute:</p>
  
  <p><img src="https://i.stack.imgur.com/gQoKm.png" alt="attributes of button"></p>
  
  <p>How can I fade a <code>Bar Button Item</code>?</p>