title: check if view exists from Activity
body: <p>I have a helper method that passes in the current activity and casts it to the correct activity instance. I have an optional xml button field in the layout from the activity that may be GONE, depending on different circumstances. How can i check if the button is visible from my reference to the activity? code below.</p>
  
  <pre><code> private boolean ShowDialogIfButtonExists(BaseActivity screen)
   {
        //return true if button from activity is visible
        return false;
   }
  </code></pre>