title: How to know if a Fragment is Visible?
body: <p>I'm using the support library v4 and my questions are, How to know if a Fragment is Visible? and How can I change the propierties of the Layout inflated in the Fragment? Thanks in advance.</p>
  
  <p>---Edit---</p>
  
  <p>I'm using fragments like in the android developers tutorial with a FragmentActivity</p>