title: Copy the google plus floating toolbar menu
body: <p>I'm trying to emulate a "toolbar" type floating menu used by the android google plus app. The menu appears when you scroll up the page and hides nicely when you scroll down.</p>
  
  <p>I'm guessing this is a linear layout with some sort of animation. Is that correct? Any ideas on how to reproduce?</p>
  
  <p><img src="https://i.stack.imgur.com/bllMw.jpg" alt="Google Plus menu"></p>