title: Android action bar hide and show on top-down swipe
body: <p>I'm developing an Android fulscreen activity, and I would like to be able to show and hide the Action Bar exactly like I'm doing with the navigation menu.</p>
  
  <p>Currently I have set only the setSystemUiVisibility and </p>
  
  <pre><code>getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY                        
  | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION); 
  </code></pre>
  
  <p>an this to permanently hide the action bar:</p>
  
  <pre><code>android.app.ActionBar actionBar = getActionBar();
  actionBar.hide();
  </code></pre>
  
  <p>But how can I get it to slide when the user swipes from the top down, like the navigation bar does?</p>