title: Navigation arrow is not displayed on actionbar on left which acts as back - android
body: <p>I am using actionbar in my application.
  I add backbutton on actionbar. On its click back function is called.
  But left arrow which is usually displayed on actionbar is not getting displayed.</p>
  
  <p>I am trying with following code:</p>
  
  <pre><code>getActionBar().setDisplayOptions(ActionBar.DISPLAY_HOME_AS_UP, ActionBar.DISPLAY_HOME_AS_UP);
  </code></pre>