code: public boolean onOptionsItemSelected(MenuItem item) {
          if (item != null && item.getItemId() == android.R.id.home && mDrawerIndicatorEnabled) {
              toggle();
              return true;
          }
          return false;
      }
docs: This method should be called by your <code>Activity</code>'s
  {@link Activity#onOptionsItemSelected(android.view.MenuItem) onOptionsItemSelected} method.
  If it returns true, your <code>onOptionsItemSelected</code> method should return true and
  skip further processing.
  
  @param item the MenuItem instance representing the selected menu item
  @return true if the event was handled and further processing should not occur