title: How to know if the navigation drawer is open in Xamarin?
body: <p>I have a <code>NavigationDrawer</code> on my Main and when I press the Back button (with the <code>NavigationDrawer</code> open) the application quits, I want it to just close the <code>NavigationDrawer</code>. In Java, Android has this:</p>
  
  <pre><code>@Override
  public void onBackPressed()
  {
    if (DrawerLayout.isDrawerOpen(Gravity.START))
      DrawerLayout.closeDrawer(Gravity.START);
    else
      super.onBackPressed();
  }
  </code></pre>
  
  <p>How to make this in Xamarin.Android?</p>