title: Navigation View - update item checked on back button press
body: <p>I made a NavigationView on MainActivity (AppCompatActivity). 
  I have multiple items on that NavigationView each one is a Fragment.</p>
  
  <p>When I use back button I want to go to previous Fragment instead of put my app on background. Thus to change between Fragments I use:</p>
  
  <pre><code>       FragmentManager fragmentManager = getSupportFragmentManager();
         fragmentManager.beginTransaction().replace(R.id.layout, fragment).addToBackStack(null).commit();
  </code></pre>
  
  <p>When I press back button it goes to the previous Fragment, but the item checked of NavigationView remains. Which is the best way to update item checked of NavigationView on back button press?</p>