title: Kill fragment in navigation controller
body: <p>My flow of fragment is like this</p>
  
  <pre><code>Main -&gt; A -&gt; B -&gt; C -&gt;A
  </code></pre>
  
  <p>In fragment c, it has a submit button which will return to A. 
  When I press back button in A, I want it back to Main. But it return to fragment c instead.</p>
  
  <p>In fragment C, I use this</p>
  
  <pre><code> findNavController().navigate(R.id.action_c_to_a)
  </code></pre>
  
  <p><strong>nav_graph.xml</strong></p>
  
  <pre><code> &lt;fragment
          android:id="@+id/fragmentC"
          android:name="xxx"
          android:label="xxx"&gt;
          &lt;action
              app:launchSingleTop="true"
              app:popUpTo="@+id/fragmentA"
              app:popUpToInclusive="true"
              android:id="@+id/action_c_to_a"
              app:destination="@id/fragmentA" /&gt;
      &lt;/fragment&gt;
  </code></pre>