How to clear back stack from navigation controller

Question

If I have 4 fragments (A,B,C and D) and I move from left to right to end at D, I want to clear back the stack till A.

so when using navigation graph, it may be in the action of C fragment like so:

<action
  android:id="@+id/c"
  app:destination="@+id/d"
  app:popUpTo="@id/a"
  app:popUpToInclusive="true" />

but when am doing this, the c fragment is not cleared from backstack. It means that when I click backpress from d, c is coming and then a. How do I solve this please?

Answer 1

To achieve A->B->C->D and then pressing back return to A :

Define in your navigation:

   <fragment
        android:id="@+id/c"
        ...>

        <action
            android:id="@+id/action_c_to_d"
            app:destination="@id/d"
            app:popUpTo="@+id/b"
            app:popUpToInclusive="true"/>

    </fragment>

And use:

findNavController().navigate(R.id.action_c_to_d)