Why Android Navigation Component screen not go back to previous Fragment,but a method in onViewCreated of previos Fragment being called?

Question

I have 2 fragment call CreateRoomFragment and DisplayPhotoFragment,the navigation graph is look like this:

<navigation>    
<fragment
    android:id="@+id/createRoomFragment"
    android:name="package.room.CreateRoomFragment"
    android:label="Create a room"
    tools:layout="@layout/fragment_create_room">
    <action
        android:id="@+id/action_createRoomFragment_to_roomFragment"
        app:destination="@id/roomFragment" />
    <action
        android:id="@+id/action_createRoomFragment_to_displayPhotoFragment"
        app:destination="@id/displayPhotoFragment" />
</fragment>

<fragment
    android:id="@+id/displayPhotoFragment"
    android:name="package.fragment.DisplayPhotoFragment"
    android:label="fragment_display_photo"
    tools:layout="@layout/fragment_display_photo" >
    <argument android:name="bitmap"
              app:argType="android.graphics.Bitmap"/>
</fragment>

So when I wanna to move from CreateRoomFragment to DisplayPhotoFragment,I use the do as below:

NavDirections action = CreateRoomFragmentDirections.actionCreateRoomFragmentToDisplayPhotoFragment(selectedPhoto);
Navigation.findNavController(view).navigate(action);

Doing this,I can navigate to DisplayPhotoFragment.

But when I press back button of the device and also the Back arrow from the toolbar,it cant go back to CreateRoomFragment.

I tried this,but still unable to back to previous fragment:

requireActivity().getOnBackPressedDispatcher().addCallback(getViewLifecycleOwner(),
                new OnBackPressedCallback(true) {
                    @Override
                    public void handleOnBackPressed() {

                       navController.navigateUp();  //I tried this 
                       navController.popBackStack(R.id.createRoomFragment,false); //and also this
                    }
                });

Main Problem now:

By using the code above,the screen didnt go back to previous Fragment(CreateRoomFragment).It still stuck in DisplayPhotoFragment,but at the same time,an API method in CreateRoomFragment onViewCreated section is being called.

What causing this? and how can I solve this problem?

Answer 1

I had the same problem. For me the issue was that I was using a LiveData boolean to decide when to go to the next fragment. When I then navigated back/up the boolean was still true so it would automatically navigate forward again.