How to know from what fragment I'm returning when using Navigation Component?

Asked Oct 08 '19 at 12:23

Active Oct 08 '19 at 12:23

Viewed 124 times

I have four fragments already set up in my app using Navigation Components:

I can go from MainFragment to MoviesFragment or TrailersFragment as well as from the UserFragment to one of them.

From the MainFragment I can simply navigate to the MoviesFragment fragment using this code:

ActionMainFragmentToMoviesFragment action = actionMainFragmentToMoviesFragment();
action.setFromMainFragment(true);
Navigation.findNavController(rootView).navigate(action);

To navigate to the TrailersFragment fragment, I'm using similar code. When I use:

.setFromMainFragment(true);

In MoviesFragment for instance, I can simply get a boolean from the Bundle so I can know from which fragment I'm coming from, either from MainFragmnet or UserFragment and it workd very well.

And here comes the problem. When I want to get from MoviesFragment back to MainFragment, I don't navigate as above, I just press the back button. So the problem is that I don't know in the MainFragment from which fragment I'm returning (MoviesFragment or TrailersFragment).

What should I do to know from which fragment I'm coming from in MainFragment?

asked Oct 08 '19 at 12:23

Jorn

Send an event through a shared ViewModel scoped to the shared NavGraph – EpicPandaForce Oct 08 '19 at 12:26
@EpicPandaForce Thanks again for trying to help me but I have no clue on how can I do this :( Can you please provide me an answer for that? – Jorn Oct 08 '19 at 12:47
@EpicPandaForce Is that solution using a ViewModel working also in Java or only in Kotlin? – Jorn Oct 08 '19 at 14:42
As coroutines are not involved when using ViewModel, it works both in Java and Kotlin. – EpicPandaForce Oct 08 '19 at 14:46
@EpicPandaForce I'll give it a try and get you back. – Jorn Oct 08 '19 at 14:47
1

@EpicPandaForce Did it with a shared ViewModel. Thank you! – Jorn Oct 09 '19 at 07:51
@EpicPandaForce If you want, you can add an answer. Was a little tricky but it solved my problem. – Jorn Oct 09 '19 at 13:03

How to know from what fragment I'm returning when using Navigation Component?

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