The workaround I did was to store the list in a variable and

Question

The workaround I did was to store the list in a variable and then set it in `onCreateView` but it s very elegant I think

rkeazor · Answer

Store your data in a View Model and use Android s new Navigation Component grimacing

anstaendig · Answer

How would that solve the problem

rkeazor · Answer

If you create a list in the viewmodel and than pass it to your recyclerview there should way your list is destroyed just because you leave the fragment And the NavComponent makes it easy to handle the backstack

anstaendig · Answer

But we are trying to solve a problem with view bindings

anstaendig · Answer

One has nothing to do with the other

anstaendig · Answer

Oh

rkeazor · Answer

oh sorry i was answering your first question

anstaendig · Answer

I m mixing up two things here I think

anstaendig · Answer

smile

rkeazor · Answer

lol

anstaendig · Answer

I was talking about < Paul Woitaschek> s problem mixed it up sorry

Nelson Almendra · Answer

yeah I think viewmodel can t fix this it s a view binding problem

rkeazor · Answer

Where do you create the list of data that is displayed in your recyclerview

Nelson Almendra · Answer

I have a livedata object in viewmodel and I subscribe to the observe callback

rkeazor · Answer

hmm than it should be fine Unless your recreating the the livedata object or viewmodel each time you return from the fragment

anstaendig · Answer

How do you navigate from fragment to fragment

Nelson Almendra · Answer

`supportFragmentManager beginTransaction replace R id root layout detailsFragment gistDetails addToBackStack gistsList commit `

Nelson Almendra · Answer

sorry no code identation

anstaendig · Answer

And you get the viewModel based on the fragments context I guess

anstaendig · Answer

That way the ViewModel is being recreated most probably as replacing the fragment causes it to be destroyed

anstaendig · Answer

Try to get the ViewModel by passing the activity to ViewModelProviders of instead of the fragment and see if that helps

Nelson Almendra · Answer

oh just noticed someting the viewmodel is being created with the activity context

Nelson Almendra · Answer

that might be the problem

anstaendig · Answer

That should actually make it live

Nelson Almendra · Answer

yes I get it the activity is never destroyed in this process

anstaendig · Answer

Where do you observe the LiveData

anstaendig · Answer

and fetch the ViewModel

Nelson Almendra · Answer

in onCreate of the main activity

anstaendig · Answer

Wait so the fragment does not have it s own ViewModel

Nelson Almendra · Answer

should it have

anstaendig · Answer

Well that s a different question slightly smiling face

Nelson Almendra · Answer

initially I did t use fragments I changed to fragments later

anstaendig · Answer

So where do you observe inside the fragment

Nelson Almendra · Answer

I don t i pass the list that I receive to the fragment

anstaendig · Answer

Observe it in the fragment instead

Nelson Almendra · Answer

ok that makes sense actually

Nelson Almendra · Answer

thank you

anstaendig · Answer

Otherwise when clicking back you have to manually give that list to the fragment again

anstaendig · Answer

If the Activity then does not do anything itself with that data I would argue that the fragment should have it s own ViewModel for that

Nelson Almendra · Answer

exactly that what was happening

Nelson Almendra · Answer

sure it makes much more sense

Nelson Almendra · Answer

just one thing where shoudl the viewmodel be created in the fragment onAttach

anstaendig · Answer

I usually do it in onActivityCreated IIRC

anstaendig · Answer

But onAttach should work give it a try

Nelson Almendra · Answer

onAttach works but when I press back the recyclerview is empty again

anstaendig · Answer

try onActivityCreated then

anstaendig · Answer

Looking at your activities fragments and viewmodels code would help also if that doesn t do the trick

Nelson Almendra · Answer

onActivityCreated worked

anstaendig · Answer

+1 skin tone 2

Nelson Almendra · Answer

thank you so much

Nelson Almendra · Answer

the onActivityCreated is called again and the viewmodel fetchs the data again

Nelson Almendra · Answer

damn I could never realise that the fragment should have it s own viewmodel instead of the activity

anstaendig · Answer

It should not refetch the data as the same instance of the ViewModel should be returned

anstaendig · Answer

I would need some more of that code though

Nelson Almendra · Answer

no it s not refetching the data again is just using the same instance

anstaendig · Answer

So then it works fine

Nelson Almendra · Answer

yeah

anstaendig · Answer

Good

Nelson Almendra · Answer

I ve moved the viewModel initialization to on Attach and leave the observe to LiveData object in onActivityCreated

Nelson Almendra · Answer

that makes sense right if it was in onActivityCreated it would create a new instance

anstaendig · Answer

No it doesn t The provider of the ViewModel takes care of returning the same ViewModel

anstaendig · Answer

Shouldn t matter where you call it

Nelson Almendra · Answer

ok it s basically a singleton under the hood

Sam · Answer

For best place to observe viewmodel in a Fragment refere to <https medium com BladeCoder architecture components pitfalls part 1 9300dd969808>

Sam · Answer

register your observers using the special lifecycle returned by getViewLifecycleOwner in onCreateView

anstaendig · Answer

That was fixed in androidx 1 0 0 and suplib 28 0 0

Sam · Answer

Yeah and thats why it is recommended to use getViewLifeCycleOwner

Sam · Answer

Get a LifecycleOwner that represents the Fragment s View lifecycle In most cases this mirrors the lifecycle of the Fragment itself but in cases of detached Fragments the lifecycle of the Fragment can be considerably longer than the lifecycle of the View itself <https developer android com reference androidx fragment app Fragment getviewlifecycleowner>

Sam · Answer

Either ways it is not a big deal just to not worry about being notified for a detached fragment