Hey :wave: Is there any way to scope a `viewModel` to a navigation graph using Jetpack compose navig...

# koin

[Nacho Ruiz Martin]

Hey 👋
Is there any way to scope a viewModel to a navigation graph using Jetpack compose navigation?
I would like a viewModel to be used by several composables and get cleared and reinstantiated when the user exists -> reenters to that screen flow.

[Nacho Ruiz Martin]

If I just use it like in the docs:

@Composable
fun App(viewModel : Clazz = getViewModel()) {
    ...
}

@Composable
fun App2(viewModel : Clazz = getViewModel()) {
    ...
}

I’m getting different instances of the viewmodel on each composable.
I guess this is expected, but is there any way to share it?

[Nacho Ruiz Martin]

So basically I’m asking if this:
https://developer.android.com/jetpack/compose/libraries#hilt

val parentViewModel = hiltViewModel<ParentViewModel>(
    navController.getBackStackEntry("Parent")
)

is possible with Koin.

[Nacho Ruiz Martin]

What I don't really get is why I'm receiving different instances of the ViewModel on the composables if they are used within the same Activity.
I had to retrieve the ViewModel on the Activity and not on the Composables to be able to share data between them. Is this the expected behaviour?

[Slava Glushenkov]

https://github.com/InsertKoinIO/koin/issues/1079

[Nacho Ruiz Martin]

Is downgrading a solution for this?

[Slava Glushenkov]

Seems no. I saw external fix before. This is a problem with viewModelOwner detection. But can't find it again now.

[Nacho Ruiz Martin]

“This parameter allows wiring your ViewModel with a custom ViewModelOwner, like Graph Navigation component:” https://link.medium.com/7RzafKeMqib

[Nacho Ruiz Martin]

Maybe?

[Nacho Ruiz Martin]

@arnaud.giuliani sorry for the ping. Are you aware of this issue with the compose navigation component? Do you have any idea how to fix it? I could prepare a PR with some directions.

[arnaud.giuliani]

Yes, scoping VM is not yet really safe 😕 we need work on that

[Nacho Ruiz Martin]

Ok, please, let me know if there’s something I can do to help.

[arnaud.giuliani]

VM, Navigation & Scopes are not quite clear for now. I would need a sandbox app to help work against it for Koin.

[Nacho Ruiz Martin]

I can set that up

[arnaud.giuliani]

Yes, if you can. I always use a “toy app”, really minimal to just illustrate the usecases we need to get working

[arnaud.giuliani]

if you want to help, you can draft something 👍

[Nacho Ruiz Martin]

I will start by creating the toy app, I’m not really sure in which direction should the actual fix go, though.

[Nacho Ruiz Martin]

https://github.com/iruizmar/koin-nav-compose-toy/tree/master
Here it is. It's very basic! I wrote down a description on the Readme.
Please, let me know if you are looking for something else.

[arnaud.giuliani]

Great, let’s continue a thread on #koin-dev 👍