hi! what is the right way to use ViewModel with Compose Desktop? I've tried several times, but I alw...

# compose-desktop

[Alejandro Serrano.Mena]

hi! what is the right way to use ViewModel with Compose Desktop? I've tried several times, but I always get

No ViewModelStoreOwner was provided via LocalViewModelStoreOwner

for context, I've added androidx.lifecycle:lifecycle-viewmodel-compose:2.8.3 as dependency, and also org.jetbrains.kotlinx:kotlinx-coroutines-swing:1.8.1

[Pablichjenkov]

I think the right artifact is: "org.jetbrains.androidx.lifecycle:lifecycle-viewmodel-compose",
You may want to include the navigation library too, ViewModel on its own doesn't do much

[Marcin Wisniowski]

I am using this artifact, but I am still getting No ViewModelStoreOwner was provided via LocalViewModelStoreOwner. I've read the docs here: https://www.jetbrains.com/help/kotlin-multiplatform-dev/compose-viewmodel.html
But I don't see anything I'm missing.

[Pablichjenkov]

I think you have to import the navigation artifact, check here: https://github.com/MatkovIvan/nav_cupcake/blob/master/gradle%2Flibs.versions.toml#L8
But not sure if this one is needed too:
lifecycle-runtime-compose = module = "org.jetbrains.androidx.lifecycle:lifecycle-runtime-compose"

[Marcin Wisniowski]

It looks to be impossible: https://issuetracker.google.com/issues/336842920#comment2

You have to use Compose UI 1.7.0-alpha05, but the latest version on desktop is alpha02.

[Pablichjenkov]

Oh I see, interesting. It seems we will have to wait for a bit. In the meantime versions in the project linked above work for desktop. There is an issue in Android tho 🤷‍♂️, similar to the one you linked.

[Ivan Matkov]

> You have to use Compose UI 1.7.0-alpha05, but the latest version on desktop is alpha02.
We're aligning only first two numbers in version (like 1.7) with Google. Compose Multiplatform 1.7.0-alpha02 is based on Google's 1.7.0-beta05. It's mentioned in release notes.

But to make it work you don't need any alphas - combination with Compose 1.6.11 + Lifecycle 2.8.0 should work.

If you're facing with 336842920 on Android - update (2.8.4) lifecycle on Android only. Just add Google's dependency to you androidMain source set. It works because JB library redirects to Google's binary on Android

> similar to the one you linked
Mentioned issue is not related to initial topic (view model is missed, not lifecycle). It should be provided by Compose UI since 1.6.10. So my only guess is - you're using older version of Compose.

[Marcin Wisniowski]

@Ivan Matkov It does not seem to be working for me. I am using:
Compose 1.7.0-alpha2
org.jetbrains.androidx.lifecycle:lifecycle-viewmodel-compose:2.8.0
org.jetbrains.androidx.lifecycle:lifecycle-runtime-compose:2.8.0
org.jetbrains.androidx.navigation:navigation-compose:2.8.0-alpha08
And getting java.lang.IllegalStateException: CompositionLocal LocalLifecycleOwner not present, just like in the issue I linked.

[Ivan Matkov]

Android?

[Marcin Wisniowski]

Desktop only

[Ivan Matkov]

What Compose version do you use?

[Marcin Wisniowski]

1.7.0-alpha02

[Ivan Matkov]

ah, sorry, I see

[Ivan Matkov]

Please share the minimal reproduction project, I'll check

[Ivan Matkov]

It should be provided - https://github.com/JetBrains/compose-multiplatform-core/blob/release/1.7.0-alpha02[…]in/kotlin/androidx/compose/ui/scene/ComposeContainer.desktop.kt

[Ivan Matkov]

There are 2 "LocalLifecycleOwner"
• androidx.compose.ui.platform.LocalLifecycleOwner
• androidx.lifecycle.compose.LocalLifecycleOwner
Which one do you use?

[Marcin Wisniowski]

I see that file you linked provides import androidx.lifecycle.compose.LocalLifecycleOwner, my understanding is that the org.jetbrains.androidx.lifecycle:lifecycle-* packages expect androidx.compose.ui.platform.LocalLifecycleOwner, which is the source of the error.

[Ivan Matkov]

No. "compose.ui.platform" is the old place, it's moved to lifecycle library in 1.7 with deprecation + redirection

[Ivan Matkov]

https://github.com/JetBrains/compose-multiplatform-core/pull/1449/files

[Ivan Matkov]

https://r.android.com/2989145

[Ivan Matkov]

Anyway. Both should work in 1.7. I'd like to look at reproduction project to understand your case

[Marcin Wisniowski]

Then I'm not sure where is the incompatibility. I will try creating a minimal reproduction project later today.

[Marcin Wisniowski]

I got it working, turns out the NavHost composable has to be inside of a Window.

[Ivan Matkov]

Right. We're providing the lifecycle of the window. I know that we have composable context outside, but since it's hard to match the multiwindow lifecycle to the state and I don't know the actual use case why it's needed, we didn't provide it for "application".

[Ivan Matkov]

Do you want to use different windows in the same nav graph?

[Ivan Matkov]

If so could you please file a feature request with use case explanation

[Marcin Wisniowski]

No, in fact I didn't want to use navigation at all, but added it as a test to see if it fixes the problem. I only wanted to use ViewModel. I have now removed the NavHost and can see the ViewModel still works fine now that it's retrieved inside of a Window.

[Marcin Wisniowski]

I do have one application-level ViewModel though, and I guess I won't be able to migrate it to KMM ViewModel in that case.

[Ivan Matkov]

You can provide your custom VM owner in any place

[Ivan Matkov]

private class ComposeViewModelStoreOwner: ViewModelStoreOwner {
    override val viewModelStore: ViewModelStore = ViewModelStore()
    fun dispose() { viewModelStore.clear() }
}

/**
 * Return remembered [ViewModelStoreOwner] with the scope of current composable.
 */
@Composable
private fun rememberViewModelStoreOwner(): ViewModelStoreOwner {
    val viewModelStoreOwner = remember { ComposeViewModelStoreOwner() }
    DisposableEffect(viewModelStoreOwner) {
        onDispose { viewModelStoreOwner.dispose() }
    }
    return viewModelStoreOwner
}

And set it via

CompositionLocalProvider(LocalViewModelStoreOwner provides owner)

[Ivan Matkov]

Or if you need it application wide, just use global object without any "remember" stuff

[Ivan Matkov]

Please note that ComposeViewModelStoreOwner above should be more complicated for Android case - it needs to be backed up by system one to deal with their recreation stuff

Or just use it as fallback like

LocalViewModelStoreOwner.current ?: rememberViewModelStoreOwner()

[Marcin Wisniowski]

Thanks, I will try these 👍

[Marcin Wisniowski]

@Ivan Matkov Turns out I actually have a bunch of usages where I need the ViewModel outside of a Window, because the UI state I am collecting from the ViewModel is used to control the window (for example the window position). So I have 1 VM per Window, but I need the UI state to configure the window, and so need the VM before the Window is created.

The way the Lifecycle/VM works seems suitable to apps where there is a single window, a NavHost inside, and different screens with VM's.
In my application I have lots of smaller widgets each in separate windows, each "screen" is it's own Window, and one VM per Window.

[Ivan Matkov]

Please file an feature request with description of your use case then. For the current version you can provide owners (like simple global ones) manually

[Marcin Wisniowski]

https://youtrack.jetbrains.com/issue/CMP-5911/Common-ViewModel-cannot-be-used-to-control-a-Window