In one of my composable components, I want to create a ViewModel and use it as the state source. However, once this composable is destroyed, viewModel should also get destroyed and next time the composable is rendered, a fresh new viewModel should be created. I achieved "creating a new viewModel" by introducing a remembered, random key as follows:

// using itemId as key would still give me the same viewModel when this composable gets recreated
val key = remember(itemId) { UUID.randomUUID().toString() }
val commentsViewModel = viewModel<CommentsViewModel>(key = key)

However, I cannot remove this particular viewModel from the store without removing other viewModels that were stored in the same place. How should I proceed with this? Is this an anti-pattern?

This is a known issue. See the feature request https://issuetracker.google.com/issues/165642391

Maybe you mix something up here. But when you use remember {} also without any key the created value is lost when the composable is disposed. You can track the lifecycle of a composable with.

onActive { log("onActive") ; onDispose { log("dispose") } }

Best advice – wait for the bug Ian linked to land. If you wanted to build something today, my recommendation would be to make an object that implements

CompositionLifecycleObserver

that's responsible for the cleanup code. https://cs.android.com/androidx/platform/frameworks/support/+/androidx-master-dev:compose/runtime/runtime/src/commonMain/kotlin/androidx/compose/runtime/CompositionLifecycleObserver.kt;l=37?q=CompositionLifecycle

Maybe just create an instance of your ViewModel without using this special viewModel<...>() system

Any object that implements that will call

onEnter

and

onLeave

when it's remembered (or forgotten) by composition

Maybe also viewModel is not what you want. Just use a normal class

You'd need to use

viewModel

if you want to have state that is retained over configuration changes (

remember

and the like do not do that)

You could just use

rememberSavedInstanceState

Both

viewModel

and

rememberSavedInstanceState

would work with the upcoming Navigation framework integration

As this is just an experiment, it's best to wait for the fix to land