State restoration

// Multiplatform ViewModel

class MainViewModel(scope: CoroutineScope, store: StateFlowStore) :
    BaseReactiveState<ErrorEvents>(scope) {

    val count: StateFlow<Int> = store.getData("count", 0)
}

// Android ViewModel

class MainViewModel(store: StateFlowStore) : ViewModel() {
    val count: StateFlow<Int> = store.getData("count", 0)
}

A StateFlowStore provides a similar API to Android’s SavedStateHandle, but based on StateFlow instead of LiveData.

With InMemoryStateFlowStore you can do e.g. unit testing or abstract away platform differences in multiplatform projects.

This is how you can create an Android ViewModel with a StateFlowStore:

// Multiplatform ViewModel

class MainFragment : Fragment() {
    private val viewModel by reactiveState { MainViewModel(scope, stateFlowStore) }

    // ...
}

// Android ViewModel

class MainFragment : Fragment() {
    private val viewModel by stateFlowViewModel { MainViewModel(stateFlowStore) }

    // ...
}

Both by reactiveState and by stateFlowViewModel provide a stateFlowStore value within their lambda blocks.