Is it ok to have different ViewModels for each Composable on a single screen in Android?

Question

In a previous StackOverflow question it was recommended that each Activity should have a single ViewModel. If there are different 'sections' on the screen which require different model data, then this should be handled with multiple LiveData in single ViewModel. https://stackoverflow.com/a/54482736/15597975

With Compose now released, is it ok to have different ViewModels for different 'sections' on the screen i.e. each section is represented as a different composable and each composable has it's own ViewModel with own odel LiveData?

Answer 1

We recommend having 1 ViewModel per Screen and then passing down the state from there. This makes Composables more reusable and testable because your Composables aren't tied to a particular ViewModel, just the state they require.

@Composable
fun MyScreen(viewModel: ViewModel) {
   Column {
      TopPart(viewModel.topState)
      BottomPart(viewModel.bottomState)
   }
}

@Composable
fun TopPart(topState: TopState) {}

@Composable
fun BottomPart(bottomState: BottomState) {}