Hey guys, I have a question about `setContent{}`. I have a shared viewModel between a Fragment and ...

# compose

[Ky]

Hey guys, I have a question about setContent{}. I have a shared viewModel between a Fragment and an Activity. In the activity xml I have a ComposeView and in onStart I’m attempting to update that ComposeView like this

Code block 1

Inside the composable view is something like

Code block 2

The problem is that setContent in the activity is only being called when the activity is attached/detached. It is not observing the data stream but if it switch the code to this(still in onStart):

Code block 3

This works fine. Is there something I’m missing about setContent{} in the Activity?

[kevindmoore]

I thought you were supposed to call setContent in onCreate not onStart

[Ky]

@kevindmoore no matter, same result

[Ky]

viewFromXml.setContent {
    Theme {
        ComposableView(
            viewModel = viewModel
        ) { someVal ->
            doSomeStuff(someVal)
        }
    }
}

ComposableView(
  viewModel: ViewModel){ 
  val state = viewModel.subscribeAsState
...
...

viewModel.subscribe({ state ->
            viewFromXml.apply {
                setContent {
                    Theme {
                        Composableview(
                            state = state
                        ) { someVal ->
                            doSomeStuff(someVal)
                    }
                }
            }
        }
}

[kevindmoore]

Hmm. I've never seen it done this way. Can you have a field in the model that you can use Compose rememberState calls with? I think you are mixing old with new

[Ky]

I’m working with legacy code so unfortunately some things need to remain xml. I think it’s pretty common to pass a viewmodel into the composable function and observe it’s state to trigger recomposition.
https://developer.android.com/jetpack/compose/libraries

I have this <ComposeView> at the activity level and the changes in this SharedViewModel state are coming from a Fragment. The Fragment which shares this ViewModel, observes the state changes just fine.

If I trigger the Activity lifecycle changes, onStop and then back to onStart. Then setContent{} called again and the ComposableView(viewmodel) then observes the latest state and updates.