Coroutines integration

The screenModelScope and StateScreenModelare part of the core library.

CoroutineScope

The ScreenModel provides a screenModelScope property. It's canceled automatically when the ScreenModel is disposed.

class PostDetailsScreenModel(
    private val repository: PostRepository
) : ScreenModel {

    fun getPost(id: String) {
        screenModelScope.launch {
            val post = repository.getPost(id)
            // ...
        }
    }
}

State-aware ScreenModel

If your ScreenModel needs to provide a state, use the StateScreenModel. Set the initial state on the constructor and use mutableState to change the current state.

class PostDetailsScreenModel(
    private val repository: PostRepository
) : StateScreenModel<PostDetailsScreenModel.State>(State.Init) {

    sealed class State {
        object Init : State()
        object Loading : State()
        data class Result(val post: Post) : State()
    }

    fun getPost(id: String) {
        coroutineScope.launch {
            mutableState.value = State.Loading
            mutableState.value = State.Result(post = repository.getPost(id))
        }
    }
}

In your screen use state.collectAsState() and handle the current state.

class PostDetailsScreen : Screen {

    @Composable
    override fun Content() {
        val screenModel = rememberScreenModel<PostDetailsScreenModel>()
        val state by screenModel.state.collectAsState()

        when (state) {
            is State.Loading -> LoadingContent()
            is State.Result -> PostContent(state.post)
        }
    }
}

Sample

Sample code here.

Desktop Note

If you are targeting Desktop, you should provide the dependency org.jetbrains.kotlinx:kotlinx-coroutines-swing, the screenModelScope depends on Dispatchers.Main provided by this library on Desktop. We don't include it because this library is incompatible with IntelliJ Plugin, see. If you are targeting Desktop for IntelliJ plugins, this library does not require to be provied.