SettingScreen.kt

@Composable
fun SettingScreen(
    settingScreenState: SettingScreenState = rememberSettingScreenState()
) {
    SettingScreen(
        scaffoldState = settingScreenState.scaffoldState,
        isDarkModeSetting = settingScreenState.isDarkMode,
        onDarkModeSettingChanged = {
            settingScreenState.onDarkModeChange(it)
        }
    )
}

@Composable
fun SettingScreen(
    isDarkModeSetting: Boolean,
    onDarkModeSettingChanged: (Boolean) -> Unit,
    scaffoldState: ScaffoldState
) {
    Scaffold(scaffoldState = scaffoldState) {
        MySwitch(checked = isDarkModeSetting, onCheckChanged = {
            onDarkModeSettingChanged(it)
        })
    }
}

// SettingScreenState is the state holder.
// SettingScreenState is now just a class that does not inherit anything.
// This is to preserve the state of Compose so that it is not bound to any other lifecycle.
class SettingScreenState(
    // You can have other Compose States.
    val scaffoldState: ScaffoldState,
    // If you want to access business logic or screen state, 
    // the State holder can also depend on the ViewModel.
    // This is not a problem because ViewModel has a longer lifetime.
    private val settingViewModel: SettingViewModel,
    private val coroutinesScope: CoroutineScope,
) {
    // Variables, etc. can be made composable if necessary.
    val isDarkMode: Boolean
        @Composable get() = settingViewModel.isDarkMode.collectAsState().value

    fun onDarkModeChange(isDarkMode: Boolean) {
        settingViewModel.onDarkModeChange(isDarkMode)
        coroutinesScope.launch {
            scaffoldState.snackbarHostState.showSnackbar("Dark mode changed!", )
        }
    }
}

@Composable
fun rememberSettingScreenState(
    scaffoldState: ScaffoldState = rememberScaffoldState(),
    coroutinesScope: CoroutineScope = rememberCoroutineScope(),
    settingViewModel: SettingViewModel = viewModel(),
) = remember {
    SettingScreenState(
        coroutinesScope = coroutinesScope,
        scaffoldState = scaffoldState,
        settingViewModel = settingViewModel
    )
}