In my OpinionViewModel:

val labels = MutableStateFlow<MutableList<String>>(mutableListOf())

when actions come from UI (from BottomSheet item) I add item to my list:

 state.labels.value.add("Lorem Ipsu") 

My main @Composable:

fun OpinionScreen(viewModel: OpinionViewModel) {
        
            val scrollState = rememberScrollState()
            val bottomState = rememberModalBottomSheetState(ModalBottomSheetValue.Hidden)
        
            val items by viewModel.state.labels.collectAsState()
            
            AppTheme(isSystemInDarkTheme()) {
                ModalBottomSheetLayout(
                    sheetState = bottomState,
                    sheetContent = { AddPhotoBottomSheet()}) {
                    Scaffold(
                        topBar = { TopBar()},
                        content = {
                            Box(
                                modifier = Modifier.fillMaxSize()
                            ) {
                                Column(
                                    modifier = Modifier
                                        .fillMaxWidth()
                                        .wrapContentHeight()
                                        .verticalScroll(scrollState)
                                ) {
                                    FirstSection()
                                    HowLongUsageSection(photos)
                                    ThirdSection()
                                }
                            }
        
                        })
                }
            }
        }

@Composable Section:

fun HowLongUsageSection(labels: MutableList<String>) {
    Column(
        modifier = Modifier
            .fillMaxWidth()
            .padding(top = 10.dp, start = 10.dp, end = 10.dp),
        horizontalAlignment = Alignment.CenterHorizontally
    ) {
        labels.forEach {
            Text(text = it, color = Color.Blue)
        }
}

The problem is the no recomposition happening. I need to go back and open UI again to see added item. Am I missing something or the problem is related to bottom sheet?

CodePudding user response：

The problem is that your MutableList does not change when you modify its contents (the reference still remains the same). To fix this, use a List instead of MutableList.

val labels = MutableStateFlow(listOf<String>())

To add an element to it:

label.value  = "Lorem Ipsum"

Now the state flow will emit a new value and your UI will get updated.