How to update Jetpack compose UI by override method or outside the function-CodePudding

I am converting my older XML UI as per requirement. in there, I am unable to update by Jetpack compose UI by my override function. In some research I see many websites shows remember function helps for state update, but, as for my situation. I need to update my UI by the override function that I implemented in another class.

    private lateinit var materialList: List<Material>


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        if (savedInstanceState == null)
            viewModel.initFilters(initText, initFilters)
        materialpresenter.attachView(this, lifecycle)

        materialList= listOf()
        setContent {
            FilterBox(materialList)
        }

    }


@Composable
fun FilterBox(materialList: List<Material>) {
    var selectedIndex by remember { mutableStateOf("0") }
    val onItemClick = { index: Int -> selectedIndex = "0" }

    FlowRow(
        modifier = Modifier.padding(top = 14.dp),
        mainAxisAlignment = MainAxisAlignment.Start,
        crossAxisSpacing = 8.dp,
        mainAxisSpacing = 4.dp
    ) {
        materialList.forEach { hashTag ->
            if (selectedIndex == hashTag.id) {
                FilterSelectionItemText(
                    hashTag.slug, index = 0,
                    onClick = onItemClick
                )
            } else {
                FilterUnSelectionItemText(
                    hashTag.slug, index = 0,
                    onClick = onItemClick
                )
            }

        }
    }
}

    override fun onMaterials(list: List<Material>) {
        print("list :-"   list)
        materialList = list
    }

I want to update my FilterBox Composable UI by my onMaterials function. because when I am print this this its printing data properly, but my UI is not updating.

CodePudding user response：

To update composable UI you first need state which holds data because composable functions are updating when there is a some state/data changes

in this example your data is materialList: List<Material>

You need to wrap your data with state / mutable state / mutable state list (for lists)

Change your list to stateList or mutableState...

private val materialList: MutableState<List<Material>> = mutableStateOf(emptyList())

Collect your data from state in setContent composable like:

val myList: List<Material> by materialList // here you will get updated last data as List<Material>

FilterBox(myList)

Update state from overridden method.

  override fun onMaterials(list: List<Material>){
        materialList.value = list // your updated List
    }