LazyColumn inside Column with verticalScroll modifier throws exception-CodePudding

In one of my composables, a Lazycolumn is nested inside a Column composable. I want to be able to scroll the entire Column along with the Lazycolumn. But, specifying the verticalScroll modifier property on Column results in the following exception causing the app to crash. How can I fix this?

Exception

java.lang.IllegalStateException: Vertically scrollable component was measured with an infinity maximum height constraints, which is disallowed. One of the common reasons is nesting layouts like LazyColumn and Column(Modifier.verticalScroll()).

Composable

Column(
    modifier = Modifier
        .fillMaxWidth()
        .verticalScroll(rememberScrollState())
        .padding(bottom = 100.dp),
    verticalArrangement = Arrangement.Center,
    horizontalAlignment = Alignment.CenterHorizontally
) {
    LazyColumn(
        modifier = Modifier
            .fillMaxWidth()
    ) {
        items(
            items = allItems!!,
            key = { item ->
                item.id
            }
        ) { item ->
            ShoppingListScreenItem(
                navController = navController,
                item = item,
                sharedViewModel = sharedViewModel
            ) { isChecked ->
                scope.launch {
                    shoppingListScreenViewModel.changeItemChecked(item!!, isChecked)
                }
            }
        }
    }

   ...

Button(
    modifier = Modifier.padding(vertical = 24.dp),
    onClick = {
        navController.navigate(NavScreens.AddItemScreen.route) {
            popUpTo(NavScreens.AddItemScreen.route) {
                inclusive = true
            }
        }
    }
) {
    Text("Go to add item screen")
  }
}

CodePudding user response：

This happens when you wish to measure your LazyColumn with Constraints with Constraints.Infinity for the maxHeight which is not permitted as described in error log. There should be a fixed height or you shouldn't have another Scrollable with same orientation.

Column(
    modifier = Modifier
         // This is the cause
        .verticalScroll(rememberScrollState())
) {
    LazyColumn(
       // and not having a Modifier that could return non-infinite max height contraint
        modifier = Modifier
            .fillMaxWidth()
    ) {

}

If you don't know exact height you can assign Modifier.weight(1f) to LazyColumn.

Contraints

This section is extra about `Constraints` and measurement you can skip this part if you are not interested in how it works

What i mean by measuring with with Constraints.Infinity is

when you create a Layout in Compose you use

Layout(modifier=modifier, content=content){measurables, constraints->
}

then you get child Composables as measurables and each one as

measurable.measure(constraints)

These constraints change based on your size modifier. When there is a scroll and you don't use any Size modifier Constraints return minHeight =0, maxHeight= some big number i don't recall.

Modifier.fillMaxWidth()

Modifier.fillMaxWidth().weight(1f)

Easiest way to check Constraints with different Modifiers or with scroll is getting it from BoxWithConstraints