How to calculate empty space in lazy column after last visible item

Question

How to calculate empty space in lazy column after last visible item in Jetpack compose.

Answer 1

You can use Modifier.onSizeChanged{intSize->} on your LazyColumn and its parent Composble and check the distance between them.

One thing to note here is it requires another recomposition after getting size of parent and list. So you might need do to a check or refer this answer to get dimensions without recomposition

How to get exact size without recomposition?

@Composable
private fun LazyColumnParentSizeSample() {

    var parentHeight by remember { mutableStateOf(0) }
    var listHeight by remember { mutableStateOf(0) }
    Column(modifier=Modifier.fillMaxSize()
        .onSizeChanged {
            parentHeight = it.height
        }) {

        LazyColumn(modifier=Modifier.onSizeChanged {
            listHeight = it.height
        }){
            items(10) {
                Text("Item: $it")
            }
        }
        Text("listHeight: $listHeight, parent height: $parentHeight, difference: ${parentHeight-listHeight}")

    }
}

To get value in dp you can use LocalDensity.current

    val diffInDp = LocalDensity.current.run {(parentHeight-listHeight).toDp()  }