compose lazy staggered grid

compose lazy staggered grid.md

콤포즈 lazy staggered grid

@Composable
fun LazyStaggeredGrid(
    columnCount: Int,
    contentPadding: PaddingValues = PaddingValues(0.dp),
    content: @Composable LazyStaggeredGridScope.() -> Unit,
) {
    val states: Array<LazyListState> = (0 until columnCount)
        .map { rememberLazyListState() }
        .toTypedArray()
    val scope = rememberCoroutineScope { Dispatchers.Main.immediate }
    val scroll = rememberScrollableState { delta ->
        scope.launch { states.forEach {  it.scrollBy(-delta) }}
        delta
    }
    val gridScope = LazyStaggeredGridScope(columnCount)
    content(gridScope)

    Box(modifier = Modifier
        .scrollable(scroll, Orientation.Vertical, flingBehavior = ScrollableDefaults.flingBehavior())
    ) {
        Row {
            for (index in 0 until columnCount) {
                LazyColumn(
                    userScrollEnabled = false,
                    contentPadding = contentPadding,
                    state = states[index],
                    modifier = Modifier.weight(1f)
                ) {
                    for ((key, itemContent) in gridScope.items[index]) {
                        item(key = key) {
                            itemContent()
                        }
                    }
                }
            }
        }
    }
}

class LazyStaggeredGridScope(
    private val columnCount: Int,
) {

    var currentIndex = 0
    val items: Array<MutableList<Pair<Any?, @Composable () -> Unit>>> = Array(columnCount) { mutableListOf() }

    fun item(key: Any? = null, content: @Composable () -> Unit) {
        items[currentIndex % columnCount] += key to content
        currentIndex += 1
    }
}

참조: https://github.com/savvasdalkitsis/lazy-staggered-grid