android - 如何在 Android Jetpack Compose 中结合使用 LazyColumn stickyHeader 和 Paging？

Question

我已经实现了LazyColumn与 Paging ，但我现在尝试添加 sticky headers也是。
stickyHeader() items() 中的功能不可用范围，所以我不明白这应该如何工作。

@Composable
fun MovieList(movies: Flow<PagingData<Movie>>) {
    val lazyMovieItems: LazyPagingItems<Movie> = movies.collectAsLazyPagingItems()

    LazyColumn {
        // TODO: Add sticky headers
        items(lazyMovieItems) { movie ->
            MovieItem(movie = movie!!)
        }
    }
}

如何添加 stickyHeader年代？

Answer 1

@Composable
fun MovieList(movies: Flow<PagingData<Movie>>) {
    val lazyMovieItems = movies.collectAsLazyPagingItems()

    LazyColumn {
        val itemCount = lazyMovieItems.itemCount
        var lastCharacter: Char? = null

        for (index in 0 until itemCount) {
            // Gets item without notifying Paging of the item access,
            // which would otherwise trigger page loads
            val movie = lazyMovieItems.peek(index)
            val character = movie?.name?.first()

            if (movie !== null && character != lastCharacter) {
                stickyHeader(key = character) {
                    MovieHeader(character)
                }
            }

            item(key = movie?.id) {
                // Gets item, triggering page loads if needed
                val movieItem = lazyMovieItems[index]

                Movie(movieItem)
            }

            lastCharacter = character
        }
    }
}