그룹 Jetpack Compose의 LazyColumn 및 Paging3

완성 화면

gradle

def paging_version = "3.0.1"
implementation "androidx.paging:paging-runtime-ktx:$paging_version"
implementation "androidx.paging:paging-compose:1.0.0-alpha14"

PagingSource

package sobaya.app.repository.paging

import androidx.paging.PagingSource
import androidx.paging.PagingState

class SamplePagingSource : PagingSource<Int, String>() {
    override fun getRefreshKey(state: PagingState<Int, String>): Int? {
        return state.anchorPosition
    }

    override suspend fun load(params: LoadParams<Int>): LoadResult<Int, String> {
        val perPage = params.loadSize
        val page = params.key ?: 1
        val next = page + 1
        val prev = if (page == 1) null else page - 1

        return LoadResult.Page(
            data = (0..perPage).map { "$page-$it-DATA" },
            prevKey = prev,
            nextKey = next
        )
    }
}

ViewModel

val samplePagingFlow: Flow<PagingData<String>> = Pager(
    PagingConfig(pageSize = 10, initialLoadSize = 10)
) {
    SamplePagingSource()
}.flow.cachedIn(viewModelScope)

Composable

@Composable
fun SamplePagingList(
    viewModel: UserListViewModel
) {
    val lazyPagingItems = viewModel.samplePagingFlow.collectAsLazyPagingItems()

    LazyColumn {
        items(lazyPagingItems) { sample ->
            Text(text = sample ?: "")
        }
    }
}

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