yusufarisoy / compose-paging

Paging library for Jetpack Compose

ComposePaging

ComposePaging library for Jetpack Compose.

About

ComposePaging is a paging library for Compose. ComposePaging makes it possible to use dynamic Composables as skippable for better performance like it should be.

Metrics

Metrics is the way of measuring the performance of composables. Ideally a composable method should be restartable and skipabble for the compiler to work with best performance.

Besides being lazy, ComposePaging Feed items are easy to maintain and it's easy to make them restartable and skipabble while being updatable for better performance for your Android application.

Attributes

Attribute	Description
prefetchDistance	Defines the item distance to request the next page before reaching the bottom
initialPage	Defines the initial page for the first request

Demo

Composables items in the pages are updated without having any performance issues.

ComposePager	ComposePagerWithQuery
home_screen.mp4	search_screen.mp4

Usage

PagingSource

ComposePagingSource is used for requesting pages. Example for more info.

class PagingSource(
    private val useCase: UseCase,
    private val onPageLoaded: (itemCount: Int) -> Unit
) : ComposePagingSource<UiModel>() {

    override suspend fun load(params: Params): Result<UiModel> {
        val page = params.page
        val response = useCase.run(UseCase.Params(page = page))

        if (page == 0 && response.items.isEmpty()) {
            return Result.Error(NetworkError.EmptyFeedError("No results found"))
        }

        onPageLoaded(response.count)

        return Result.Page(data = response.items, hasNextPage = response.hasNextPage)
    }
}

PagingData and Pager in ViewModel

ComposePagingData is used for storing the page data, it stores SnapshotStateList for better performance and maintainability. Look for more info.

ComposePager is used for managing the page data and states. Look for more info.

val feed: ComposePagingData<UiModel> = ComposePagingData(prefetchDistance = 2)
private val pager: ComposePager<UiModel> = ComposePager(
    pagingSource = PagingSource(
        useCase = useCase,
        onPageLoaded = ::onPageLoaded
    ),
    initialPage = 1
)

Setup

allprojects {
    repositories {
        ...
        maven { url 'https://jitpack.io' }
    }
}

dependencies {
        implementation 'com.github.yusufarisoy:compose-paging:1.0.0'
}