API Reference / InstantSearch Android / Infinite Hits (Paging)

Infinite Hits (Paging)

About this widget

Infinite Hits is a view with helpers that displays a paginated list of search results.
It leverages Android Architecture Components’ Paging library and LiveData to provide lifecycle-aware, observable search results that can be loaded as the user scrolls.

To add Infinite Hits to your search experience, use these components:

  • Searcher: The Searcher that handles your searches.
  • SearcherSingleIndexDataSource: The PageKeyedDataSource that will load hits incrementally.
  • LivePagedListBuilder: The builder creating LiveData, based on the given DataSource and Config.
  • T: A data class representing a search result.
  • FilterState: In order for the paginated list to refresh when filters change.
See code examples

Examples

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class MyActivity : AppCompatActivity() {

    val client = ClientSearch(
        ApplicationID("YourApplicationID"),
        APIKey("YourAPIKey")
    )
    val index = client.initIndex(IndexName("YourIndexName"))
    val searcher = SearcherSingleIndex(index)
    val dataSourceFactory = SearcherSingleIndexDataSource.Factory(searcher) { it.deserialize(Movie.serializer()) }
    val pagedListConfig = PagedList.Config.Builder()
        .setPageSize(10) // configure according to your needs
        .build()
    val movies = LivePagedListBuilder<Int, Movie>(dataSourceFactory, pagedListConfig).build()
    val filterState = FilterState()
    val adapter = MovieAdapter()
    val connection = ConnectionHandler()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        connection += filterState.connectPagedList(movies)

        movies.observe(this, Observer { hits -> adapter.submitList(hits) })

        searcher.searchAsync()
    }

    override fun onDestroy() {
        super.onDestroy()
        searcher.cancel()
        connection.disconnect()
    }
}

@Serializable
data class Movie(
    val title: String
)

class MovieViewHolder(val view: TextView) : RecyclerView.ViewHolder(view) {

    fun bind(data: Movie) {
        view.text = data.title
    }
}

class MovieAdapter : PagedListAdapter<Movie, MovieViewHolder>(MovieAdapter) {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MovieViewHolder {
        return MovieViewHolder(TextView(parent.context))
    }

    override fun onBindViewHolder(holder: MovieViewHolder, position: Int) {
        val movie = getItem(position)

        if (movie != null) holder.bind(movie)
    }

    companion object : DiffUtil.ItemCallback<Movie>() {

        override fun areItemsTheSame(
            oldItem: Movie,
            newItem: Movie
        ): Boolean {
            return oldItem == newItem
        }

        override fun areContentsTheSame(
            oldItem: Movie,
            newItem: Movie
        ): Boolean {
            return oldItem.title == newItem.title
        }
    }
}

Compose UI

InstantSearch provides the Paginator, which exposes a flow property for paging data, and an invalidate() method to stop loading. You need to connect Paginator to other components, such as SearchBoxConnector, FilterState, or FacetListConnector.

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class MyActivity : AppCompatActivity() {
    val client = ClientSearch(
        ApplicationID("YourApplicationID"),
        APIKey("YourAPIKey")
    )
    val index = client.initIndex(IndexName("YourIndexName"))
    val searcher = SearcherSingleIndex(index)
    val pagingConfig = PagingConfig(pageSize = 10)
    val hitsPaginator = Paginator(searcher, pagingConfig) { it.deserialize(Movie.serializer()) }
    val searchBoxState = SearchBoxState()
    val searchBox = SearchBoxConnector(searcher)
    val connections = ConnectionHandler()

    init {
        connections += searchBox.connectView(searchBoxState)
        connections += searchBox.connectPaginator(hitsPaginator)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            SearchBox(
                searchBoxState = searchBoxState
            )
            val hitsPaging = hitsPaginator.flow.collectAsLazyPagingItems()
            LazyColumn {
                items(hitsPaging) { movie ->
                    movie?.let { Text(it.title) }
                }
            }
        }
        searcher.searchAsync()
    }

    override fun onDestroy() {
        super.onDestroy()
        connections.disconnect()
        searcher.cancel()
    }
}

Parameters

observer
type: Observer<in PagedList<T>>
Required

A function called on new hits. You should forward the hits the UI to display them.
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val observer = Observer<PagedList<Movie>> { hits -> adapter.submitList(hits) }
movies.observe(this, observer)
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InstantSearch Android v2