Filter List

Signature

FilterListConnector.All(
    filters: List<Filter>,
    filterState: FilterState,
    selectionMode: SelectionMode,
    groupID: FilterGroupID
)

See code examples

See demo

About this widget

FilterList is a filtering view that displays any kind of filters, and lets the user refine the search results by selecting them.

Compared to the RefinementList, which takes its values from the search response facets, this widget displays filters that you add yourself.

Examples

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class MyActivity: AppCompatActivity() {
  val searcher = HitsSearcher(
      applicationID = ApplicationID("YourApplicationID"),
      apiKey = APIKey("YourSearchOnlyAPIKey"),
      indexName = IndexName("YourIndexName")
  )
    val filterState = FilterState()
    val color = Attribute("color")
    val price = Attribute("price")
    val filters = listOf(
        Filter.Numeric(price, 5..10),
        Filter.Tag("coupon"),
        Filter.Facet(color, "red"),
        Filter.Facet(color, "black"),
        Filter.Numeric(price, NumericOperator.Greater, 100)
    )
    val groupAll = groupAnd(all)
    val filterListConnector = FilterListConnector.All(
        filters = filters, 
        filterState = filterState, 
        groupID = groupAll
    )
    val connection = ConnectionHandler(filterListConnector, searcher.connectFilterState(filterState))

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val filterListView: FilterListView.All = MyFilterListAdapter() // your `FilterListView.All` implementation
        connection += filterListConnector.connectView(filterListView)
        searcher.searchAsync()
    }

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

Low-level API

If you want to fully control the FilterList components and connect them manually, use the following components:

Searcher: The Searcher that handles your searches.
FilterState: The current state of the filters.
FilterListViewModel.All: The logic applied to the filters.
FilterListView.All: The view that renders the filters.
FilterPresenter: Optional. The presenter to customize the display of the filters.

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class MyActivity : AppCompatActivity() {
    val searcher = HitsSearcher(
        applicationID = ApplicationID("YourApplicationID"),
        apiKey = APIKey("YourSearchOnlyAPIKey"),
        indexName = IndexName("YourIndexName")
    )
    val filterState = FilterState()
    val color = Attribute("color")
    val price = Attribute("price")
    val filters = listOf(
        Filter.Numeric(price, 5..10),
        Filter.Tag("coupon"),
        Filter.Facet(color, "red"),
        Filter.Facet(color, "black"),
        Filter.Numeric(price, NumericOperator.Greater, 100)
    )
    val viewModel = FilterListViewModel.All(filters)
    val connection = ConnectionHandler()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val view: FilterListView.All =  MyFilterListAdapter() // your `FilterListView.All` implementation
        connection += searcher.connectFilterState(filterState)
        connection += viewModel.connectFilterState(filterState)
        connection += viewModel.connectView(view)

        searcher.searchAsync()
    }

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

Compose UI

InstantSearch provides the FilterListState as a state model, which is an implementation of the FilterListView interface. You need to connect FilterListState to the FilterListConnector or FilterListViewModel like any other FilterListView implementation.

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class MyActivity: AppCompatActivity() {
    val searcher = HitsSearcher(
        applicationID = ApplicationID("YourApplicationID"),
        apiKey = APIKey("YourSearchOnlyAPIKey"),
        indexName = IndexName("YourIndexName")
    )
    val filterState = FilterState()
    val color = Attribute("color")
    val price = Attribute("price")
    val filters = listOf(
        Filter.Numeric(price, 5..10),
        Filter.Tag("coupon"),
        Filter.Facet(color, "red"),
        Filter.Facet(color, "black"),
        Filter.Numeric(price, NumericOperator.Greater, 100)
    )
    val groupAll = groupAnd(all)
    val filterListState = FilterListState<Filter>()
    val filterList = FilterListConnector.All(
        filters = filters,
        filterState = filterState,
        groupID = groupAll
    )
    val connections = ConnectionHandler(filterList)

    init {
        connections += searcher.connectFilterState(filterState)
        connections += filterList.connectView(filterListState)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            filterListState.items.forEach { selectableFacet ->
                FilterRow( // your own UI composable to display `SelectableItem<Filter>`
                    selectableFilter = selectableFacet,
                    onClick = { filterListState.onSelection?.invoke(it) }
                )
            }
        }
        searcher.searchAsync()
    }

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

Parameters

Parameter	Description
`filters`	type: List<Filter> Required The filters to display.
`filterState`	type: FilterState Required The `FilterState` that will hold your filters.
`selectionMode`	type: SelectionMode default: Multiple Optional Whether the list can have `Single` or `Multiple` selections.
`groupID`	type: FilterGroupID default: FilterGroupID(FilterOperator.And) Optional The identifier for the group of filters.

View

Parameter Description


            view

type: FilterListView.All

Optional

The view that renders the filters.

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val view: FilterListView.All = MyFilterListAdapter()
filterListConnector.connectView(view)

// Example of FilterListView.All implementation
class MyFilterListAdapter : FilterListView.All,
    ListAdapter<SelectableItem<Filter>, FilterListViewHolder>(DiffUtilItem()) {

    override var onSelection: Callback<Filter>? = null

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): FilterListViewHolder {
        return FilterListViewHolder(parent.inflate(R.layout.list_item_selectable))
    }

    override fun onBindViewHolder(holder: FilterListViewHolder, position: Int) {
        val (filter, selected) = getItem(position)
        holder.bind(FilterPresenterImpl()(filter), selected) { onSelection?.invoke(filter) }
    }

    override fun setItems(items: List<SelectableItem<Filter>>) {
        submitList(items)
    }
}

class DiffUtilItem<T : Filter> : DiffUtil.ItemCallback<SelectableItem<T>>() {
    override fun areItemsTheSame(oldItem: SelectableItem<T>, newItem: SelectableItem<T>): Boolean {
        return oldItem.first == newItem.first
    }

    override fun areContentsTheSame(oldItem: SelectableItem<T>, newItem: SelectableItem<T>): Boolean {
        return oldItem == newItem
    }
}

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