FacetListConnector(
searcher: SingleIndexSearcher,
filterState: FilterState,
attribute: Attribute,
selectionMode: SelectionMode,
facets: [Facet],
operator: RefinementOperator,
groupName: String,
controller: FacetListController,
presenter: FacetListPresenter
)
RefinementList is a filtering view that displays facets
and lets users refine the search results by filtering on specific values.
Requirements
The attribute provided to the widget must be in attributes for faceting,
either on the dashboard or using the attributesForFaceting parameter with the API.
Examples
Instantiate a FacetListConnector and launch an initial search on its searcher.
let searcher = HitsSearcher(appID: "YourApplicationID",
apiKey: "YourSearchOnlyAPIKey",
indexName: "YourIndexName")
let filterState: FilterState = .init()
let categoryTableViewController: UITableViewController = .init()
let categoryListController: FacetListTableController = .init(tableView: categoryTableViewController.tableView)
let facetListPresenter: FacetListPresenter = .init(sortBy: [.count(order: .descending)], limit: 5, showEmptyFacets: false)
let categoryConnector: FacetListConnector = .init(searcher: searcher,
filterState: filterState,
attribute: "category",
selectionMode: .multiple,
facets: [.init(value: "initial facet", count: 10)],
operator: .and,
controller: categoryListController,
presenter: facetListPresenter)
searcher.search()
Parameters
The Searcher that handles your searches. selectionMode
SelectionMode
default: .multiple
Whether a user can select .single or .multiple values.
If specified, the default facet value(s) to apply.
operator
RefinementOperator
required
Whether you apply an and or or behavior to the facets in the filterState.For example, if you select color as the attribute and an or behavior,
the filter sent to Algolia will be color:red OR color:green.Use filters or facet filters for more complex result refinement. groupName
String
default: The raw value of the `attribute` parameter
Filter group name.
controller
FacetListController
default: nil
Controller interfacing with a concrete facet list view.
presenter
SelectableListPresentable
default: nil
Presenter defining how a facet appears in the controller.
Presenter
sortBy
[FacetSortCriterion]
default:"[.count(order: .descending)]"
How to sort facets. Must be one or more of the following values:
.count(order: .descending).count(order: .ascending).alphabetical(order: .descending).alphabetical(order: .ascending).isRefined
// Tie-breaking algorithm where refined values are shown first.
// If refined values are tied, show the facets with the largest counts.
// If counts are tied, show facets in alphabetical order.
facetListPresenter =
FacetListPresenter(
sortBy: [.isRefined, .count(order: .descending), .alphabetical(order: .ascending)]
)
The number of facet values to retrieve.facetListPresenter = .init(limit: 5)
Whether to show facets with a facet count of 0.facetListPresenter = .init(showEmptyFacets: false)
facetListPresenter = .init(showEmptyFacets: true)
Low-level API
If you want to fully control the RefinementList components and connect them manually, you can use the following components:
Searcher. The Searcher that handles your searches.FilterState. The current state of the filters.FacetListInteractor. The logic applied to the facets.FacetListController. The controller that interfaces with a concrete facet list view.FacetListPresenter. Optional. The presenter that controls the sorting and other settings of the facet list view.
let searcher = HitsSearcher(appID: "YourApplicationID",
apiKey: "YourSearchOnlyAPIKey",
indexName: "YourIndexName")
let filterState: FilterState = .init()
let facetListInteractor: FacetListInteractor = .init(facets: [.init(value: "initial facet", count: 10)], selectionMode: .multiple)
let categoryTableViewController: UITableViewController = .init()
let categoryListController: FacetListTableController = .init(tableView: categoryTableViewController.tableView)
let facetListPresenter: FacetListPresenter = .init(sortBy: [.count(order: .descending)], limit: 5, showEmptyFacets: false)
facetListInteractor.connectSearcher(searcher, with: "category")
facetListInteractor.connectFilterState(filterState, with: "category", operator: .or)
facetListInteractor.connectController(categoryListController)
facetListInteractor.connectController(categoryListController, with: facetListPresenter)
searcher.connectFilterState(filterState)
searcher.search()
Customizing your view
The controllers provided by default,
like the FacetListTableViewController work well when you want to use native UIKit with their default behavior.
If you want to use another component such as a UICollectionView,
a third-party input view, or you want to introduce some custom behavior to the already provided UIKit component,
you can create your own controller conforming to the FacetListController protocol.
Protocol
var onClick: ((Facet) -> Void)?:
Closure to call when a new facet is clicked.
func setSelectableItems(selectableItems: [SelectableItem<Facet>])
Function called when a new array of selectable facets is updated. This is the UI State of the refinement list.
func reload()
Function called when you want ti reload the list view.
Implementation example
open class FacetListTableViewController: NSObject, FacetListController {
public var onClick: ((Facet) -> Void)?
public var tableView: UITableView
var selectableItems: [SelectableItem<Facet>] = []
var cellID: String
public init(tableView: UITableView, cellID: String = "FacetList") {
self.tableView = tableView
self.cellID = cellID
super.init()
tableView.register(UITableViewCell.self, forCellReuseIdentifier: cellID)
tableView.dataSource = self
tableView.delegate = self
}
public func setSelectableItems(selectableItems: [SelectableItem<Facet>]) {
self.selectableItems = selectableItems
}
public func reload() {
tableView.reloadData()
}
}
extension FacetListTableViewController: UITableViewDataSource {
open func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return selectableItems.count
}
open func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: cellID, for: indexPath)
let selectableRefinement: SelectableItem<Facet> = selectableItems[indexPath.row]
let facetAttributedString = NSMutableAttributedString(string: selectableRefinement.item.value)
let facetCountStringColor = [NSAttributedString.Key.foregroundColor: UIColor.gray, .font: UIFont.systemFont(ofSize: 14)]
let facetCountString = NSAttributedString(string: " (\(selectableRefinement.item.count))", attributes: facetCountStringColor)
facetAttributedString.append(facetCountString)
cell.textLabel?.attributedText = facetAttributedString
cell.accessoryType = selectableRefinement.isSelected ? .checkmark : .none
return cell
}
}
extension FacetListTableViewController: UITableViewDelegate {
open func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let selectableItem = selectableItems[indexPath.row]
self.onClick?(selectableItem.item)
}
}
SwiftUI
InstantSearch provides the FacetList SwiftUI view which you can embed in your views.
It uses FacetListObservableController as a data model,
which is an implementation of the FacetListController protocol adapted for usage with SwiftUI.
FacetListObservableController must be connected to the FacetListConnector or FacetListInteractor,
like any other FacetListController implementation.
You can define the appearance of the view representing a single facet and its selection state
or use the FacetRow view provided by InstantSearch.
struct ContentView: View {
@ObservedObject var facetListController: FacetListObservableController
var body: some View {
FacetList(facetListController) { facet, isSelected in
// Use the implementation provided by InstantSearch
// FacetRow(facet: facet,
isSelected: isSelected)
// Or declare a custom single facet view
HStack {
Text(facet.value)
Spacer()
if isSelected {
Image(systemName: "checkmark")
.foregroundColor(.accentColor)
}
}
.contentShape(Rectangle())
.frame(idealHeight: 44)
.padding(.horizontal, 5)
}
}
}
FacetListObservableController as a data model.
It provides facets and selections properties along with convenient toggle and isSelected functions to streamline the design process of your custom SwiftUI view.
