Filter Numeric Range

Signature

NumberRangeConnector<Number>(
  filterState: FilterState,
  attribute: Attribute,
  bounds: ClosedRange<Number>?,
  range: ClosedRange<Number>,
  operator: RefinementOperator,
  groupName: String?,
  controller: NumberRangeController
)

See code examples

About this widget

Filter Numeric Range is a filtering component made to filter between two numeric values. The most common interface for this is a slider.

Examples

Instantiate a NumberRangeConnector and launch an initial search on its searcher.

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let searcher = HitsSearcher(appID: "YourApplicationID",
                            apiKey: "YourApiKey",
                            indexName: "YourIndexName")
let filterState: FilterState = .init()

let numberRangeController: RangeSliderController = .init(rangeSlider: .init())

let numericRangeConnector: NumberRangeConnector<Double> = .init(searcher: searcher,
                                                                filterState: filterState,
                                                                attribute: "price",
                                                                controller: numberRangeController)

searcher.search()

Parameters

`searcher`	type: HitsSearcher Required The `Searcher` that handles your searches.
`filterState`	type: FilterState Required The `FilterState` that holds your filters.
`attribute`	type: Attribute Required The attribute to filter.
`interactor`	type: NumberRangeInteractor<Number> default: .init() Required The logic applied to the numeric range.
`bounds`	type: ClosedRange<Number>? default: nil Optional The Bounds limiting the max and the min value of the range.
`range`	type: ClosedRange<Number> default: nil Optional The initial range value.
`operator`	type: RefinementOperator default: .and Optional Whether the filter is added to a conjuncitve(`and`) or a disjuncitve (`or`) group in the filter state.
`groupName`	type: String default: The value of the `attribute` parameter Optional Filter group name in the `FilterState`
`controller`	type: NumberRangeController default: nil Optional The Controller interfacing with a concrete number range view.

Low-level API

If you want to fully control the Filter Numeric Range 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.
NumberRangeInteractor: The logic applied to the numeric ranges.
NumberRangeController: The controller that interfaces with a concrete numeric range view.

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let searcher = HitsSearcher(appID: "YourApplicationID",
                            apiKey: "YourApiKey",
                            indexName: "YourIndexName")
let filterState: FilterState = .init()

let numericRangeInteractor: NumberRangeInteractor<Double> = .init()
let numberRangeController: RangeSliderController = .init(rangeSlider: .init())

let priceAttribute: Attribute = "price"
  
searcher.connectFilterState(filterState)

numericRangeInteractor.connectFilterState(filterState, attribute: priceAttribute)
numericRangeInteractor.connectSearcher(searcher, attribute: priceAttribute)
numericRangeInteractor.connectController(numberRangeController)

searcher.search()

Customizing your view

If you want to use 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 NumberRangeController protocol.

Protocol

func setBounds(_ bounds: ClosedRange<Double>):

Function called when the minimum and maximum of numeric filter view have been defined.

var onRangeChanged: ((ClosedRange<Double>) -> Void)?

Closure to call when new bounds is set for the numeric range filter.

Example

Let’s assume you have a range slider control providing the following API:

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class RangeSlider: UIControl {
  var lowerValue: Double
  var upperValue: Double
  var minimumValue: Double
  var maximumValue: Double
}

Then, you could implement the NumberRangeController including this control as follows:

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class RangeSliderController: NumberRangeController {
  
  let rangeSlider: RangeSlider

  var onRangeChanged: ((ClosedRange<Double>) -> Void)?
  
  func setBounds(_ bounds: ClosedRange<Double>) {
    rangeSlider.minimumValue = bounds.lowerBound
    rangeSlider.maximumValue = bounds.upperBound
    setItem(bounds)
  }
  
  func setItem(_ item: ClosedRange<Double>) {
    rangeSlider.lowerValue = item.lowerBound
    rangeSlider.upperValue = item.upperBound
  }
  
  init(rangeSlider: RangeSlider) {
    self.rangeSlider = rangeSlider
    rangeSlider.addTarget(self, action: #selector(onValueChanged(sender:)), for: [.touchUpInside, .touchUpOutside])
  }
  
  @objc func onValueChanged(sender: RangeSlider) {
    onRangeChanged?(sender.lowerValue...sender.upperValue)
  }
  
}

SwiftUI

InstantSearch provides the NumberRangeObservableController data model, which is an implementation of the NumberRangeController protocol adapted for usage with SwiftUI. NumberRangeObservableController must be connected to the NumberRangeConnector or NumberRangeConnector like any other NumberRangeController implementation.

The example of the number range view using two Stepper components provided by SwiftUI.

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struct ContentView: View {
  
  @ObservedObject var numberRangeController: NumberRangeObservableController<Int>
  
  var body: some View {
    let range = numberRangeController.range
    VStack{
      Stepper(onIncrement: {
        if let range = makeRange(range.lowerBound+1, range.upperBound) {
          numberRangeController.range = range
        }
      },
      onDecrement: {
        if let range = makeRange(range.lowerBound-1, range.upperBound) {
          numberRangeController.range = range
        }
      },
      label: {
        Text("Lower bound: \(range.lowerBound)")
      })
      Stepper(onIncrement: {
        if let range = makeRange(range.lowerBound, range.upperBound+1) {
          numberRangeController.range = range
        }
      },
      onDecrement: {
        if let range = makeRange(range.lowerBound, range.upperBound-1) {
          numberRangeController.range = range
        }
      },
      label: {
        Text("Upper bound: \(numberRangeController.range.upperBound)")
      })
    }
  }
  
  func makeRange(_ lowerBound: Int, _ upperBound: Int) -> ClosedRange<Int>? {
    if lowerBound < upperBound &&
       numberRangeController.bounds.contains(lowerBound) &&
       numberRangeController.bounds.contains(upperBound) {
      return lowerBound...upperBound
    } else {
      return nil
    }
  }
  
}

If you prefer to create a custom SwiftUI view that presents the numeric range, you can directly use the NumberRangeObservableController as a data model. It provides range and bounds properties to streamline the design process of your custom SwiftUI view.

Check out the example to see this widget in action.

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