Find place

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Sample viewer app

Find places of interest near a location or within a specific area.

Search function Search results

Use case

When getting directions or looking for nearby places, users may only know what the place has ("food"), the type of place ("gym"), or the generic place name ("Starbucks"), rather than the specific address. You can get suggestions and locations for these places of interest (POIs) using a natural language query. Additionally, you can filter the results to a specific area.

How to use the sample

Choose a type of place in the first field and an area to search within in the second field. Tap the Search button to show the results of the query on the map. Tap on a result pin to show its name and address. If you pan away from the result area, a "Redo search in this area" button will appear. Tap it to query again for the currently viewed area on the map.

How it works

  1. Create an AGSLocatorTask using a URL to a locator service.
  2. Find the location for an address (or city name) to search within:

    • Create AGSGeocodeParameters.
    • Add return fields to the parameters' AGSGeocodeParameters.resultAttributeNames collection. Only add a single "*" option to return all fields.
    • Call AGSLocatorTask.geocode(withSearchText:parameters:completion:) to get a list of AGSGeocodeResults.
    • Use AGSGeocodeResult.displayLocation from one of the results to search within.
  3. Get place of interest (POI) suggestions based on a place name query:

    • Create AGSSuggestParameters.
    • Add "POI" to the parameters' categories collection.
    • Call AGSLocatorTask.suggest(withSearchText:parameters:completion) to get a list of AGSSuggestResult.
    • The AGSSuggestResult will have a label to display in the search suggestions list.
  4. Use one of the suggestions or a user-written query to find the locations of POIs:

    • Create AGSGeocodeParameters.
    • Set the parameters' searchArea to AGSGeometry of the area you want to search.
    • Call AGSLocatorTask.geocode(withSearchText:parameters:completion:) to get a list of AGSGeocodeResults.
    • Display the places of interest using the results' AGSGeocodeResult.displayLocations.

Relevant API

  • AGSGeocodeParameters
  • AGSGeocodeResult
  • AGSLocatorTask
  • AGSSuggestParameters
  • AGSSuggestResult

About the data

This sample uses the World Geocoding Service.

Tags

businesses, geocode, locations, locator, places of interest, POI, point of interest, search, suggestions

Sample Code

FindPlaceViewController.swift
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
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// Copyright 2016 Esri.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import UIKit
import ArcGIS

class FindPlaceViewController: UIViewController {
    @IBOutlet var mapView: AGSMapView!
    @IBOutlet var tableView: UITableView!
    @IBOutlet var preferredSearchLocationTextField: UITextField!
    @IBOutlet var poiTextField: UITextField!
    @IBOutlet var tableViewHeightConstraint: NSLayoutConstraint!
    @IBOutlet var extentSearchButton: UIButton!
    @IBOutlet var overlayView: UIView!

    private var textFieldLocationButton: UIButton!

    private var map: AGSMap!
    private let graphicsOverlay = AGSGraphicsOverlay()

    private var locatorTask: AGSLocatorTask!
    private var suggestResults = [AGSSuggestResult]() {
        didSet {
            tableView.reloadData()
        }
    }
    private var suggestRequestOperation: AGSCancelable!
    private var selectedSuggestResult: AGSSuggestResult!
    private var preferredSearchLocation: AGSPoint!
    private var selectedTextField: UITextField!

    private var isTableViewVisible = true
    private var isTableViewAnimating = false
    private var canDoExtentSearch = false {
        didSet {
            if !canDoExtentSearch {
                self.extentSearchButton.isHidden = true
            }
        }
    }

    private var currentLocationText = "Current Location"
    private var isUsingCurrentLocation = false
    private let tableViewHeight: CGFloat = 120

    override func viewDidLoad() {
        super.viewDidLoad()

        // add the source code button item to the right of navigation bar
        (self.navigationItem.rightBarButtonItem as! SourceCodeBarButtonItem).filenames = ["FindPlaceViewController"]

        // create an instance of a map with ESRI topographic basemap
        self.map = AGSMap(basemapStyle: .arcGISTopographic)

        // assign the map to the map view
        self.mapView.map = self.map
        self.mapView.touchDelegate = self

        // start location display
        self.mapView.locationDisplay.autoPanMode = .recenter
        self.mapView.locationDisplay.start { [weak self] (error: Error?) in
            if error == nil {
                // if the location display starts, update the preferred search location
                // textfield's text
                self?.preferredSearchLocationTextField.text = self!.currentLocationText
            }
        }

        // logic to show the extent search button
        self.mapView.viewpointChangedHandler = { [weak self] in
            DispatchQueue.main.async {
                if self?.canDoExtentSearch ?? false {
                    self?.extentSearchButton.isHidden = false
                }
            }
        }

        // add the graphicsOverlay to the map view
        self.mapView.graphicsOverlays.add(graphicsOverlay)

        // initialize locator task
        self.locatorTask = AGSLocatorTask(url: URL(string: "https://geocode.arcgis.com/arcgis/rest/services/World/GeocodeServer")!)

        // hide suggest result table view by default
        self.animateTableView(expand: false)

        // hide the overlay view by default
        self.overlayView.isHidden = true

        // register for keyboard notification in order to toggle overlay view on and off
        NotificationCenter.default.addObserver(self, selector: #selector(FindPlaceViewController.showOverlayView), name: UIResponder.keyboardWillShowNotification, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(FindPlaceViewController.hideOverlayView), name: UIResponder.keyboardWillHideNotification, object: nil)

        // add the left view images for both the textfields
        self.setupTextFieldLeftViews()
    }

    // method to show search icon and pin icon for the textfields
    private func setupTextFieldLeftViews() {
        var leftView = self.textFieldViewWithImage("SearchIcon")
        self.poiTextField.leftView = leftView
        self.poiTextField.leftViewMode = .always

        leftView = self.textFieldViewWithImage("PinIcon")
        self.preferredSearchLocationTextField.leftView = leftView
        self.preferredSearchLocationTextField.leftViewMode = .always
    }

    // method returns a UIView with an imageView as the subview
    // with an image instantiated using the name provided
    private func textFieldViewWithImage(_ imageName: String) -> UIView {
        let view = UIView(frame: CGRect(x: 0, y: 0, width: 25, height: 30))
        let imageView = UIImageView(image: UIImage(named: imageName))
        imageView.frame = CGRect(x: 5, y: 5, width: 20, height: 20)
        view.addSubview(imageView)
        return view
    }

    // method to toggle the suggestions table view on and off
    private func animateTableView(expand: Bool) {
        if (expand != self.isTableViewVisible) && !self.isTableViewAnimating {
            self.isTableViewAnimating = true
            self.tableViewHeightConstraint.constant = expand ? self.tableViewHeight : 0
            UIView.animate(
                withDuration: 0.1,
                animations: { [weak self] in
                    self?.view.layoutIfNeeded()
                },
                completion: { [weak self] (_) in
                    self?.isTableViewAnimating = false
                    self?.isTableViewVisible = expand
                }
            )
        }
    }

    // method to clear prefered location information
    // hide the suggestions table view, empty previously selected
    // suggest result and previously fetch search location
    private func clearPreferredLocationInfo() {
        self.animateTableView(expand: false)
        self.selectedSuggestResult = nil
        self.preferredSearchLocation = nil
    }

    // method to show callout for a graphic
    private func showCalloutForGraphic(_ graphic: AGSGraphic, tapLocation: AGSPoint) {
        let addressType = graphic.attributes["Addr_type"] as! String
        self.mapView.callout.title = graphic.attributes["Match_addr"] as? String ?? ""

        if addressType == "POI" {
            self.mapView.callout.detail = graphic.attributes["Place_addr"] as? String ?? ""
        } else {
            self.mapView.callout.detail = nil
        }
        self.mapView.callout.isAccessoryButtonHidden = true
        self.mapView.callout.show(for: graphic, tapLocation: tapLocation, animated: true)
    }

    // method returns a graphic object for the specified point and attributes
    private func graphicForPoint(_ point: AGSPoint, attributes: [String: AnyObject]?) -> AGSGraphic {
        let markerImage = UIImage(named: "RedMarker")!
        let symbol = AGSPictureMarkerSymbol(image: markerImage)
        symbol.leaderOffsetY = markerImage.size.height / 2
        symbol.offsetY = markerImage.size.height / 2
        let graphic = AGSGraphic(geometry: point, symbol: symbol, attributes: attributes)
        return graphic
    }

    // method to zoom to an array of graphics
    func zoomToGraphics(_ graphics: [AGSGraphic]) {
        if let spatialReference = graphics.first?.geometry?.spatialReference {
            let multipoint = AGSMultipointBuilder(spatialReference: spatialReference)
            for graphic in graphics {
                multipoint.points.add(graphic.geometry as! AGSPoint)
            }
            self.mapView.setViewpoint(AGSViewpoint(targetExtent: multipoint.extent)) { [weak self] (_) in
                self?.canDoExtentSearch = true
            }
        }
    }

    // MARK: - Suggestions logic

    enum SuggestionType {
        case poi
        case populatedPlace
    }

    private func fetchSuggestions(_ string: String, suggestionType: SuggestionType, textField: UITextField) {
        // cancel previous requests
        if self.suggestRequestOperation != nil {
            self.suggestRequestOperation.cancel()
        }

        // initialize suggest parameters
        let suggestParameters = AGSSuggestParameters()
        let flag: Bool = (suggestionType == SuggestionType.poi)
        suggestParameters.categories = flag ? ["POI"] : ["Populated Place"]
        suggestParameters.preferredSearchLocation = flag ? nil : self.mapView.locationDisplay.mapLocation

        // get suggestions
        self.suggestRequestOperation = self.locatorTask.suggest(withSearchText: string, parameters: suggestParameters) { [weak self] (suggestResults, error) in
            // check if the search string has not changed in the meanwhile
            guard string == textField.text else { return }

            if let error = error {
                print(error.localizedDescription)
            } else if let suggestResults = suggestResults {
                // update the suggest results and reload the table
                self?.suggestResults = suggestResults
            }
        }
    }

    private func geocodeUsingSuggestResult(_ suggestResult: AGSSuggestResult, completion: @escaping () -> Void) {
        // create geocode params
        let params = AGSGeocodeParameters()
        params.outputSpatialReference = self.mapView.spatialReference

        // geocode with selected suggest result
        self.locatorTask.geocode(with: suggestResult, parameters: params) { [weak self] (result: [AGSGeocodeResult]?, error: Error?) in
            if let error = error {
                print(error.localizedDescription)
            } else if let geoCodeResults = result?.first {
                self?.preferredSearchLocation = geoCodeResults.displayLocation
                completion()
            } else {
                print("No location found for the suggest result")
            }
        }
    }

    private func geocodePOIs(_ poi: String, location: AGSPoint?, extent: AGSGeometry?) {
        // hide callout if already visible
        self.mapView.callout.dismiss()

        // hide extent search button
        self.canDoExtentSearch = false
        self.extentSearchButton.isHidden = true

        // remove all previous graphics
        self.graphicsOverlay.graphics.removeAllObjects()

        // parameters for geocoding POIs
        let params = AGSGeocodeParameters()
        params.preferredSearchLocation = location
        params.searchArea = extent
        params.outputSpatialReference = self.mapView.spatialReference
        params.resultAttributeNames.append(contentsOf: ["*"])

        // geocode using the search text and params
        self.locatorTask.geocode(withSearchText: poi, parameters: params) { [weak self] (results: [AGSGeocodeResult]?, error: Error?) in
            if let error = error {
                print(error.localizedDescription)
                self?.canDoExtentSearch = true
            } else {
                self?.handleGeocodeResultsForPOIs(results, areExtentBased: (extent != nil))
            }
        }
    }

    func handleGeocodeResultsForPOIs(_ geocodeResults: [AGSGeocodeResult]?, areExtentBased: Bool) {
        if let results = geocodeResults,
            !results.isEmpty {
            // show the graphics on the map
            for result in results {
                let graphic = self.graphicForPoint(result.displayLocation!, attributes: result.attributes as [String: AnyObject]?)

                self.graphicsOverlay.graphics.add(graphic)
            }

            // extent search button display logic
            // if search was not based on extent, then zoom to the graphics. On completion
            // set the canDoExtentSearch flag to true
            // else if search is based on extent, no need to zoom, simply set the flag to true
            if !areExtentBased {
                self.zoomToGraphics(self.graphicsOverlay.graphics as AnyObject as! [AGSGraphic])
            } else {
                self.canDoExtentSearch = true
            }
        } else {
            // show alert for no results
            print("No results found")
            // set canDoExtentSearch flag to true, so that if the user pans, the button becomes visible
            self.canDoExtentSearch = true
        }
    }

    // MARK: - Actions

    private func search() {
        // validation
        guard let poi = self.poiTextField.text, !poi.isEmpty else {
            print("Point of interest required")
            return
        }

        // cancel previous requests
        if self.suggestRequestOperation != nil {
            self.suggestRequestOperation.cancel()
        }

        // hide the table view
        self.animateTableView(expand: false)

        // check if a suggestion is present
        if self.selectedSuggestResult != nil {
            // since a suggestion is selected, check if it was already geocoded to a location
            // if no, then goecode the suggestion
            // else use the geocoded location, to find the POIs
            if self.preferredSearchLocation == nil {
                self.geocodeUsingSuggestResult(self.selectedSuggestResult) { [weak self] in
                    // find the POIs wrt location
                    self?.geocodePOIs(poi, location: self!.preferredSearchLocation, extent: nil)
                }
            } else {
                self.geocodePOIs(poi, location: self.preferredSearchLocation, extent: nil)
            }
        } else {
            if self.preferredSearchLocationTextField.text == self.currentLocationText {
                self.geocodePOIs(poi, location: self.mapView.locationDisplay.mapLocation, extent: nil)
            } else {
                self.geocodePOIs(poi, location: nil, extent: nil)
            }
        }
    }

    @IBAction private func searchInArea() {
        self.clearPreferredLocationInfo()
        self.geocodePOIs(self.poiTextField.text!, location: nil, extent: self.mapView.visibleArea!.extent)
    }

    // MARK: - Gesture recognizers

    @IBAction private func hideKeyboard() {
        self.view.endEditing(true)
    }

    @objc
    func showOverlayView() {
        self.overlayView.isHidden = false
    }

    @objc
    func hideOverlayView() {
        self.overlayView.isHidden = true
    }
}

extension FindPlaceViewController: UITableViewDataSource {
    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        var rows = suggestResults.count
        if selectedTextField == preferredSearchLocationTextField {
            rows += 1
        }
        animateTableView(expand: rows > 0)
        return rows
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "SuggestCell", for: indexPath)
        let isLocationTextField = (self.selectedTextField == self.preferredSearchLocationTextField)

        if isLocationTextField && indexPath.row == 0 {
            cell.textLabel?.text = self.currentLocationText
            cell.imageView?.image = UIImage(named: "CurrentLocationDisabledIcon")
            return cell
        }

        let rowNumber = isLocationTextField ? indexPath.row - 1 : indexPath.row
        let suggestResult = self.suggestResults[rowNumber]

        cell.textLabel?.text = suggestResult.label
        cell.imageView?.image = nil
        return cell
    }
}

extension FindPlaceViewController: UITableViewDelegate {
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        if self.selectedTextField == self.preferredSearchLocationTextField {
            if indexPath.row == 0 {
                self.preferredSearchLocationTextField.text = self.currentLocationText
            } else {
                let suggestResult = self.suggestResults[indexPath.row - 1]
                self.selectedSuggestResult = suggestResult
                self.preferredSearchLocation = nil
                self.selectedTextField.text = suggestResult.label
            }
        } else {
            let suggestResult = self.suggestResults[indexPath.row]
            self.selectedTextField.text = suggestResult.label
        }
        self.animateTableView(expand: false)
    }
}

extension FindPlaceViewController: AGSGeoViewTouchDelegate {
    func geoView(_ geoView: AGSGeoView, didTapAtScreenPoint screenPoint: CGPoint, mapPoint: AGSPoint) {
        // dismiss the callout if already visible
        self.mapView.callout.dismiss()

        // identify graphics at the tapped location
        self.mapView.identify(self.graphicsOverlay, screenPoint: screenPoint, tolerance: 12, returnPopupsOnly: false, maximumResults: 1) { (result: AGSIdentifyGraphicsOverlayResult) in
            if let error = result.error {
                print(error)
            } else if let graphic = result.graphics.first {
                // show callout for the first graphic in the array
                self.showCalloutForGraphic(graphic, tapLocation: mapPoint)
            }
        }
    }
}

extension FindPlaceViewController: UITextFieldDelegate {
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        let newString = (textField.text! as NSString).replacingCharacters(in: range, with: string)

        if textField == self.preferredSearchLocationTextField {
            self.selectedTextField = self.preferredSearchLocationTextField
            if !newString.isEmpty {
                self.fetchSuggestions(newString, suggestionType: .populatedPlace, textField: self.preferredSearchLocationTextField)
            }
            self.clearPreferredLocationInfo()
        } else {
            self.selectedTextField = self.poiTextField
            if !newString.isEmpty {
                self.fetchSuggestions(newString, suggestionType: .poi, textField: self.poiTextField)
            } else {
                self.canDoExtentSearch = false
                self.animateTableView(expand: false)
            }
        }
        return true
    }

    func textFieldShouldClear(_ textField: UITextField) -> Bool {
        if textField == self.preferredSearchLocationTextField {
            self.clearPreferredLocationInfo()
        } else {
            self.canDoExtentSearch = false
            self.animateTableView(expand: false)
        }
        return true
    }

    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        textField.resignFirstResponder()
        self.search()
        return true
    }

    func textFieldDidEndEditing(_ textField: UITextField) {
        self.animateTableView(expand: false)
    }
}

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