Search for an address

Learn how to find an address or place with a search bar and the Geocoding service.

Geocoding is the process of converting address or place text into a location. The Geocoding service can search for an address or a place and perform reverse geocoding.

In this tutorial, you use a search bar in the user interface to access the Geocoding service and search for addresses and places.

To learn how to use the Geocoding service to reverse geocode, visit the Reverse geocode tutorial.

Prerequisites

The following are required for this tutorial:

An ArcGIS account to access your API keys. If you don't have an account, sign up for free.
Your system meets the system requirements.

Steps

Open the Xcode project

To start the tutorial, complete the Display a map tutorial or download and unzip the solution.
Open the .xcodeproj file in Xcode.

If you downloaded the solution project, set your API key.

An API Key enables access to services, web maps, and web scenes hosted in ArcGIS Online.

Go to your developer dashboard to get your API key. For these tutorials, use your default API key. It is scoped to include all of the services demonstrated in the tutorials.
In Xcode, in the Project Navigator, click AppDelegate.swift.

In the editor, set the APIKey property on the AGSArcGISRuntimeEnvironment with your API key.

AppDelegate.swift
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    func application(_ application: UIApplication,
                     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Note: it is not best practice to store API keys in source code.
        // The API key is referenced here for the convenience of this tutorial.

        AGSArcGISRuntimeEnvironment.apiKey = "YOUR_API_KEY"

        return true
    }
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Add a search bar to the UI

To search an address using the application, add a UI element to prompt the user for text input. The text input will be used as the geocode search text in a later step.

In Xcode, in the Project Navigator, click ViewController.swift.

In the editor, extend ViewController to conform to the UISearchBarDelegate protocol.

The UISearchBarDelegate will allow ViewController to receive user interaction messages from a UISearchBar.

ViewController.swift
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extension ViewController: UISearchBarDelegate {

}

Define a private method named setupSearchBar(). In setupSearchBar() create an UISearchBar with these initial values and assign it to navigationItem.titleView.

ViewController.swift
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    private func setupSearchBar() {
        navigationItem.titleView = {
            let searchBar = UISearchBar()
            searchBar.delegate = self
            searchBar.showsCancelButton = true
            searchBar.placeholder = "Search for an address"
            return searchBar
        }()
    }
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In Xcode, in the Project Navigator, click Main.storyboard.
In the editor, select ViewController. In the menu bar, click Editor > Embed In > Navigation Controller.
Embedding ViewController within a Navigation Controller will place a navigation bar at the top of ViewController. Inside the navigation bar you will find the search bar.
In Xcode, in the Project Navigator, click ViewController.swift.

In the editor, in the viewDidLoad() method, call setupSearchBar().

ViewController.swift
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    override func viewDidLoad() {
        super.viewDidLoad()
        setupMap()

        setupSearchBar()

    }
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Add graphics to the map view

A graphics overlay is a container for graphics. Graphics are added as a visual means to display the search result on the map.

Create a private AGSGraphic property named textGraphic. This graphic will be used to display the result's text label.

An AGSTextSymbol is used to display text at a location on the map view.

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    private let textGraphic: AGSGraphic = {
        let textSymbol = AGSTextSymbol(
            text: "",
            color: .black,
            size: 14,
            horizontalAlignment: .center,
            verticalAlignment: .bottom
        )
        return AGSGraphic(geometry: nil, symbol: textSymbol)
    }()
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Create a private AGSGraphic property named markerGraphic. This graphic will be used to display the result's location.

An AGSSimpleMarkerSymbol is used to display a location on the map view.

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    private let markerGraphic: AGSGraphic = {
        let markerSymbol = AGSSimpleMarkerSymbol(
            style: .square,
            color: .red,
            size: 12
        )
        return AGSGraphic(geometry: nil, symbol: markerSymbol)
    }()
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Define a private method named setupGraphics(). In setupGraphics() create an AGSGraphicsOverlay. Append textGraphic and markerGraphic to the graphics overlay then add the graphics overlay to the map view.

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    private func setupGraphics() {
        let graphicsOverlay = AGSGraphicsOverlay()
        graphicsOverlay.graphics.addObjects(from: [textGraphic, markerGraphic])
        mapView.graphicsOverlays.add(graphicsOverlay)
    }
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Because textGraphic and markerGraphic haven't yet specified a geometry, they will not be visible.

In the viewDidLoad() method, call setupGraphics().

ViewController.swift
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    override func viewDidLoad() {
        super.viewDidLoad()
        setupMap()

        setupSearchBar()

        setupGraphics()

    }
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Define app geocode results status

The app will leverage a state-machine design pattern to ensure the contents of the map reflect the state of the search result. This design pattern supports wrangling multiple asynchronous requests to the world geocoding service into a single state variable result, ensuring the reliability of search results.

Define an enum named ResultStatus with two cases. The first case, none, is used when there is no result or an error is returned. The second case, result, is used when a result is found.

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    enum ResultStatus {
        case none
        case result(String, AGSPoint)
    }
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Create a ResultStatus property named status. Setting this property will update textGraphic and markerGraphic with values from the result.

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    enum ResultStatus {
        case none
        case result(String, AGSPoint)
    }

    var status: ResultStatus = .none {
        didSet {
            switch status {
            case .none:
                (textGraphic.symbol as! AGSTextSymbol).text = ""
                textGraphic.geometry = nil
                markerGraphic.geometry = nil
            case .result(let title, let location):
                (textGraphic.symbol as! AGSTextSymbol).text = title
                textGraphic.geometry = location
                markerGraphic.geometry = location
            }
        }
    }
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Create a locator task with geocode parameters

Geocoding is implemented with a locator, typically created by referencing a service such as the Geocoding service or, for offline geocoding, by referencing locator data contained in a mobile package. Geocoding parameters can be used to fine-tune the results, such as setting the maximum number of results or requesting additional attributes in the results.

Create a private AGSLocatorTask property named locator with the Geocoding service URL.
A locator task is used to convert an address to a point (geocode) or vice-versa (reverse geocode). An address includes any type of information that distinguishes a place. A locator involves finding matching locations for a given address. Reverse-geocoding is the opposite and finds the closest address for a given point.
ViewController.swift
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Create a private optional AGSCancelable property named currentGeocodeOperation that will maintain a reference to the geocode operation. If the user submits a second query before the current one completes, it can be used to cancel the operation.

ViewController.swift
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    private let locator = AGSLocatorTask(
        url: URL(string: "https://geocode-api.arcgis.com/arcgis/rest/services/World/GeocodeServer")!
    )

    private var currentGeocodeOperation: AGSCancelable?

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Define a private method named geocode(with searchText: String) and cancel the current geocode operation, if one exists.

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    private let locator = AGSLocatorTask(
        url: URL(string: "https://geocode-api.arcgis.com/arcgis/rest/services/World/GeocodeServer")!
    )

    private var currentGeocodeOperation: AGSCancelable?

    private func geocode(with searchText: String) {
        currentGeocodeOperation?.cancel()

    }
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Create new AGSGeocodeParameters, and assign it to the geocodeParameters property. Specify the geocode's attributes as follows:
- Specify which attributes to return with resultAttributeNames. * is used to return all attributes.
- Set the maximum number of results to be returned with maxResults. In this tutorial, only return the best match by passing in 1. Results are ordered by score, so just returning the first result will return the highest scoring result.
- Set the spatial reference with outputSpatialReference. By default the output spatial reference is determined by the geocode service. For optimal performance when displaying the geocode result, ensure the returned coordinates match those of the map view by providing mapView.spatialReference as a parameter.
  When geocoding an address, you can optionally provide AGSGeocodeParameters to control certain aspects of the geocoding operation, and specify the kinds of results to return from the locator task.
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Perform the geocode operation by calling geocodeWithSearchText:parameters:completion:() and supplying the search query and the geocode parameters. Handle the operation's completion and set the result status accordingly. The result obtained from the geocode operation will be displayed as a graphic in the map view's graphics overlay.

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    private func geocode(with searchText: String) {
        currentGeocodeOperation?.cancel()

        let parameters: AGSGeocodeParameters = {
            let parameters = AGSGeocodeParameters()
            parameters.resultAttributeNames = ["*"]
            parameters.maxResults = 1
            parameters.outputSpatialReference = mapView.spatialReference
            return parameters
        }()

        currentGeocodeOperation = self.locator.geocode(withSearchText: searchText, parameters: parameters) { [weak self] (results, error) in
            guard let self = self else { return }
            if let error = error {
                self.status = .none
                print(error.localizedDescription)
                return
            } else if let firstResult = results?.first,
                      let extent = firstResult.extent,
                      let location = firstResult.displayLocation {
                self.status = .result(firstResult.label, location)
                self.mapView.setViewpointGeometry(extent)
            } else {
                self.status = .none
                print("No results found for \(searchText).")
            }
        }

    }
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Hook up the search bar to the geocode operation

Find the ViewController extension of UISearchBarDelegate and introduce the searchBarSearchButtonClicked(_:) search bar delegate method. Use this method to know when the user presses Search and to perform the geocode operation.

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extension ViewController: UISearchBarDelegate {

    func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
        searchBar.resignFirstResponder()
        guard let searchText = searchBar.text, !searchText.isEmpty else {
            print("Nothing to search!")
            return
        }
        geocode(with: searchText)
    }

}

Introduce the searchBarCancelButtonClicked(_:) search bar delegate method. Use this method to know when the user presses Cancel and to dismiss the keyboard.

ViewController.swift
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extension ViewController: UISearchBarDelegate {

    func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
        searchBar.resignFirstResponder()
        guard let searchText = searchBar.text, !searchText.isEmpty else {
            print("Nothing to search!")
            return
        }
        geocode(with: searchText)
    }

    func searchBarCancelButtonClicked(_ searchBar: UISearchBar) {
        searchBar.resignFirstResponder()
    }

}

Press <Command+R> to run the app.
If you are using the Xcode simulator your system must meet these minimum requirements: macOS Big Sur 11.3, Xcode 13, iOS 13. If you are using a physical device, then refer to the system requirements.

You should see a search box on the top left of the map. Search for an address by entering an address and press Search on the keyboard. The result of the search should display on the map as a red square.

What's next?

Learn how to use additional API features, ArcGIS location services, and ArcGIS tools in these tutorials:

Solution

Download solution

Estimated time

15 minutes

ArcGIS Runtime API for iOS