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.

Prerequisites

The following are required for this tutorial:

An ArcGIS account to access API keys. If you don't have an account, sign up for free.
A development and deployment environment that meets the system requirements.
An IDE for Android development in Kotlin.

Steps

Open an Android Studio project

To start this tutorial, complete the Display a map tutorial. Or download and unzip the Display a map solution in a new folder.
Modify the old project for use in this new tutorial. Expand More info for instructions.
1. On your file system, delete the .idea folder, if present, at the top level of your project.
2. In the Android tool window, open app > res > values > strings.xml.
  In the <string name="app_name"> element, change the text content to Search for an address.
  strings.xml
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  1 2 3 4 5 6 7 <resources> <string name="app_name">Search for an address</string> </resources>
3. Create a <string name ="search_hint"> element to define the default text that initially shows in the search field.
  strings.xml
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  1 2 3 4 5 6 7 <resources> <string name="app_name">Search for an address</string> <string name="search_hint">Search for an address</string> </resources>
4. In the Android tool window, open Gradle Scripts > settings.gradle.
  Change the value of rootProject.name to "Search for an address".
  settings.gradle
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  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 rootProject.name = "Search for an address" include ':app'
5. Click File > Sync Project with Gradle files. Android Studio will recognize your changes and create a new .idea folder.

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 Android Studio: in the Android tool window, open app > java > com.example.app > MainActivity.

In the setApiKey() function, find the ApiKey.create() call and paste your API key inside the quotes, replacing YOUR_API_KEY.

MainActivity.kt
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    private fun setApiKey() {
        // It is not best practice to store API keys in source code. We have you insert one here
        // to streamline this tutorial.

        ArcGISEnvironment.apiKey = ApiKey.create("YOUR_API_KEY")

    }

Add import statements

Modify import statements to reference the packages and classes required for this tutorial.

In Android Studio, in the Android tool window, open app > java > com.example.app > MainActivity.

Replace app-specific import statements with the imports needed for this tutorial.

MainActivity.kt
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package com.example.app

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity

import android.util.Log
import android.widget.SearchView
import android.widget.Toast
import androidx.databinding.DataBindingUtil
import androidx.lifecycle.lifecycleScope

import com.arcgismaps.ApiKey
import com.arcgismaps.ArcGISEnvironment
import com.arcgismaps.Color
import com.arcgismaps.mapping.ArcGISMap
import com.arcgismaps.mapping.BasemapStyle
import com.arcgismaps.mapping.Viewpoint
import com.arcgismaps.mapping.symbology.HorizontalAlignment
import com.arcgismaps.mapping.symbology.SimpleMarkerSymbol
import com.arcgismaps.mapping.symbology.SimpleMarkerSymbolStyle
import com.arcgismaps.mapping.symbology.TextSymbol
import com.arcgismaps.mapping.symbology.VerticalAlignment
import com.arcgismaps.mapping.view.Graphic
import com.arcgismaps.mapping.view.GraphicsOverlay
import com.arcgismaps.mapping.view.MapView
import com.arcgismaps.tasks.geocode.GeocodeParameters
import com.arcgismaps.tasks.geocode.GeocodeResult
import com.arcgismaps.tasks.geocode.LocatorTask

import com.example.app.databinding.ActivityMainBinding
import kotlinx.coroutines.launch

Declare graphics overlay and locator task and initialize map view

A graphics overlay is a container for graphics. A locator task converts an address to a point. You will create the properties graphicsOverlay and locatorTask for use later in later steps. Next you will initialize the mapView.

In the MainActivitymethod, create a lazy property named graphicsOverlay that references a new GraphicsOverlay for storing geocode result graphics (address location and label).

Since graphicsOverlay is a lazy property, a GraphicsOverlay will not be created until the property is initialized, which occurs in the setupMap() method that you will modify shortly.

MainActivity.kt
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class MainActivity : AppCompatActivity() {

    private val activityMainBinding: ActivityMainBinding by lazy {
        DataBindingUtil.setContentView(this, R.layout.activity_main)
    }

    private val mapView: MapView by lazy {
        activityMainBinding.mapView
    }

    private val graphicsOverlay: GraphicsOverlay by lazy {
        GraphicsOverlay()
    }

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Create a property named locatorTask that references a new LocatorTask for geocoding an address.

MainActivity.kt
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class MainActivity : AppCompatActivity() {

    private val activityMainBinding: ActivityMainBinding by lazy {
        DataBindingUtil.setContentView(this, R.layout.activity_main)
    }

    private val mapView: MapView by lazy {
        activityMainBinding.mapView
    }

    private val graphicsOverlay: GraphicsOverlay by lazy {
        GraphicsOverlay()
    }

    private val geocodeServerUri = "https://geocode-api.arcgis.com/arcgis/rest/services/World/GeocodeServer"
    private val locatorTask = LocatorTask(geocodeServerUri)
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At the end of the setupMap method, initialize the mapView by calling the scope function apply and passing a lambda expression that does the following:

Assigns the local variable topographicMap to the map property
Creates a Viewpoint and passes it to setViewpoint()
Adds graphicsOverlay to the GeoView.graphicsOverlays collection.

Declared at the start of the MainActivity class, the lazy property graphicsOverlay is initialized at its first access, which is in this lambda expression. The new GraphicsOverlay is not created until now.

MainActivity.kt
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    // Set up your map here. You will call this method from onCreate().
    private fun setupMap() {
        lifecycle.addObserver(mapView)
        // create a map with the BasemapStyle topographic
        val topographicMap = ArcGISMap(BasemapStyle.ArcGISTopographic)

        mapView.apply {
            // set the map to be displayed in the layout's MapView
            map = topographicMap

            // set the viewpoint, Viewpoint(latitude, longitude, scale)
            setViewpoint(Viewpoint(34.0270, -118.8050, 72000.0))

            graphicsOverlays.add(graphicsOverlay)
        }

    }
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Add a UI for user input

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 activity_main.xml, add a SearchView element. This widget will display a search text field at the top of the app window.

activity_main.xml
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<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">
    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

        <SearchView
                android:id="@+id/searchView"
                android:layout_width="0dp"
                android:layout_height="0dp"
                android:queryHint="@string/search_hint"
                app:layout_constraintBottom_toTopOf="@+id/guideline"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" />
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In MainActivity.kt, create a setupSearchViewListener() method to handle user activity by changing the current address in the search field and submitting the search. In the first line, get the bound searchView with activityMainBinding.searchView. Then call setOnQueryTextListener() and pass an anonymous class that implements the SearchView.OnQueryTextListener interface.

MainActivity.kt
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    private fun setupSearchViewListener() {

        activityMainBinding.searchView.setOnQueryTextListener(object : SearchView.OnQueryTextListener {

        })
    }
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Implement the two methods of the SearchView.OnQueryTextListener interface: onQueryTextChange() and onQueryTextSubmit().

Returning false specifies the standard Android behavior.

MainActivity.kt
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    private fun setupSearchViewListener() {

        activityMainBinding.searchView.setOnQueryTextListener(object : SearchView.OnQueryTextListener {

            override fun onQueryTextChange(newText: String): Boolean {
                return false
            }

            override fun onQueryTextSubmit(query: String): Boolean {

                return false
            }

        })
    }
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In the onCreate() lifecycle method, add a setupSearchViewListener() call.

MainActivity.kt
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    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setApiKeyForApp()

        setupMap()

        setupSearchViewListener()

    }
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Create a function to geocode an address

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 refine the results, such as setting a maximum number of results or requesting additional attributes in the results.

Create a method named performGeocode().
Create a new GraphicsOverlay and initialize it by calling the scope function apply and passing a lambda expression that does the following:
- Adds the names of result attributes to the GeocodeParameters.resultAttributeNames collection. These are the names of attributes to be returned. An asterisk (*) indicates all attributes.
- Sets GeocodeParameters.maxResults to the maximum number of results to be returned. Results are ordered by score, so that the first result has the best match score (ranging from 0 for no match to 100 for the best match).
- Sets GeocodeParameters.outputSpatialReference to the spatial reference for result locations. By default, the output spatial reference is defined by the geocode service. For optimal performance when displaying the geocode result, you can ensure that returned coordinates match those of the map view by providing the map view's spatial reference.
When geocoding an address, you can optionally provide GeocodeParameters to control certain aspects of the geocoding operation and specify the kinds of results to return from the locator task. For a list of attributes returned with geocode results, see Geocoding service output in the ArcGIS services reference.
MainActivity.kt
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To find the location for the provided address, call LocatorTask.geocode(), passing the query (the address to find) and the geocodeParameters. Since geocode()is a suspend function, we call it from a a coroutine scope, created with lifecycleScope.launch().

MainActivity.kt
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    private fun performGeocode(query: String) {

        val geocodeParameters = GeocodeParameters().apply {
            resultAttributeNames.add("*")
            maxResults = 1
            outputSpatialReference = mapView.spatialReference.value
        }

        lifecycleScope.launch {
            locatorTask.geocode(query, geocodeParameters)

        }
    }
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The LocatorTask.geocode() function returns a Result<List<GeocodeResult>>, on which we call .onSuccess and pass a lambda. In the lambda, check that the list of GeocodeResults is not empty and then call displayResult(geocodeResults[0]) to display the first item in the list. In this tutorial, the maximum results parameter was set to 1, so you pass the first and only item in the geocodeResult list.

MainActivity.kt
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    private fun performGeocode(query: String) {

        val geocodeParameters = GeocodeParameters().apply {
            resultAttributeNames.add("*")
            maxResults = 1
            outputSpatialReference = mapView.spatialReference.value
        }

        lifecycleScope.launch {
            locatorTask.geocode(query, geocodeParameters)

                .onSuccess { geocodeResults: List<GeocodeResult> ->
                        if (geocodeResults.isNotEmpty()) {
                            displayResult(geocodeResults[0])
                        } else {
                            showError("No address found for the given query.")
                        }
                }.onFailure { error ->
                    showError("The locatorTask.geocode() call failed. " + error.message)
                }

        }
    }
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In the setupSearchViewListener() method, find the onQueryTextSubmit() method of the SearchView.OnQueryTextListener interface, and call performGeoCode(query).

MainActivity.kt
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    private fun setupSearchViewListener() {

        activityMainBinding.searchView.setOnQueryTextListener(object : SearchView.OnQueryTextListener {

            override fun onQueryTextChange(newText: String): Boolean {
                return false
            }

            override fun onQueryTextSubmit(query: String): Boolean {

                performGeocode(query)

                return false
            }

        })
    }
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Display the result

The result obtained from the geocode operation can be displayed by adding two graphics to the map view's graphics overlay: one graphic showing the address text and the other showing a red location marker.

Create a method named displayResult() and clear the graphics overlay of any previous result.

MainActivity.kt
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    private fun displayResult(geocodeResult: GeocodeResult) {

        // clear the overlay of any previous result
        graphicsOverlay.graphics.clear()

    }
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Create a TextSymbol for displaying the address text on the map. Then create a Graphic, passing the geocodeResult.displayLocation (the location on the map) and the textSymbol. Finally, add the graphic to the graphicsOverlay collection.

MainActivity.kt
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    private fun displayResult(geocodeResult: GeocodeResult) {

        // clear the overlay of any previous result
        graphicsOverlay.graphics.clear()

        // create a graphic to display the address text, and add styling to make it visually distinct
        // from the markerGraphic defined below
        val textSymbol = TextSymbol(
            text = geocodeResult.label,
            color = Color.black,
            size = 18f,
            horizontalAlignment = HorizontalAlignment.Center,
            verticalAlignment = VerticalAlignment.Bottom
        ).apply {
            offsetY = 8f
            haloColor = Color.white
            haloWidth = 2f
        }

        val textGraphic = Graphic(geocodeResult.displayLocation, textSymbol)
        graphicsOverlay.graphics.add(textGraphic)

    }
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Create a graphic to display a red marker symbol indicating the location on the map, and add the graphic to the graphicsOverlay collection.
MainActivity.kt
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