Kotlin Android Google Map Current Location

To implement the Google Map in an Android application, we need to generate the Google Map API key. The process of creating the Google Map API key is described in Google Map Fixed Location tutorial.

In the previous tutorial of Kotlin Android Google Map Fixed Location, we have displayed the fixed Google location.

Now in this tutorial, we will display and place the marker at user's current location. To view the user's current location, we need to implement some Google Map interfaces and call there callbacks methods.

Google Map API Interface

OnMapRreadyCallback: This interface invokes when its instance is set on a MapFragment object. The onMapReady(GoogleMap) method of OnMapReadyCallback interface is called when the map is ready to use. In the onMapReady(GoogleMap) method, we can add markers, listeners, and other attributes.
LocationListener: This interface is used to receive the notification when the device location is changed. The abstract method onLocationChanged(Location) of LocationListener interface is called when the location has changed.
GoogleApiClient.ConnectionCallbacks: This interface provides the callbacks methods onConnected(Bundle) and onConnectionSuspended(int) which are called when the device is connected and disconnected respectively.
GoogleApiClient.OnConnectionFailedListener: This interface provides callbacks method onConnectionFailed(ConnectionResult) which is called when the error occurs while connecting the device to the service.

The isLocationEnabled property of GoogleMap is used to enable location layer, which allows the device to interact with the current location.

The tutorial using Java to display Google Map user's current location is described at Android Google Map Displaying Current Location.

Types of Google Map

There are four different types of Google map are available in map API. Each of them has different view of the map. These types are Normal, Hybrid, Satellite and Terrain.

googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
googleMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
googleMap.setMapType(GoogleMap.MAP_TYPE_SATELLITE);
googleMap.setMapType(GoogleMap.MAP_TYPE_TERRAIN);

Using Kotlin syntax, we will use the above Google map types as:

googleMap.mapType = MAP_TYPE_NONE
googleMap.mapType = MAP_TYPE_HYBRID
googleMap.mapType = MAP_TYPE_SATELLITE
googleMap.mapType = MAP_TYPE_TERRAIN

The detail about these map types are explain here.

activity_maps.xml

Add the following code in activity_maps.xml layout file.

<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/map"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="example.javatpoint.com.kotlingooglemapcurrentlocation.MapsActivity" />

strings.xml

<resources>
    <string name="app_name">Kotlin Google Map Current Location</string>
    <string name="title_activity_maps">Map Current Location</string>
</resources>

build.gradle

Add the Google Map Service and Google Location Service dependencies in build.gradle file.

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.google.android.gms:play-services-maps:11.8.0'
    compile 'com.google.android.gms:play-services-location:11.8.0'
    testImplementation 'junit:junit:4.12'
}

google_maps_api.xml

Place the Google Map API key in res/values/google_map_api.xml file.

<resources>
    <!--
     https://console.developers.google.com/flows/enableapi?apiid=maps_android_backend&keyType=CLIENT_SIDE_ANDROID&r=20:0B:71:3B:B2:46:75:A1:87:78:2E:4C:49:3F:E3:B6:FD:2D:76:D3%3Bexample.javatpoint.com.kotlingooglemapcurrentlocation

    Alternatively, follow the directions here:
    https://developers.google.com/maps/documentation/android/start#get-key
    -->
    <string name="google_maps_key" templateMergeStrategy="preserve" translatable="false">AIzaSyCuxsZ0D73o-REPLACE-WITH-YOUR-API</string>
</resources>

MapsActivity.kt

Add the following code in MapsActivity.kt class file.

package example.javatpoint.com.kotlingooglemapcurrentlocation

import android.content.pm.PackageManager
import android.location.Location
import android.os.Build
import android.os.Bundle
import android.support.v4.app.FragmentActivity
import android.support.v4.content.ContextCompat
import com.google.android.gms.common.ConnectionResult
import com.google.android.gms.common.api.GoogleApiClient
import com.google.android.gms.maps.CameraUpdateFactory
import com.google.android.gms.maps.GoogleMap
import com.google.android.gms.maps.OnMapReadyCallback
import com.google.android.gms.maps.SupportMapFragment
import com.google.android.gms.maps.model.BitmapDescriptorFactory
import com.google.android.gms.maps.model.LatLng
import com.google.android.gms.maps.model.Marker
import com.google.android.gms.maps.model.MarkerOptions
import android.Manifest
import android.os.Looper
import android.widget.Toast
import com.google.android.gms.location.*
import com.google.android.gms.location.FusedLocationProviderClient
import com.google.android.gms.location.LocationCallback
import com.google.android.gms.location.LocationRequest
import com.google.android.gms.location.LocationServices


class MapsActivity : FragmentActivity(), OnMapReadyCallback, LocationListener,
        GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener {

    private var mMap: GoogleMap? = null
    internal lateinit var mLastLocation: Location
    internal lateinit var mLocationResult: LocationRequest
    internal lateinit var mLocationCallback: LocationCallback
    internal var mCurrLocationMarker: Marker? = null
    internal var mGoogleApiClient: GoogleApiClient? = null
    internal lateinit var mLocationRequest: LocationRequest
    internal var mFusedLocationClient: FusedLocationProviderClient? = null


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_maps)
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        val mapFragment = supportFragmentManager
                .findFragmentById(R.id.map) as SupportMapFragment
        mapFragment.getMapAsync(this)

    }

    override fun onMapReady(googleMap: GoogleMap) {
        mMap = googleMap

        if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (ContextCompat.checkSelfPermission(this,
                            Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                buildGoogleApiClient()
                mMap!!.isMyLocationEnabled = true
            }
        } else {
            buildGoogleApiClient()
            mMap!!.isMyLocationEnabled = true
        }

    }

    @Synchronized
    protected fun buildGoogleApiClient() {
        mGoogleApiClient = GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API).build()
        mGoogleApiClient!!.connect()
    }

    override fun onConnected(bundle: Bundle?) {

        mLocationRequest = LocationRequest()
        mLocationRequest.interval = 1000
        mLocationRequest.fastestInterval = 1000
        mLocationRequest.priority = LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY
        if (ContextCompat.checkSelfPermission(this,
                        Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this)
            mFusedLocationClient?.requestLocationUpdates(mLocationRequest,mLocationCallback, Looper.myLooper())
        }
    }


    override fun onLocationChanged(location: Location) {

        mLastLocation = location
        if (mCurrLocationMarker != null) {
            mCurrLocationMarker!!.remove()
        }
        //Place current location marker
        val latLng = LatLng(location.latitude, location.longitude)
        val markerOptions = MarkerOptions()
        markerOptions.position(latLng)
        markerOptions.title("Current Position")
        markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN))
        mCurrLocationMarker = mMap!!.addMarker(markerOptions)

        //move map camera
        mMap!!.moveCamera(CameraUpdateFactory.newLatLng(latLng))
        mMap!!.animateCamera(CameraUpdateFactory.zoomTo(11f))

        //stop location updates
        if (mGoogleApiClient != null) {
            mFusedLocationClient?.removeLocationUpdates(mLocationCallback)
        }
    }

    override fun onConnectionFailed(connectionResult: ConnectionResult) {
        Toast.makeText(applicationContext,"connection failed", Toast.LENGTH_SHORT).show()
    }

    override fun onConnectionSuspended(p0: Int) {
        Toast.makeText(applicationContext,"connection suspended", Toast.LENGTH_SHORT).show()
    }
}  

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="example.javatpoint.com.kotlingooglemapcurrentlocation">

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
 
        <meta-data
            android:name="com.google.android.geo.API_KEY"
            android:value="@string/google_maps_key" />

        <activity
            android:name=".MapsActivity"
            android:label="@string/title_activity_maps">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Output: