Retrieving Location with LocationServices API

Usage

The Fused Location API is a higher-level Google Play Services API that wraps the underlying location sensors like GPS. You can accomplish tasks like:

• Register for location connection events
• Connect to the location sensor
• Register for updates or accuracy changes
• Get last location

For even simpler location updates, check out this smart-location-lib locations API wrapper.

Installation

Fused location requires the use of the Google Play SDK. You must include the library in your app/build.gradle file:

dependencies {
    implementation 'com.google.android.gms:play-services-location:17.0.0'
}

To find the latest version to use refer to the official SDK setup instructions.

Adding Permissions

Add the following permissions to the AndroidManifest.xml:

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

This provides the ability to access location information at coarse and fine granularities. You can remove ACCESS_FINE_LOCATION this will still work with less precision.

Note: The permissions model has changed starting in Marshmallow. If your targetSdkVersion >= 23 and you are running on a Marshmallow (or later) device, you may need to enable runtime permissions. You can also read more about the runtime permissions changes here.

Connecting to the LocationServices API

Inside an Activity, put the following to connect and start receiving location updates:

private LocationRequest mLocationRequest;

private long UPDATE_INTERVAL = 10 * 1000;  /* 10 secs */
private long FASTEST_INTERVAL = 2000; /* 2 sec */

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    startLocationUpdates(); 
}

// Trigger new location updates at interval
protected void startLocationUpdates() {

    // Create the location request to start receiving updates
    mLocationRequest = new LocationRequest();
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    mLocationRequest.setInterval(UPDATE_INTERVAL);
    mLocationRequest.setFastestInterval(FASTEST_INTERVAL);

    // Create LocationSettingsRequest object using location request
    LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder();
    builder.addLocationRequest(mLocationRequest);
    LocationSettingsRequest locationSettingsRequest = builder.build();

    // Check whether location settings are satisfied
    // https://developers.google.com/android/reference/com/google/android/gms/location/SettingsClient
    SettingsClient settingsClient = LocationServices.getSettingsClient(this);
    settingsClient.checkLocationSettings(locationSettingsRequest);

    // new Google API SDK v11 uses getFusedLocationProviderClient(this)
    getFusedLocationProviderClient(this).requestLocationUpdates(mLocationRequest, new LocationCallback() {
      @Override
      public void onLocationResult(LocationResult locationResult) {
         // do work here
         onLocationChanged(locationResult.getLastLocation());
      }
    },
    Looper.myLooper());
}

and then register for location updates with onLocationChanged:

public void onLocationChanged(Location location) {
    // New location has now been determined
    String msg = "Updated Location: " +
        Double.toString(location.getLatitude()) + "," +
        Double.toString(location.getLongitude());
    Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();
    // You can now create a LatLng Object for use with maps
    LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
}

If you want the last known location, you can implement this function:

public void getLastLocation() {
    // Get last known recent location using new Google Play Services SDK (v11+)
    FusedLocationProviderClient locationClient = getFusedLocationProviderClient(this);

    locationClient.getLastLocation()
                .addOnSuccessListener(new OnSuccessListener<Location>() {
                    @Override
                    public void onSuccess(Location location) {
                        // GPS location can be null if GPS is switched off
                        if (location != null) {
                            onLocationChanged(location);
                        }
                    }
                })
                .addOnFailureListener(new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception e) {
                        Log.d("MapDemoActivity", "Error trying to get last GPS location");
                        e.printStackTrace();
                    }
                });
}

To allow Google Maps to show the icon that will take you to the GPS location, you will need to first request ACCESS_FINE_LOCATION permission and call setMyLocationEnabled:

@Override
public void onMapReady(GoogleMap googleMap) {

   if(checkPermissions()) {
     googleMap.setMyLocationEnabled(true);
   }
}

private boolean checkPermissions() {
  if (ContextCompat.checkSelfPermission(this,
     Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
     return true;
  } else {
     requestPermissions();
     return false;
  }
}

private void requestPermissions() {
        ActivityCompat.requestPermissions(this,
                new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                REQUEST_FINE_LOCATION);
}

For more information on the Fused Location API, refer to this Google guide.

For using maps check out the Cliffnotes for Maps or the Android Maps Tutorial. See a working source code example.

Troubleshooting Location Updates

Location updates should always be done using the FusedLocationProviderClient leveraging the LocationServices.API as shown above. Do not use the older Location APIs which are much less reliable. Even when using the correct FusedLocationApi, there are a lot of things that can go wrong. Consider the following potential issues:

• Did you add the necessary permissions? Make sure your app has INTERNET and ACCESS_COARSE_LOCATION permissions to ensure that location can be accessed as illustrated in the guide above.
• Are you trying to get location on the genymotion emulator? Ensure you've enabled GPS and configured a lat/lng properly. Try restarting the emulator if needed and re-enabling GPS or trying a device (or the official emulator) instead to rule out Genymotion specific issues.
• Are you failed to add Google Play Services Location dependencies when using Firebase? Firebase dependencies version is usually not up to date with recent Google Play Services, thus showing a conflict error when Gradle trying to get dependencies. To solve this, simply match Google Play Services Location version with your Firebase version.

You can also review the following troubleshooting resources:

• Beginner's Guide to Location
• Sample Treehouse Source Code

With this, you should have location updates working as expected.

References

• http://developer.android.com/training/location/retrieve-current.html
• https://developer.android.com/training/location/receive-location-updates.html
• http://www.vogella.com/articles/AndroidLocationAPI/article.html
• http://www.vogella.com/articles/AndroidGoogleMaps/article.html
• https://github.com/googlesamples/android-play-location/blob/master/LocationUpdates/app/src/main/java/com/google/android/gms/location/sample/locationupdates/MainActivity.java