Android Geofencing with Google Maps

 Geo-fencing is a feature in Google Play Services that allows for checking when a user has entered or left a circular area. This feature is implemented using Google's Location Services, so it relies on location data from cellular towers, wireless networks and GPS. While this can be a powerful tool, it should be used conservatively as continuously polling for a users location can be taxing on the device battery. It should also be noted that Geo-fencing can take some time to register if the area has been entered or left, so you should plan accordingly when designing any apps that use this feature. For this post I have decided to put together an app that creates a Geo-fence around the users starting location and post a notification when the user enters or leaves the fence.


The first thing that should be done is to update the gradle.build file to include Google Play Services.

compile 'com.google.android.gms:play-services:6.5.87'

Next the manifest should be edited to allow the  permission in order to use the device's GPS functionality. Meta-data for the Google Play Services version should be included as a tag, and the service that will be used for handling what action to take on a Geo-fence event should be declared.

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

<meta-data
            android:name="com.google.android.gms.version"

            android:value="@integer/google_play_services_version" />

 Once the manifest file is set, then the main activity for the application should be set to implement GooglePlayServices connection callbacks and LocationClient Geofencing result and removal listeners. These are generally used for doing specific actions when PlayServices has connected or disconnected, as well as handling geofencing events.

public class MainActivity extends ActionBarActivity implements
        ConnectionCallbacks, OnConnectionFailedListener, ResultCallback<Status> {

    protected static final String TAG = "creating-and-monitoring-geofences";

    /**
     * Provides the entry point to Google Play services.
     */
    protected GoogleApiClient mGoogleApiClient;

    /**
     * The list of geofences used in this sample.
     */
    protected ArrayList<Geofence> mGeofenceList;

    /**
     * Used to keep track of whether geofences were added.
     */
    private boolean mGeofencesAdded;

    /**
     * Used when requesting to add or remove geofences.
     */
    private PendingIntent mGeofencePendingIntent;
   {


Verify that the device has Google Play Services available. If not, we can take action to alert the user to download it from the play store, or in this case simply end the activity.

private void verifyPlayServices() {
    switch ( GooglePlayServicesUtil.isGooglePlayServicesAvailable( this ) ) {
        case ConnectionResult.SUCCESS: {
            break;
        }
        case ConnectionResult.SERVICE_VERSION_UPDATE_REQUIRED: {
            finish();
        }
        default: {
            finish();
        }
    }
}


Once Play Services have been confirmed, we can create a reference to the device LocationClient, and create a PendingIntent to start our service (GeofencingService.class) that handles performing an action when the user interacts with a geofence.

private PendingIntent getGeofencePendingIntent() {
        // Reuse the PendingIntent if we already have it.
        if (mGeofencePendingIntent != null) {
            return mGeofencePendingIntent;
        }
        Intent intent = new Intent(this, GeofenceTransitionsIntentService.class);
        // We use FLAG_UPDATE_CURRENT so that we get the same pending intent back when calling
        // addGeofences() and removeGeofences().
        return PendingIntent.getService(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
    }

Next ,Start the Geo Fence request.

private GeofencingRequest getGeofencingRequest() {
        GeofencingRequest.Builder builder = new GeofencingRequest.Builder();

        // The INITIAL_TRIGGER_ENTER flag indicates that geofencing service should trigger a
        // GEOFENCE_TRANSITION_ENTER notification when the geofence is added and if the device
        // is already inside that geofence.
        builder.setInitialTrigger(GeofencingRequest.INITIAL_TRIGGER_ENTER);

        // Add the geofences to be monitored by geofencing service.
        builder.addGeofences(mGeofenceList);

        // Return a GeofencingRequest.
        return builder.build();
    }


To get full code Click Here