/*
 * This example is useful if you only want to receive updates in this 
 * activity only, and have no use for location anywhere else.
 */
public class LocationActivity extends AppCompatActivity implements
        GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener {

    private GoogleApiClient mGoogleApiClient;
    private LocationRequest mLocationRequest;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();

        mLocationRequest = new LocationRequest()
                .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY) //GPS quality location points
                .setInterval(2000) //At least once every 2 seconds
                .setFastestInterval(1000); //At most once a second
    }

    @Override
    protected void onStart(){
        super.onStart();
        mGoogleApiClient.connect();
    }
    
    @Override
    protected void onResume(){
        super.onResume();
        //Permission check for Android 6.0+
        if(ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            if(mGoogleApiClient.isConnected()) {
                LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
            }
        }
    }
    
    @Override
    protected void onPause(){
        super.onPause();
        //Permission check for Android 6.0+
        if(ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            if(mGoogleApiClient.isConnected()) {
                LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
            }
        }
    }
    
    @Override
    protected void onStop(){
        super.onStop();
        mGoogleApiClient.disconnect();
    }

    @Override
    public void onConnected(@Nullable Bundle bundle) {
        if(ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
        }
    }

    @Override
    public void onConnectionSuspended(int i) {
        mGoogleApiClient.connect();
    }

    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
    }

    @Override
    public void onLocationChanged(Location location) {
        //Handle your location update code here
    }
}

/*
 * This example is useful if you have many different classes that should be 
 * receiving location updates, but want more granular control over which ones
 * listen to the updates.
 * 
 * For example, this activity will stop getting updates when it is not visible, but a database
 * class with a registered local receiver will continue to receive updates, until "stopUpdates()" is called here.
 *
 */
public class ExampleActivity extends AppCompatActivity {

    private InternalLocationReceiver mInternalLocationReceiver;

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        
        //Create internal receiver object in this method only.
        mInternalLocationReceiver = new InternalLocationReceiver(this);
    }

    @Override
    protected void onResume(){
        super.onResume();
        
        //Register to receive updates in activity only when activity is visible
        LocalBroadcastManager.getInstance(this).registerReceiver(mInternalLocationReceiver, new IntentFilter("googleLocation"));
    }

    @Override
    protected void onPause(){
        super.onPause();
        
        //Unregister to stop receiving updates in activity when it is not visible.
        //NOTE: You will still receive updates even if this activity is killed.
        LocalBroadcastManager.getInstance(this).unregisterReceiver(mInternalLocationReceiver);
    }

    //Helper method to get updates
    private void requestUpdates(){
        startService(new Intent(this, LocationService.class).putExtra("request", true));
    }

    //Helper method to stop updates
    private void stopUpdates(){
        startService(new Intent(this, LocationService.class).putExtra("remove", true));
    }

    /*
     * Internal receiver used to get location updates for this activity.
     * 
     * This receiver and any receiver registered with LocalBroadcastManager does
     * not need to be registered in the Manifest.
     *
     */
    private static class InternalLocationReceiver extends BroadcastReceiver{

        private ExampleActivity mActivity;

        InternalLocationReceiver(ExampleActivity activity){
            mActivity = activity;
        }

        @Override
        public void onReceive(Context context, Intent intent) {
            final ExampleActivity activity = mActivity;
            if(activity != null) {
                LocationResult result = intent.getParcelableExtra("result");
                //Handle location update here
            }
        }
    }
}

public class LocationService extends Service implements
        GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener {

    private GoogleApiClient mGoogleApiClient;
    private LocationRequest mLocationRequest;

    @Override
    public void onCreate(){
        super.onCreate();
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();

        mLocationRequest = new LocationRequest()
                .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY) //GPS quality location points
                .setInterval(2000) //At least once every 2 seconds
                .setFastestInterval(1000); //At most once a second
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId){
        super.onStartCommand(intent, flags, startId);
        //Permission check for Android 6.0+
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            if (intent.getBooleanExtra("request", false)) {
                if (mGoogleApiClient.isConnected()) {
                    LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, getPendingIntent());
                } else {
                    mGoogleApiClient.connect();
                }
            }
            else if(intent.getBooleanExtra("remove", false)){
                stopSelf();
            }
        }

        return START_STICKY;
    }

    @Override
    public void onDestroy(){
        super.onDestroy();
        if(mGoogleApiClient.isConnected()){
            LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, getPendingIntent());
            mGoogleApiClient.disconnect();
        }
    }
    
    private PendingIntent getPendingIntent(){
        
        //Example for IntentService
        //return PendingIntent.getService(this, 0, new Intent(this, **YOUR_INTENT_SERVICE_CLASS_HERE**), PendingIntent.FLAG_UPDATE_CURRENT);
        
        //Example for BroadcastReceiver
        return PendingIntent.getBroadcast(this, 0, new Intent(this, LocationReceiver.class), PendingIntent.FLAG_UPDATE_CURRENT);
    }

    @Override
    public void onConnected(@Nullable Bundle bundle) {
        //Permission check for Android 6.0+
        if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, getPendingIntent());
        }
    }

    @Override
    public void onConnectionSuspended(int i) {
        mGoogleApiClient.connect();
    }

    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {

    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}

public class LocationReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        if(LocationResult.hasResult(intent)){
            LocationResult locationResult = LocationResult.extractResult(intent);
            LocalBroadcastManager.getInstance(context).sendBroadcast(new Intent("googleLocation").putExtra("result", locationResult));
        }
    }
}