Usar GPStracker en Android

Hola aquí les dejo las 2 clases que he usado para hacer funcionar el GPS en Android está sacado de este enlace:

public class GPSTracker extends Service implements LocationListener{

private final Context context;

boolean isGPSEnabled = false;
boolean isNetworkEnabled = false;
boolean canGetLocation = false;

Location location;

double latitude;
double longitude;

private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10;
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1;

protected LocationManager locationManager;

public GPSTracker(Context context) {
    this.context = context;
    getLocation();
}

public Location getLocation() {
    try {
        locationManager = (LocationManager) context.getSystemService(LOCATION_SERVICE);

        isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);

        isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);

        if(!isGPSEnabled && !isNetworkEnabled) {

        } else {
            this.canGetLocation = true;

            if (isNetworkEnabled) {

                locationManager.requestLocationUpdates(
                        LocationManager.NETWORK_PROVIDER,
                        MIN_TIME_BW_UPDATES,
                        MIN_DISTANCE_CHANGE_FOR_UPDATES, this);

                if (locationManager != null) {
                    location = locationManager
                            .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

                    if (location != null) {

                        latitude = location.getLatitude();
                        longitude = location.getLongitude();
                    }
                }

            }

            if(isGPSEnabled) {
                if(location == null) {
                    locationManager.requestLocationUpdates(
                            LocationManager.GPS_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);

                    if(locationManager != null) {
                        location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);

                        if(location != null) {
                            latitude = location.getLatitude();
                            longitude = location.getLongitude();
                        }
                    }
                }
            }
        }

    } catch (Exception e) {
        e.printStackTrace();
    }

    return location;
}


public void stopUsingGPS() {
    if(locationManager != null) {
        locationManager.removeUpdates(GPSTracker.this);
    }
}

public double getLatitude() {
    if(location != null) {
        latitude = location.getLatitude();
    }
    return latitude;
}

public double getLongitude() {
    if(location != null) {
        longitude = location.getLongitude();
    }

    return longitude;
}

public boolean canGetLocation() {
    return this.canGetLocation;
}

public void showSettingsAlert() {
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(context);

    alertDialog.setTitle("GPS is settings");

    alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");

    alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which) {
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
            context.startActivity(intent);
        }
    });

    alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {

        @Override
        public void onClick(DialogInterface dialog, int which) {
            dialog.cancel();
        }
    });

    alertDialog.show();
}

@Override
public void onLocationChanged(Location arg0) {
    // TODO Auto-generated method stub
    this.location = location;
    getLatitude();
    getLongitude();
}

@Override
public void onProviderDisabled(String arg0) {
    // TODO Auto-generated method stub

}

@Override
public void onProviderEnabled(String arg0) {
    // TODO Auto-generated method stub

}

@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
    // TODO Auto-generated method stub

}

@Override
public IBinder onBind(Intent intent) {
    // TODO Auto-generated method stub
    return null;
}

}

Y esta es la clase principal:

public class MainActivity extends Activity {

GPSTracker gps;



@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    gps = new GPSTracker(MainActivity.this);

    if (gps.canGetLocation()) {
        double latitude = gps.getLatitude();
        double longitude = gps.getLongitude();
        Log.v("Your LOCATION is -" + "Lat:", latitude + "Long: " + longitude  );
        Toast.makeText(
                getApplicationContext(),
                "Your LOCATION is -nLat: " + latitude + "nLong: "
                        + longitude, Toast.LENGTH_LONG).show();
    } else {
        gps.showSettingsAlert();
    }





}
}