Netzwerkstandortanbieter gibt Standort nicht an Android

Ich entwickle eine kleine Android-Anwendung, in der ich mithilfe des Netzwerkanbieters den aktuellen Standort des Benutzers ermitteln möchte. Ich habe dies auf folgende Weise versucht, aber es gibt mir keine Ausgabe:

networklocationManager = (LocationManager) this
        .getSystemService(Context.LOCATION_SERVICE);
// Define a listener that responds to location updates
LocationListener networklocationListener = new LocationListener() {

    public void onLocationChanged(Location location) {
        Log.i("********************************",
                "this is my network location " + location);
        String Location_text = "NETWORK LOCATION latitude:"
                + location.getLatitude() + " longitude:"
                + location.getLatitude();
        network_location.setText(Location_text);
    }

    public void onStatusChanged(String provider, int status,
            Bundle extras) {}

    public void onProviderEnabled(String provider) {}

    public void onProviderDisabled(String provider) {}
};
// Register the listener with the Location Manager to receive location
// updates
networklocationManager
        .requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0,
                networklocationListener);

Ich habe Berechtigungen in meiner Manifest-Datei wie folgt gegeben

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

Gibt es etwas was mir fehlt? Ist das der richtige Weg? Brauche Hilfe. Vielen Dank...

public class MainActivity extends Activity implements LocationListener {

    private TextView latituteField;
    private TextView longitudeField;
    private LocationManager gpslocationManager;
    private LocationManager networklocationManager;
    private LocationManager networklocationManager1;
    private String provider;
    private TextView gps_location;
    private TextView network_location;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        gps_location = (TextView) findViewById(R.id.gps_location);
        network_location = (TextView) findViewById(R.id.network_location);
        networkLocation();
    }

    public void networkLocation() {
        networklocationManager = (LocationManager) this
                .getSystemService(Context.LOCATION_SERVICE);
        LocationListener networklocationListener = new LocationListener() {

            public void onLocationChanged(Location location) {
                Log.i("********************************",
                        "this is my network location " + location);
                String Location_text = "NETWORK LOCATION latitude:"
                        + location.getLatitude() + " longitude:"
                        + location.getLatitude();
                network_location.setText(Location_text);
            }

            public void onStatusChanged(String provider, int status,
                    Bundle extras) {}

            public void onProviderEnabled(String provider) {}

            public void onProviderDisabled(String provider) {}
        };
        networklocationManager
                .requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0,
                        networklocationListener);
    }
}

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