how to get new lat long when current location change in android programmatically code example

Example: how to get current latlng in android stack overflow

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.TextView;

public class MainActivity extends Activity {

    TextView textview;

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

        // check if GPS enabled
        GPSTracker gpsTracker = new GPSTracker(this);

        if (gpsTracker.getIsGPSTrackingEnabled())
        {
            String stringLatitude = String.valueOf(gpsTracker.latitude);
            textview = (TextView)findViewById(R.id.fieldLatitude);
            textview.setText(stringLatitude);

            String stringLongitude = String.valueOf(gpsTracker.longitude);
            textview = (TextView)findViewById(R.id.fieldLongitude);
            textview.setText(stringLongitude);

            String country = gpsTracker.getCountryName(this);
            textview = (TextView)findViewById(R.id.fieldCountry);
            textview.setText(country);

            String city = gpsTracker.getLocality(this);
            textview = (TextView)findViewById(R.id.fieldCity);
            textview.setText(city);

            String postalCode = gpsTracker.getPostalCode(this);
            textview = (TextView)findViewById(R.id.fieldPostalCode);
            textview.setText(postalCode);

            String addressLine = gpsTracker.getAddressLine(this);
            textview = (TextView)findViewById(R.id.fieldAddressLine);
            textview.setText(addressLine);
        }
        else
        {
            // can't get location
            // GPS or Network is not enabled
            // Ask user to enable GPS/network in settings
            gpsTracker.showSettingsAlert();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.varna_lab_geo_locations, menu);
        return true;
    }
}