GPS location returns only null (0.0.0.0)

Question

I have an application for Android devices, with several addresses. By clicking on any address, I wanted to take the user’s current location and play link google maps http://maps.google.com/maps?&saddr=", together with the destination coordinates.

However, the current "latitude" and "longitude" results only return "0.0".

Can someone help me?

public class Guaruja extends Activity implements LocationListener {

Button bttela2;
TextView TextView1;
TextView t1;
Uri uri;
    protected LocationManager locationManager;
    protected LocationListener locationListener;
    protected Context context;
String provider;
double latitude, longitude;




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



    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);


    TextView1 = (TextView) findViewById (R.id.TextView1);



    TextView1.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {



            String lati = String.valueOf(latitude);
            String longi = String.valueOf(longitude);
            String firt = "http://maps.google.com/maps?&saddr=";
            String secord="&daddr=-23.990624, -46.282269";
            String virgula=",";
            String url= firt+lati+virgula+longi+secord;
               uri=Uri.parse(url);
               Intent intent = new Intent(Intent.ACTION_VIEW, uri);
               startActivity(intent);
        }


    });



}


public void onLocationChanged(Location location){

  if(location!= null){
       latitude = location.getLatitude() * 1E6;
       longitude = location.getLongitude() * 1E6;

}
    }

EDITED

---

I spent several days "stuck" in this code, because always the location returned me 0.0 and threw me in the Pacific Ocean. I managed to solve it, although I didn’t use the tracking code itself. As you can see in the code above, I used the Google Maps URL to take the user to the map with the coordinates set by me. After a search on this URL, I found a solution that worked very well for me, I used the link like this: "http://maps.google.com/maps?&saddr=&daddr=-23.990624,-46.282269&sensor=TRUE", i.e., I just left the starting coordinates blank ("&saddr=").

Thank you all for your help.

Answer 1

locationManager.requestLocationUpdates(Locationmanager.GPS_PROVIDER, 1000, 1, this); lets you greatly improve your application.

Answer 2

I spent several days "stuck" in this code, because always the location returned me 0.0 and threw me in the Pacific Ocean. I managed to solve it, although I didn’t use the tracking code itself. As you can see in the code above, I used the Google Maps URL to take the user to the map with the coordinates set by me. After a search on this URL, I found a solution that worked very well for me, I used the link like this: "http://maps.google.com/maps?&saddr=&daddr=-23.990624,-46.282269&sensor=TRUE", i.e., I just left the starting coordinates blank ("&saddr=").

Thank you all for your help.

Answer 3

You need to wait for the GPS to calibrate. Creates a loading structure that alerts you after the onLocationChanged(Location location) is different from null. Example:

public void onLocationChanged(Location location){


    if(location!= null){
       latitude = location.getLatitude()*1E6;
       longitude = location.getLongitude()*1E6;
       dialog.dismiss();// Aqui você fecha o dialog. O gps foi calibrado
    }