finding location from requestLocationUpdates() from GPS not working

Question

I am creating a map application, which gets location from GPS, i'm finding location from requestLocationUpdates(), but i'm not getting any response from GPS provider, however when i'am using network provider i'am getting location, can anyone help where i'm wrong,

Also i'am new to android app development, so i'll appreciate any tips to optimize my code(make more efficient with less mess),

Here's my code :

public void trackLocation(){
    if (ContextCompat.checkSelfPermission(activity.getApplicationContext(), Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
        locationManager = (LocationManager) activity.getSystemService(Context.LOCATION_SERVICE);
        boolean flag;
        Boolean dlg;
        flag = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
        if (flag) {
            Log.v("function", "onClick");
            myLocationListener = new MyLocationListener();
            dlg = true;
        } else {
            dlg = gpsDialog();
            progressBar.setVisibility(View.GONE);
        }

        Log.d("maps", "Requesting location updates");
        if(dlg) {
            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, myLocationListener);
        }
    }
}

public class MyLocationListener implements LocationListener {

    @Override
    public void onLocationChanged(Location location) {
        if (ActivityCompat.checkSelfPermission(MapsActivity.this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(MapsActivity.this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            return;
        }
        Log.d("maps", "on location changed : "+location.getLatitude() + "---"+ location.getLongitude());
        locationManager.removeUpdates(myLocationListener);
    }

    @Override
    public void onStatusChanged(String s, int i, Bundle bundle) {
        Log.d("maps" , "Status Changed");
    }

    @Override
    public void onProviderEnabled(String s) {
        Log.d("maps" , "Provider Enabled");
    }

    @Override
    public void onProviderDisabled(String s) {
        Log.d("maps" , "Provider Disabled");
    }
}

public Boolean gpsDialog(){
    AlertDialog.Builder builder = new AlertDialog.Builder(activity);
    builder.setMessage("Do you want to start GPS?")
            .setCancelable(false)
            .setTitle("GPS DISABLED")
            .setPositiveButton("Yes",
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int id) {
                            // finish the current activity
                            Intent myIntent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                            activity.startActivity(myIntent);
                            dialog.cancel();
                        }
                    })
            .setNegativeButton("No",
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int id) {
                            // cancel the dialog box
                            dialog.cancel();
                        }
                    });
    AlertDialog alert = builder.create();
    alert.show();
    progressBar.setVisibility(View.GONE);
    return false;
}

Answer 1

Google maps uses user's lastKnownLocation for location, If the lastknownLocation is unknown it takes time to fetch location through different provider say GPS or Network, whichever is easy. I would suggest to use lastKnownLocation as base location and update it with LocationListener. It is most optimized way of processing location.

       if (ActivityCompat.checkSelfPermission
                (this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                &&
                ActivityCompat.checkSelfPermission
                        (this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)
        {
            requestPermissions(new String[]{
                    Manifest.permission.ACCESS_COARSE_LOCATION,
                    Manifest.permission.ACCESS_FINE_LOCATION
            }, 1);

        }
        else {

            // enable location buttons
            googleMap.setMyLocationEnabled(true);
            googleMap.getUiSettings().setMyLocationButtonEnabled(true);

            // fetch last location if any from provider - GPS.
            final LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
            final Location loc = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
            //if last known location is not available
            if (loc == null) {

                final LocationListener locationListener = new LocationListener() {
                    @Override
                    public void onLocationChanged(final Location location) {

                        // getting location of user
                        final double latitude = location.getLatitude();
                        final double longitude = location.getLongitude();
                        //do something with Lat and Lng
                    }

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

                    @Override
                    public void onProviderEnabled(String provider) {
                        //when user enables the GPS setting, this method is triggered.
                    }

                    @Override
                    public void onProviderDisabled(String provider) {
                        //when no provider is available in this case GPS provider, trigger your gpsDialog here.
                    }
                };

                //update location every 10sec in 500m radius with both provider GPS and Network.

            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 10*1000, 500, locationListener);
                locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 10000, 500, locationListener);
            }
            else {
                //do something with last known location.
                // getting location of user
                final double latitude = loc.getLatitude();
                final double longitude = loc.getLongitude();
            }
        }

Permission handling:

     @Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    switch (requestCode) {

        case 1:
            if (grantResults[0] != PackageManager.PERMISSION_GRANTED){
                //do something
            }
        default:
            super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }
}

Answer 2

firstly check gps_enabled return true or not.

LocationManager lm = (LocationManager) mCtx
                .getSystemService(Context.LOCATION_SERVICE);

gps_enabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
network_enabled = lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER);

By this code you get accurate lat , long 


Location net_loc = null, gps_loc = null, finalLoc = null;

if (gps_enabled)
    gps_loc = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (network_enabled)
    net_loc = lm.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

if (gps_loc != null && net_loc != null) {

    if (gps_loc.getAccuracy() >= net_loc.getAccuracy())
        finalLoc = gps_loc;
    else
        finalLoc = net_loc;

        // I used this just to get an idea (if both avail, its upto you which you want to take as I taken location with more accuracy)

} else {

    if (gps_loc != null) {
        finalLoc = net_loc;
    } else if (net_loc != null) {
        finalLoc = gps_loc;
    }
}

Answer 3

Your code is correct. GPS usually doesn't give you any info within the building, if you try to test the app outside, you will get the results.