Learning : Maps and Getting Location

Android-Showing User Location On Map.java

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;
    LocationManager locationManager;
    LocationListener locationListener;
    LatLng newLocation;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

        //  Defining The LocationManager and LocationListener.
        locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
        locationListener = new LocationListener() {

            @Override
            public void onLocationChanged(Location location) {
                //  Removing Previous Markers Before adding the new one.
                mMap.clear();

                //  When Location Changes, a new marker is made on the location and the Camera Moves There.
                newLocation = new LatLng(location.getLatitude(), location.getLongitude());
                mMap.addMarker(new MarkerOptions().position(newLocation).title("You are Here"));
                mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(newLocation, 14));
            }

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

            }

            @Override
            public void onProviderEnabled(String provider) {

            }

            @Override
            public void onProviderDisabled(String provider) {

            }
        };
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        //  Checking For Permission, if we have it, then the request for location is sent, Else if we don't have permission, request for permission is made.
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1);
            return;
        }
        Log.i("Lord", "onMapReady Happens");
        //  Requesting Location.
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);

        //  Requesting Users Last Known Location. and Move Camera to that location.
        Location lastKnownLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        mMap.addMarker(new MarkerOptions().position(new LatLng(lastKnownLocation.getLatitude(), lastKnownLocation.getLongitude())).title("You are Here"));
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(lastKnownLocation.getLatitude(), lastKnownLocation.getLongitude()), 14));
    }

    //  this happens After request permission dialog is shown and user has allowed or denied access.
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        //  Checking to see if user has granted the permission or not,
        if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                Log.i("Lord", "onRequestPermissionsResult Happens");
                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
            }
        }
    }
}