Learning: Getting users location - Asking for permission to access location

Android-Location.java

public class MainActivity extends AppCompatActivity {

    LocationManager locationManager;
    LocationListener locationListener;

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

        //  We are going to write Code to get Users Location:
        locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
        locationListener = new LocationListener() {
            //  This Listen For Location Changes.
            @Override
            public void onLocationChanged(Location location) {
                //  This Happens When Phone Moves.
                Log.i("Lord", String.valueOf(location));
            }
            @Override
            public void onStatusChanged(String provider, int status, Bundle extras) {
                //  This Happens when location service is enables Or disabled.
            }
            @Override
            public void onProviderEnabled(String provider) {
                //  This Happens when location service is enabled By user.
            }
            @Override
            public void onProviderDisabled(String provider) {
                //  This Happens when location service is disabled By user.
            }
        };

        //  If Device is running SDK < 23 ( This means Running android before MarshMellow )
        //  In This Case no checking is needed because the minSDKVersion is 23 but any way it is check like below.
        if(Build.VERSION.SDK_INT<23){
            Log.i("Lord", String.valueOf(Build.VERSION.SDK_INT));
        }

        //  Since Android MarshMellow(6) we need to Exactly request users Permission to use their location.
        //  We start by checking weather or not we have permission:
        //  We are checking if we have this Permission or Not.
        //  ContextCompat (ContextCompatibility) Class : this makes our  app compatible with pre-MarshMellow versions of android.
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            //  So this codes happen if we don't have permission,
            //  Asking for permission:
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1);
            //This Integer (1) is essentially a number that we can check at the other end that it was this particular request that was made.
        } else {
            //  We Have Permission so we ask for location.
            Log.i("Lord", "CheckSelfPermission Already Has Permission");
            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
        }
    }

    //  We are not doing anything after the permission asked, so to do that we have to prepare another method which is below.
    //  This is a method that already exist, so we have to override it.
    //  Request Code: the integer that we defined in the requestPermission part above.
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        Log.i("Lord", "onRequestPermissionsResult");
        Log.i("Lord", String.valueOf(grantResults.length) + "  " + grantResults[0]);
        if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            //  If both of condition above is true, then we have Permission.
            //  So if we have permission, we can start listening for the users location. to do that we need LocationManger.
            //  To actually do the Listening for the users location:
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
            }
        }
    }
}