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Fairly new to Android development, following a tutorial on Udemy. Getting a nullpointerexception on an object, even though it prints the value to the log. Looks like it's the driverLocation object that's messing up, but I have tried to initialize it in the declaration and in onCreate. I am using parse.com to save data.

Below is the code from the java file, or activity this error occurs. There is 4 other java files in the project, so tell me if I should post more. Posted log messages below code. Been stuck on this for a while, and there is most certainly something obvious iv'e forgotten.

public class YourLocation extends FragmentActivity implements OnMapReadyCallback, LocationListener {

Location location;
private GoogleMap mMap;
LocationManager locationManager;
String provider;
TextView infoTextView;
Button requestDriverButton;
Boolean requestActive;
String driverUsername = "";
ParseGeoPoint driverLocation = new ParseGeoPoint(10,10);
Handler handler = new Handler();
public void requestDriver(View view) {

    if (requestActive == false) {

        Toast.makeText(getApplicationContext(), "Driver Requested", Toast.LENGTH_SHORT).show();

        final ParseObject request = new ParseObject("Request");
        request.put("requesterUsername", ParseUser.getCurrentUser().getUsername());

        ParseACL parseACL = new ParseACL();
        parseACL.setPublicWriteAccess(true);
        parseACL.setPublicReadAccess(true);
        request.setACL(parseACL);

        request.saveInBackground(new SaveCallback() {
            @Override
            public void done(ParseException e) {
                if (e == null) {
                    infoTextView.setText("Waiting for driver...");
                    requestDriverButton.setText("Cancel ride");
                    requestActive = true;
                    updateLocation(location);
                }
            }
        });

    } else {
        infoTextView.setText("Ride cancelled");
        requestDriverButton.setText("Request Driver");
        requestActive = false;

        ParseQuery<ParseObject> query = new ParseQuery<ParseObject>("Request");
        query.whereEqualTo("requesterUsername", ParseUser.getCurrentUser().getUsername());
        query.findInBackground(new FindCallback<ParseObject>() {
            @Override
            public void done(List<ParseObject> objects, ParseException e) {
                if (e == null) {
                    if (objects.size() > 0) {
                        for (ParseObject object : objects) {
                            object.deleteInBackground(new DeleteCallback() {
                                @Override
                                public void done(ParseException e) {
                                    Toast.makeText(getApplicationContext(), "Ride Cancelled", Toast.LENGTH_SHORT).show();
                                }
                            });
                        }
                    }
                }
            }
        });
    }

}

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

    infoTextView = (TextView) findViewById(R.id.infoTextView);
    requestDriverButton = (Button) findViewById(R.id.requestDriver);

    locationManager = (LocationManager) getSystemService(LOCATION_SERVICE); //Context.LOCATION_SERVICE??
    provider = locationManager.getBestProvider(new Criteria(), false);

    locationManager.requestLocationUpdates(provider, 400, 1, this);

    requestActive = false;
}

@Override
protected void onResume() {
    super.onResume();

    locationManager.requestLocationUpdates(provider, 400, 1, this);
}

@Override
protected void onPause() {
    super.onPause();

    locationManager.removeUpdates(this);
}

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

    location = locationManager.getLastKnownLocation(provider);

    if (location != null) {

        updateLocation(location);
    }
}

public void updateLocation(final Location location) {

    mMap.clear();

    if (requestActive == false) {
        ParseQuery<ParseObject> query = ParseQuery.getQuery("Request");
        query.whereEqualTo("requesterUsername", ParseUser.getCurrentUser().getUsername());
        query.findInBackground(new FindCallback<ParseObject>() {
            @Override
            public void done(List<ParseObject> objects, ParseException e) {
                if (e == null) {
                    if (objects.size() > 0) {
                        for (ParseObject object : objects) {
                            requestActive = true;
                            infoTextView.setText("Waiting for driver...");
                            requestDriverButton.setText("Cancel ride");

                            if (object.get("driverUsername") != null) {

                                driverUsername = object.getString("driverUsername");
                                infoTextView.setText("A driver is on the way");
                                requestDriverButton.setVisibility(View.INVISIBLE);

                            }
                        }
                    }
                }
            }
        });
    }

    if (driverUsername.equals("")) {

        mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(location.getLatitude(), location.getLongitude()), 10));

        mMap.addMarker(new MarkerOptions().position(new LatLng(location.getLatitude(), location.getLongitude())).title("Your Location"));
    }

    if (requestActive == true) {

        if (!driverUsername.equals("")) {

            ParseQuery<ParseUser> query = ParseUser.getQuery();
            query.whereEqualTo("username", driverUsername);
            query.findInBackground(new FindCallback<ParseUser>() {
                @Override
                public void done(List<ParseUser> objects, ParseException e) {
                    if (e == null) {
                        if (objects.size() > 0) {
                            for (ParseUser driver : objects) {
                                driverLocation = driver.getParseGeoPoint("location");
                            }
                        }
                    }
                }
            });

            Log.i("test", driverLocation.toString());

            Log.i("latitude", String.valueOf(driverLocation.getLatitude()));
            Log.i("longitude", String.valueOf(driverLocation.getLongitude()));

            if (driverLocation.getLatitude() != 0.0 && driverLocation.getLongitude() != 0.0) {
                Log.i("app", driverLocation.toString());

                Double distanceInKM = driverLocation.distanceInKilometersTo(new ParseGeoPoint(location.getLatitude(), location.getLongitude()));

                NumberFormat format = new DecimalFormat("#0.00");

                infoTextView.setText("Your driver is " + format.format(distanceInKM) + " km away");

                LatLngBounds.Builder builder = new LatLngBounds.Builder();

                ArrayList<Marker> markers = new ArrayList<>();

                markers.add(mMap.addMarker(new MarkerOptions().position(new LatLng(driverLocation.getLatitude(), driverLocation.getLongitude())).icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_CYAN)).title("Driver Location")));

                markers.add(mMap.addMarker(new MarkerOptions().position(new LatLng(location.getLatitude(), location.getLongitude())).title("Your Location")));

                for (Marker marker : markers) {
                    builder.include(marker.getPosition());
                }

                LatLngBounds bounds = builder.build();

                int padding = 300;
                CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngBounds(bounds, padding);

                mMap.animateCamera(cameraUpdate);
            }

        }

        final ParseGeoPoint userLocation = new ParseGeoPoint(location.getLatitude(), location.getLongitude());

        ParseQuery<ParseObject> query1 = new ParseQuery<ParseObject>("Request");
        query1.whereEqualTo("requesterUsername", ParseUser.getCurrentUser().getUsername());
        query1.findInBackground(new FindCallback<ParseObject>() {
            @Override
            public void done(List<ParseObject> objects, ParseException e) {
                if (e == null) {
                    for (ParseObject object : objects) {
                        object.put("requesterLocation", userLocation);
                        object.saveInBackground();
                    }
                }
            }
        });

    }

    handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            updateLocation(location);
        }
    }, 2000);

}

@Override
public void onLocationChanged(Location location) {

    mMap.clear();

    updateLocation(location);

}

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

}

@Override
public void onProviderEnabled(String provider) {

}

@Override
public void onProviderDisabled(String provider) {

}
}

Logcat:

11-01 23:30:43.447 11709-11709/com.parse.starter I/test: ParseGeoPoint[10.000000,10.000000]
11-01 23:30:43.447 11709-11709/com.parse.starter I/latitude: 10.0
11-01 23:30:43.447 11709-11709/com.parse.starter I/longitude: 10.0
11-01 23:30:43.447 11709-11709/com.parse.starter I/app: ParseGeoPoint[10.000000,10.000000]
11-01 23:30:43.967 11709-11709/com.parse.starter D/AndroidRuntime: Shutting down VM
11-01 23:30:43.968 11709-11709/com.parse.starter E/AndroidRuntime: FATAL EXCEPTION: main
11-01 23:30:43.968 11709-11709/com.parse.starter E/AndroidRuntime: Process: com.parse.starter, PID: 11709
11-01 23:30:43.968 11709-11709/com.parse.starter E/AndroidRuntime: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.parse.ParseGeoPoint.toString()' on a null object reference
11-01 23:30:43.968 11709-11709/com.parse.starter E/AndroidRuntime:     at com.parse.starter.YourLocation.updateLocation(YourLocation.java:218)
11-01 23:30:43.968 11709-11709/com.parse.starter E/AndroidRuntime:     at com.parse.starter.YourLocation$6.run(YourLocation.java:275)
11-01 23:30:43.968 11709-11709/com.parse.starter E/AndroidRuntime:     at android.os.Handler.handleCallback(Handler.java:739)
11-01 23:30:43.968 11709-11709/com.parse.starter E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:95)
11-01 23:30:43.968 11709-11709/com.parse.starter E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:148)
11-01 23:30:43.968 11709-11709/com.parse.starter E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5417)
11-01 23:30:43.968 11709-11709/com.parse.starter E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method)
11-01 23:30:43.968 11709-11709/com.parse.starter E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
11-01 23:30:43.968 11709-11709/com.parse.starter E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
ArtKorchagin
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Emil Øgård
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  • Possible duplicate of [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) – Yassin Hajaj Nov 01 '15 at 23:25

2 Answers2

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I don't see where you defined driverLocation in onCreate, so it's still possible after onCreate is called that in your updateLocation method, if either "if (e == null)" or "if (objects.size() > 0)" return false, driverLocation will not be defined, and it will be null, therefore causing driverLocation.toString() to throw NullPointerException.

I would suggest declaring driverLocation at the top of the class where you have it now:

ParseGeoPoint driverLocation;

And then define it in the onCreate method so it will always be defined (not null).

driverLocation = new ParseGeoPoint(10,10);
SRutherford
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Looks like Iv'e just messed up something on Parse. For those wondering, I set the value of driverLocation to driver.getParseGeoPoint("location"), which was null, so there it was. Updated something in Parse, and it worked like a charm. Thanks for your effort people!

Emil Øgård
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