final String credentials = Credentials.basic(etUserName.getText().toString(), etPassword.getText().toString());
                final Request request = new Request.Builder()
                        .url("")
                        .get()
                        .addHeader("authorization", credentials)
                        .addHeader("cache-control", "no-cache")
                        .build();

                new AsyncTask<Request, Integer, String>(){
                    @Override
                    protected String doInBackground(Request... params) {
                        OkHttpClient client = new OkHttpClient();
                        try {
                            Response response = client.newCall(request).execute();
                            String responseBody = response.body().string();
                            if (response.isSuccessful()) {
                                return responseBody;
                            }

                        } catch (Exception e) {
                            Log.v(TAG, e.toString());
                        }
                        return null;
                    }

                    @Override
                    protected void onPostExecute(String responseBody) {

                        if (responseBody != null) {
                            if (createTokenSharedPreferences(responseBody, etUserName.getText().toString())) {
                                Intent bNextIntent = new Intent(LoginActivity.this, MainActivity.class);
                                startFirebaseServices();
                                bNextIntent.putExtra("userName", etUserName.getText());
                                bNextIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
                                LoginActivity.this.startActivity(bNextIntent);
                                return;
                            }
                        }
                        Log.e(TAG, "Login failed!");
                        etPassword.setText("");
                        v.setClickable(true);
                        Toast.makeText(getApplicationContext(), "Wrong credentials. Please try again.", Toast.LENGTH_LONG).show();
                    }

                    private boolean createTokenSharedPreferences(String responseBody, String userName) {
                        try {
                            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
                            DocumentBuilder db = dbf.newDocumentBuilder();
                            InputSource userInfo = new InputSource(new StringReader(responseBody));
                            Document doc = db.parse(userInfo);

                            NodeList nodeList = doc.getElementsByTagName("token");

                            for (int i = 0; i < nodeList.getLength(); i++) {
                                Node node = nodeList.item(i);

                                Element firstElement = (Element) node;
                                NodeList valueList = firstElement.getElementsByTagName("value");
                                Element valueElement = (Element) valueList.item(0);
                                valueList = valueElement.getChildNodes();

                                NodeList expiresList = firstElement.getElementsByTagName("expires-in");
                                Element expiresElement = (Element) expiresList.item(0);
                                expiresList = expiresElement.getChildNodes();

                                SharedPreferences.Editor editor = getSharedPreferences(User.LEVEL_1_AUTH_TOKEN, MODE_PRIVATE).edit();

                                editor.putString("value", (valueList.item(0)).getNodeValue());

                                long expiryTimeS = Long.parseLong((expiresList.item(0)).getNodeValue());
                                long currentTimeMS = System.currentTimeMillis();

                                editor.putLong("expiryTimeS", expiryTimeS);
                                editor.putLong("currentTimeMS", currentTimeMS);
                                editor.putString("userName", userName);
                                editor.apply();
                            }
                        } catch (Exception e) {
                            Log.e(TAG, "XML Parsing Exception = " + e.toString());
                            return false;
                        }
                        return true;
                    }
                }.execute(request);
            }
        });