two simple AsyncTasks that use the updated JSONParser class

http://danielnugent.blogspot.kr/2015/06/updated-jsonparser-with.html

class PostAsync extends AsyncTask<String, String, JSONObject> {

        JSONParser jsonParser = new JSONParser();

        private ProgressDialog pDialog;

        private static final String LOGIN_URL = "http://www.example.com/testPost.php";

        private static final String TAG_SUCCESS = "success";
        private static final String TAG_MESSAGE = "message";


        @Override
        protected void onPreExecute() {
            pDialog = new ProgressDialog(MainActivity.this);
            pDialog.setMessage("Attempting login...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }

        @Override
        protected JSONObject doInBackground(String... args) {

            try {

                HashMap<String, String> params = new HashMap<>();
                params.put("name", args[0]);
                params.put("password", args[1]);

                Log.d("request", "starting");

                JSONObject json = jsonParser.makeHttpRequest(
                        LOGIN_URL, "POST", params);

                if (json != null) {
                    Log.d("JSON result", json.toString());

                    return json;
                }

            } catch (Exception e) {
                e.printStackTrace();
            }

            return null;
        }

        protected void onPostExecute(JSONObject json) {

            int success = 0;
            String message = "";

            if (pDialog != null && pDialog.isShowing()) {
                pDialog.dismiss();
            }

            if (json != null) {
                Toast.makeText(MainActivity.this, json.toString(),
                        Toast.LENGTH_LONG).show();

                try {
                    success = json.getInt(TAG_SUCCESS);
                    message = json.getString(TAG_MESSAGE);
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }

            if (success == 1) {
                Log.d("Success!", message);
            }else{
                Log.d("Failure", message);
            }
        }

    }


    class GetAsync extends AsyncTask<String, String, JSONObject> {

        JSONParser jsonParser = new JSONParser();

        private ProgressDialog pDialog;

        private static final String LOGIN_URL = "http://www.example.com/testGet.php";

        private static final String TAG_SUCCESS = "success";
        private static final String TAG_MESSAGE = "message";

        @Override
        protected void onPreExecute() {
            pDialog = new ProgressDialog(MainActivity.this);
            pDialog.setMessage("Attempting login...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }

        @Override
        protected JSONObject doInBackground(String... args) {

            try {

                HashMap<String, String> params = new HashMap<>();
                params.put("name", args[0]);
                params.put("password", args[1]);

                Log.d("request", "starting");

                JSONObject json = jsonParser.makeHttpRequest(
                        LOGIN_URL, "GET", params);

                if (json != null) {
                    Log.d("JSON result", json.toString());

                    return json;
                }

            } catch (Exception e) {
                e.printStackTrace();
            }

            return null;
        }

        protected void onPostExecute(JSONObject json) {

            int success = 0;
            String message = "";

            if (pDialog != null && pDialog.isShowing()) {
                pDialog.dismiss();
            }

            if (json != null) {
                Toast.makeText(MainActivity.this, json.toString(),
                        Toast.LENGTH_LONG).show();

                try {
                    success = json.getInt(TAG_SUCCESS);
                    message = json.getString(TAG_MESSAGE);
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }

            if (success == 1) {
                Log.d("Success!", message);
            }else{
                Log.d("Failure", message);
            }
        }

    }

Here are examples of how you would execute the AsyncTasks in this example:

POST version:

        String username = "testuser";
        String password = "testpass";
        new PostAsync().execute(username, password);

GET version:

        String username = "testuser";
        String password = "testpass";
        new GetAsync().execute(username, password);

Here are the simple PHP pages I used for testing the updated JSONParser class and the AsyncTasks.

Note that in order to actually test the login credentials, database calls would need to be added.

POST method version:

<?php

  // array for JSON response
$response = array();

// check for required fields
if (isset($_POST['name']) && isset($_POST['password'])) {
  
    $name = $_POST['name'];
    $message = $_POST['message'];

    $response["success"] = 1;
    $response["message"] = "Login successful.";

    // echoing JSON response
    print(json_encode($response));
    
  
 } else {
    // required field is missing
    $response["success"] = 0;
    $response["message"] = "Required field(s) missing";

    // echoing JSON response
    print(json_encode($response));
}
?> 

GET method version:

<?php

  // array for JSON response
$response = array();

// check for required fields
if (isset($_GET['name']) && isset($_GET['password'])) {
  
    $name = $_GET['name'];
    $message = $_GET['message'];

    $response["success"] = 1;
    $response["message"] = "Login successful.";

    // echoing JSON response
    print(json_encode($response));
    
  
 } else {
    // required field is missing
    $response["success"] = 0;
    $response["message"] = "Required field(s) missing";

    // echoing JSON response
    print(json_encode($response));
}
?>