public class MainActivity extends ActionBarActivity {

    protected EditText username;
    private EditText password;
    protected String enteredUsername;
    private final String serverUrl = "http://192.168.0.103/androidlogin/index.php";

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

        username = (EditText)findViewById(R.id.username_field);
        password = (EditText)findViewById(R.id.password_field);
        Button loginButton = (Button)findViewById(R.id.login);
        Button registerButton = (Button)findViewById(R.id.register_button);

        loginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                enteredUsername = username.getText().toString();
                String enteredPassword = password.getText().toString();

                if(enteredUsername.equals("") || enteredPassword.equals("")){
                    Toast.makeText(MainActivity.this, "Username or password must be filled", Toast.LENGTH_LONG).show();
                    return;
                }
                if(enteredUsername.length() <= 1 || enteredPassword.length() <= 1){
                    Toast.makeText(MainActivity.this, "Username or password length must be greater than one", Toast.LENGTH_LONG).show();
                    return;
                }
                // request authentication with remote server4
                AsyncDataClass asyncRequestObject = new AsyncDataClass();
                asyncRequestObject.execute(serverUrl, enteredUsername, enteredPassword);
            }
        });

        registerButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, RegisterActivity.class);
                startActivity(intent);
            }
        });
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
    private class AsyncDataClass extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... params) {

            HttpParams httpParameters = new BasicHttpParams();
            HttpConnectionParams.setConnectionTimeout(httpParameters, 5000);
            HttpConnectionParams.setSoTimeout(httpParameters, 5000);

            HttpClient httpClient = new DefaultHttpClient(httpParameters);
            HttpPost httpPost = new HttpPost(params[0]);

            String jsonResult = "";
            try {
                List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
                nameValuePairs.add(new BasicNameValuePair("username", params[1]));
                nameValuePairs.add(new BasicNameValuePair("password", params[2]));
                httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

                HttpResponse response = httpClient.execute(httpPost);
                jsonResult = inputStreamToString(response.getEntity().getContent()).toString();

            } catch (ClientProtocolException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return jsonResult;
        }
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }
        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);
            System.out.println("Resulted Value: " + result);
            if(result.equals("") || result == null){
                Toast.makeText(MainActivity.this, "Server connection failed", Toast.LENGTH_LONG).show();
                return;
            }
            int jsonResult = returnParsedJsonObject(result);
            if(jsonResult == 0){
                Toast.makeText(MainActivity.this, "Invalid username or password", Toast.LENGTH_LONG).show();
                return;
            }
            if(jsonResult == 1){
                Intent intent = new Intent(MainActivity.this, LoginActivity.class);
                intent.putExtra("USERNAME", enteredUsername);
                intent.putExtra("MESSAGE", "You have been successfully login");
                startActivity(intent);
            }
        }
        private StringBuilder inputStreamToString(InputStream is) {
            String rLine = "";
            StringBuilder answer = new StringBuilder();
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            try {
                while ((rLine = br.readLine()) != null) {
                    answer.append(rLine);
                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return answer;
        }
    }
    private int returnParsedJsonObject(String result){

        JSONObject resultObject = null;
        int returnedResult = 0;
        try {
            resultObject = new JSONObject(result);
            returnedResult = resultObject.getInt("success");
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return returnedResult;
    }
}