public class LoginFragment extends Fragment {

private static final String TAG = "LoginFragment";

EditText mUsername, mPassword;
Button mLogin;
String url = "abc";

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.fragment_login, container, false);

    mUsername = (EditText) rootView.findViewById(R.id.login_name_edit_text);
    mPassword = (EditText) rootView.findViewById(R.id.login_password_edit_text);
    mLogin = (Button) rootView.findViewById(R.id.login_button);

    mLogin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            String username = mUsername.toString();
            String password = mPassword.toString();

            if (username.trim().length() > 0 && password.trim().length() > 0) {
                checkLogin(username, password);
            } else {
                Toast.makeText(getContext(), "Please enter the credentials!", Toast.LENGTH_SHORT).show();
            }
        }
    });

    return rootView;
}

private void checkLogin(final String username, final String password) {
    // Tag used to cancel the request

    StringRequest strReq = new StringRequest(Request.Method.POST,
            url, new Response.Listener<String>() {

        @Override
        public void onResponse(String response) {
            Log.d(TAG, "Login Response: " + response.toString());

            try {
                JSONObject jObj = new JSONObject(response);
                boolean error = jObj.getBoolean("error");

                // Check for error node in json
                if (!error) {
                    // user successfully logged in

                    // Launch main activity
                    Intent intent = new Intent(getActivity(),
                            MainActivity.class);
                    startActivity(intent);
                    getActivity().finish();
                } else {
                    // Error in login. Get the error message
                    String errorMsg = jObj.getString("message");
                    Toast.makeText(getContext(),
                            errorMsg, Toast.LENGTH_LONG).show();
                }
            } catch (JSONException e) {
                // JSON error
                e.printStackTrace();
            }

        }
    }, new Response.ErrorListener() {

        @Override
        public void onErrorResponse(VolleyError error) {
            Log.e(TAG, "Login Error: " + error.getMessage());
            Toast.makeText(getContext(),
                    error.getMessage(), Toast.LENGTH_LONG).show();
        }
    }) {

        @Override
        public String getBodyContentType() {
            return "application/x-www-form-urlencoded; charset=UTF-8";
        }

        @Override
        protected Map<String, String> getParams() throws AuthFailureError {
            // Posting parameters to login url
            Map<String, String> params = new HashMap<String, String>();
            params.put("username", username);
            params.put("password", password);

            return params;
        }

    };

    // Adding request to request queue
    MySingleton.getInstance(getContext()).addToRequestQueue(strReq);
}