private void userLogin() {
    username = usernameField.getText().toString().trim();
    password = passwordField.getText().toString().trim();

    RequestQueue queue = Volley.newRequestQueue(this);

  // Request a string response from the provided URL.
    StringRequest stringRequest = new StringRequest(Request.Method.GET, LOGIN_URL,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    Toast toast = Toast.makeText(getApplicationContext(), (response), Toast.LENGTH_SHORT);
                    toast.show();
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            Toast toast = Toast.makeText(getApplicationContext(), "Anything doesn't work!", Toast.LENGTH_SHORT);
            toast.show();
        }
    });
 // Add the request to the RequestQueue.
    queue.add(stringRequest);
}