Android : how to get notification when facebook friend accept invite to use my app

this is my source code to send the request this code is working properly i want to get response when facebook friends accept invitation to use my app. Thanks in advance Please help me to solve this issue.

private void inviteFacebookFriends(FragmentActivity activity) {
    Bundle params = new Bundle();
    params.putString("message", "Come join me in the Baller Xtreme!!");

    OnCompleteListener onCompleteListener = new OnCompleteListener() {

        @Override
        public void onComplete(Bundle values, FacebookException error) {
            if (error != null) {
                if (error instanceof FacebookOperationCanceledException) {

                    Toast.makeText(getActivity().getApplicationContext(),
                            "Please try again", Toast.LENGTH_SHORT).show();

                } else {
                    Toast.makeText(getActivity().getApplicationContext(),
                            "Network error", Toast.LENGTH_SHORT).show();
                }
            } else {
                String reqId = values.getString("request");



                if (reqId != null) {

                    new Send_request_id(getActivity(), reqId).execute();

                    Toast.makeText(getActivity().getApplicationContext(),
                            reqId, Toast.LENGTH_SHORT).show();
                } else {

                    Toast.makeText(getActivity().getApplicationContext(),
                            "Request cancelled", Toast.LENGTH_SHORT).show();
                }
            }
        }
    };

    (new WebDialog.RequestsDialogBuilder(activity,
            Session.getActiveSession(), params))
            .setOnCompleteListener(onCompleteListener).build().show();
}