Facebook邀请 - 很少有人在几小时后收到邀请

Question

我在android中完成了“使用facebook邀请用户访问应用程序”的任务，如果我发送邀请，则使用以下代码，邀请消息很少在几小时后发送，否则无法交付，有人知道解决方案吗？

final ImageView facebook1 = (ImageView) findViewById(R.id.facebook1);
        facebook1.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v){


            Facebook mFacebook = new Facebook( APP_ID );

            Bundle params = new Bundle();

            params.putString("message", "Prova ");
            mFacebook.dialog(Singlemenuitem.this, "apprequests", params, new DialogListener() {
                            public void onComplete(Bundle values) {
                                                Toast toast = Toast.makeText(getApplicationContext(), "Done",
                                                        Toast.LENGTH_SHORT);
                                                toast.show();
                                            }

                                            public void onFacebookError(FacebookError error) {
                                                Toast.makeText(getApplicationContext(), "Facebook Error: " + error.getMessage(),
                                                        Toast.LENGTH_SHORT).show();
                                            }

                                            public void onCancel() {
                                                Toast toast = Toast.makeText(getApplicationContext(), "App request cancelled",
                                                        Toast.LENGTH_SHORT);
                                                toast.show();
                                            }

                                            public void onError(DialogError e) {
                                                // TODO Auto-generated method stub

                                            }
                                        });
              } });