如何阅读Facebook App Invite的促销代码

Question

以下是从playstore安装后接收promocode的代码

    FacebookSdk.sdkInitialize(getApplicationContext());
    Uri targetUrl = AppLinks.getTargetUrlFromInboundIntent(this, getIntent());
    if (targetUrl != null) 
    {
        Log.i("facebook_app_invite","if");
        Log.i("Activity", "App Link Target URL: " + targetUrl.toString());
    } 
    else 
    {
        AppLinkData.fetchDeferredAppLinkData(getApplicationContext(),new AppLinkData.CompletionHandler() 
        {
            @Override
            public void onDeferredAppLinkDataFetched(AppLinkData appLinkData) 
            {
                 //process applink data
                Log.i("facebook_app_invite","else");
                if (appLinkData != null) 
                {
                    Log.i("facebook_app_invite",appLinkData.getPromotionCode());
                    String promoCode = appLinkData.getPromotionCode();
                    if (promoCode != null)
                    {
                        Log.i("facebook_app_invite",promoCode.toString());
                                // ... execute code related to the promotion ...
                    }
                }
                else
                {
                    System.out.println("appLinkData is null");
                    Log.i("facebook_app_invite", "appLinkData is null");

                }
            }
        });
    }

我使用以下代码发送Facebook应用邀请

try
                {
                    CallbackManager  sCallbackManager = CallbackManager.Factory.create();
                    if (AppInviteDialog.canShow())
                    {
                        AppInviteContent content = new AppInviteContent.Builder()
                                .setApplinkUrl(appLinkUrl)
                                .setPreviewImageUrl(previewImageUrl)
                                .setPromotionDetails("Promotional Message", "promocode").build();
                        AppInviteDialog appInviteDialog = new AppInviteDialog(Ced_SharePage.this);
                        appInviteDialog.registerCallback(sCallbackManager,new FacebookCallback<AppInviteDialog.Result>()
                        {
                            @Override
                            public void onSuccess(AppInviteDialog.Result result)
                            {
                                Log.d("Invitation", "Invitation Sent Successfully");
                                finish();
                            }
                            @Override
                            public void onCancel()
                            {
                                Log.d("Invitation", "Cancel");
                            }
                            @Override
                            public void onError(FacebookException e)
                            {
                                Log.d("Invitation", "Error Occured");
                            }
                        });
                        appInviteDialog.show(content);
                    }
                }
                catch (Exception e)
                {

                }

当我发送Facebook应用邀请时，Facebook应用会显示通知并提示用户安装应用，安装应用后，当我们尝试获取appLinkData时返回null