android - Facebook SDK publish as a separate class

Question

I have created a class with the following method from sample code

private void publishStory() {
        Session session = Session.getActiveSession();
        if (session != null) {

            // Check for publish permissions    
            List<String> permissions = session.getPermissions();
                if (!isSubsetOf(PERMISSIONS, permissions)) {
                    pendingPublishReauthorization = true;
                    Session.NewPermissionsRequest newPermissionsRequest = new Session
                            .NewPermissionsRequest(this, PERMISSIONS);
                    session.requestNewPublishPermissions(newPermissionsRequest);
                    return;
               }

            Bundle postParams = new Bundle();
            postParams.putString("name", "Facebook SDK for Android");
            postParams.putString("caption", "Build great social apps and get more installs.");
            postParams.putString("description", "The Facebook SDK for Android makes it easier and faster to develop Facebook integrated Android apps.");
            postParams.putString("link", "https://developers.facebook.com/android");
            postParams.putString("picture", "https://raw.github.com/fbsamples/ios-3.x-howtos/master/Images/iossdk_logo.png");

            Request.Callback callback= new Request.Callback() {
                public void onCompleted(Response response) {
                    JSONObject graphResponse = response
                                               .getGraphObject()
                                               .getInnerJSONObject();
                    String postId = null;
                    try {
                        postId = graphResponse.getString("id");
                    } catch (JSONException e) {
                        Log.i(TAG,
                            "JSON error "+ e.getMessage());
                    }
                    FacebookRequestError error = response.getError();
                    if (error != null) {
                        Toast.makeText(getActivity()
                             .getApplicationContext(),
                             error.getErrorMessage(),
                             Toast.LENGTH_SHORT).show();
                        } else {
                            Toast.makeText(getActivity()
                                 .getApplicationContext(), 
                                 postId,
                                 Toast.LENGTH_LONG).show();
                    }
                }
            };

            Request request = new Request(session, "me/feed", postParams, 
                                  HttpMethod.POST, callback);

            RequestAsyncTask task = new RequestAsyncTask(request);
            task.execute();
        }
    }

    private boolean isSubsetOf(Collection<String> subset, Collection<String> superset) {
        for (String string : subset) {
            if (!superset.contains(string)) {
                return false;
            }
        }
        return true;
    }

I sometimes get the following error on the permission line-

( session.requestNewPublishPermissions(newPermissionsRequest);)

java.lang.UnsupportedOperationException: Session: an attempt was made to request new permissions for a session that has a pending request.

All I have in this class is the above method. I call it when I want to publish something to Facebook. The code for the Login is in a different class and not called.

Question really is why am I getting this error? Do I need to add some of the UiLifecycleHelper code into the class, and if so, which parts?

Would like to keep this as a seperate class but am I going down the wrong route and should just build into the Activity class that is doing the publish

Thanks for your time