上拉加载的使用问题

                upFetchModule.isUpFetchEnable = true
                upFetchModule.setOnUpFetchListener {
                    viewModel.getHistoryMessages(
                        false,
                        args.userId.toString(),
                        getItemOrNull(0)
                    )
                        .asLiveData().observe(viewLifecycleOwner) {
                            addData(0, it)
                        }
                }

这是我的代码，使用上有几个问题：
1、实现了上拉加载但是实际上并不能上拉，没有任何UI和上拉的提示
2、会自动调用2次 UpFetchListener 中的代码，如何关闭？

Start by reviewing the reported setup around upFetchModule.isUpFetchEnable, setOnUpFetchListener, and getHistoryMessages. Reproduce both symptoms: no visible upward-loading behavior and two calls to UpFetchListener. Done means identifying the missing usage or library behavior and confirming the correction prevents duplicate loading.