无尽的RecyclerView：只加载一次数据

Question

从早上搜索此错误但没有任何效果。问题是我已经实现了Endless recyclerview，它从网站的不同页面获取JSON数据，但这仅适用于第二页之后的第二页，它不会提取任何数据。

参见onLoadMore函数：

adapter.setLoadMore(new ILoadMore() {
                    @Override
                    public void loadMore() {
                        if (postItems.size() <= count) {
                            postItems.add(null);
                            adapter.notifyItemInserted(postItems.size() - 1);
                            new Handler().postDelayed(new Runnable() {
                                @Override
                                public void run() {
                                    postItems.remove(postItems.size() - 1);

                                    counter += 1;
                                    Log.d("HAHAHAHA", "onScrolled: End " + counter);
                                    if (counter <= pages) {
                                        Log.d("HAHAHAHA", "onScrolled: Counter: " + counter);
                                        getData(counter);
                                        //Toast.makeText(getContext(), "Loading More", Toast.LENGTH_SHORT).show();
                                    }
                                }
                            }, 2000);
                            adapter.setLoaded();
                        } else {
                            Toast.makeText(getContext(), "Done", Toast.LENGTH_SHORT).show();
                        }
                    }
                });

            } catch (JSONException e) {
                e.printStackTrace();
            }

适配器代码：

public AllAdapter(RecyclerView recyclerView, Activity activity, List<PostItem> postItemList, Controller controller) {
    this.activity = activity;
    this.postItemList = postItemList;
    this.controller = controller;

    final LinearLayoutManager manager = (LinearLayoutManager) recyclerView.getLayoutManager();

    recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);

            totalItemCount = manager.getItemCount();
            lastVisibleItem = manager.findLastVisibleItemPosition();

            if(!isLoading && totalItemCount <= (lastVisibleItem + visibleThreshold)) {
                Log.d("HAHAHAHA", "onScrolled: End");
                Log.d("HAHAHAHA", "onScrolled: End" + loadMore);
                if (loadMore != null)
                    Log.d("HAHAHAHA", "Inside if");
                    loadMore.loadMore();
                isLoading = true;
            }
        }
    });
}

@Override
public int getItemViewType(int position) {
    return postItemList.get(position) == null? VIEW_TYPE_LOAD: VIEW_TYPE_ITEM;

}

public void setLoadMore(ILoadMore loading) {
    Log.d("HAHAHAHA", "onScrolled: End Inside setLoadMore");
    this.loadMore = loading;
}

public void setLoaded() {
    Log.d("HAHAHAHA", "onScrolled: End" + "Inside SetLoaded");
    isLoading = false;
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    if (viewType == VIEW_TYPE_ITEM) {
        return new ItemViewHolder(LayoutInflater.from(activity)
                .inflate(R.layout.allpost_item, parent, false));
    }
    else if (viewType == VIEW_TYPE_LOAD) {
        return new LoadingViewHolder(LayoutInflater.from(parent.getContext())
                .inflate(R.layout.progressbar, parent, false));

    }
    return null;
}

@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
    if (holder instanceof ItemViewHolder) {

        ItemViewHolder itemViewHolder = (ItemViewHolder) holder;
        Typeface face = Typeface.createFromAsset(activity.getAssets(), "googlesans.ttf");
        PostItem postItem = postItemList.get(position);
        itemViewHolder.all_title.setText(Html.fromHtml(postItem.getTitle().toString()));
        itemViewHolder.date.setText(Html.fromHtml(postItem.getDate().toString()));
        itemViewHolder.category.setText(Html.fromHtml(postItem.getCategory().toString()));

        itemViewHolder.all_title.setTypeface(face);
        Glide.with(activity).load(postItem.getThumbnail()).into(itemViewHolder.thumbnail);
    } else if (holder instanceof LoadingViewHolder) {
        LoadingViewHolder loadingViewHolder = (LoadingViewHolder) holder;
        loadingViewHolder.progressBar.setIndeterminate(true);
    }
}

@Override
public int getItemCount() {
    return postItemList.size();
}

当我尝试调试代码时，adapter.setLoadMore（）方法只被调用一次，即之后的第二页甚至不调用它。任何人都可以帮助我吗？