Java Recyclerview使用stackFromEnd动态加载更多数据

嘿，伙计们，我正在使用一个聊天应用程序的回收器视图，它需要有点不同于常规的无限滚动。我想在向上滚动时加载更多数据。我在这里发现了很多东西，但没有什么能帮我解决问题。我使用的是SQLCipher数据库，只想在用户向上滚动时加载更多（旧的）聊天项目

所以我想做的是：

例如，我想加载20个我在这里执行的项目：

ArrayList<Message> getNextMessages(String ChatID, int alreadyLoadedMessages) {
ArrayList<Message> messageList = new ArrayList<>();

String[] args = {ChatID};

Cursor cursor = database.query(MessageDBHelper.DATABASE_NAME,
        columns, MessageDBHelper.COLUMN_USER_ID + "=?", args, null, null, null);

cursor.moveToLast();
int loaded = alreadyLoadedMessages;
while (loaded > 0 && !cursor.isBeforeFirst()) {
    cursor.moveToPrevious();
    loaded--;
}
while (!cursor.isBeforeFirst() && loaded <= LOADED_ITEMS) {
    messageList.add(0, cursorToMassage(cursor));
    cursor.moveToPrevious();
    loaded++;
}
//notify scrollview that we are finished with data loading
Chat.loading = false;
return messageList;
}

ArrayList getNextMessages（字符串ChatID，int-alreadyLoadedMessages）{
ArrayList messageList=新建ArrayList（）；
字符串[]args={ChatID}；
Cursor Cursor=database.query（MessageDBHelper.database_NAME，
列，MessageDBHelper.COLUMN\u USER\u ID+“=？”，args，null，null，null）；
cursor.moveToLast（）；
int loaded=alreadyLoadedMessages；
while（已加载>0&！cursor.isBeforeFirst（））{
cursor.moveToPrevious（）；
加载--；
}
而（！cursor.isBeforeFirst（）&&L
messageArrayList.addAll(messageDataSource.getNextMessages(KontaktNummer, currentLoadedItems));
currentLoadedItems = currentLoadedItems + MessageDataSource.LOADED_ITEMS;
layoutManager = new LinearLayoutManager(this);
layoutManager.setStackFromEnd(true);
recyclerView.setLayoutManager(layoutManager);
final RecyclerView.Adapter adapter = new CustomAdapterChat(this, messageArrayList);
recyclerView.setAdapter(adapter);

recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);
        int visibleItemCount = layoutManager.getChildCount();
        int totalItemCount = layoutManager.getItemCount();
        int pastVisiblesItems = layoutManager.findFirstVisibleItemPosition();
        int sumn = visibleItemCount + pastVisiblesItems;
        if (!loading) {
            if ((visibleItemCount + pastVisiblesItems) < 10) {
                loading = true;
                messageArrayList.addAll(0, messageDataSource.getNextMessages(KontaktNummer, currentLoadedItems));
                currentLoadedItems = currentLoadedItems + MessageDataSource.LOADED_ITEMS;
                //TODO:notify adpater

            }
        }
    }

});