如何使用Firebase适配器设置RecyclerView位置？

Question

很长一段时间以来，我一直试图在recyclerview中使用firebase进行分页。可能这是解决方案。这里我有方法displayAllUserPost（）;它们先在onCreate中运行，然后在recyclerview的底部运行。这是代码。

 private int INITIAL=2;
@Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);displayAllUserStory();

  //Initialize RecyclerView as postList//

        displayAllUserPost();

        postList.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);

                if (!recyclerView.canScrollVertically(1)) {
                    Toast.makeText(MainActivity.this, "Last", Toast.LENGTH_LONG).show();
                    INITIAL=INITIAL+1;
                    displayAllUserPost();

                }
            }
        });

    private void displayAllUserPost()
    {

        Query sortPost=PostRef.limitToLast(INITIAL).orderByChild("counter");
        FirebaseRecyclerOptions<Post> options=new FirebaseRecyclerOptions.Builder<Post>().setQuery(sortPost,Post.class).build();
        FirebaseRecyclerAdapter<Post, PostsViewHolder> firebaseRecyclerAdapter=new FirebaseRecyclerAdapter<Post, PostsViewHolder>(options)
        {
         *//methods implementation//*
        }
        postList.setAdapter(firebaseRecyclerAdapter);
        firebaseRecyclerAdapter.startListening();
    }

但是问题是我如何在当前可见项目上设置recyclerview位置？其自动滚动到第一位置。