在将元素插入到recyclerview时，如何滚动到底部？

问题描述

我正在练习构建一个聊天应用程序。当我在recyclerview中插入一个项目时，需要将其滚动到底部。我的recyclerview代码现在看起来像这样。我尝试添加一个onScroll侦听器，但是这种方法是错误的。谢谢！

        final linearlayoutmanager linearlayoutmanager = new linearlayoutmanager(getActivity());
        ((SimpleItemAnimator) binding.chatRecyclerView.getItemAnimator()).setSupportsChangeAnimations(false);
        linearlayoutmanager.setReverseLayout(true);
        binding.chatRecyclerView.setLayoutManager(linearlayoutmanager);

        binding.chatRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrolled(@NonNull RecyclerView recyclerView,int dx,int dy) {
                super.onScrolled(recyclerView,dx,dy);
                int firstVisiblePosition = linearlayoutmanager.findLastVisibleItemPosition();
                Log.i(TAG,"onScrolled: " + firstVisiblePosition);
                if (dy < 0) {
                    binding.chatDate.setVisibility(View.VISIBLE);
                    binding.chatDate.setText(sfdMainDate.format(new Date(chatadapter.getItem(firstVisiblePosition).getTimestamp())));
                } else if (dy > 0) {
                    binding.chatDate.setVisibility(View.GONE);
                }
            }
        });```

解决方法

将数据观察器添加到适配器中，并覆盖onItemRangeInserted。

adapter.registerAdapterDataObserver(new RecyclerView.AdapterDataObserver() {
            @Override
            public void onItemRangeInserted(int positionStart,int itemCount) {
                binding.chatRecyclerView.smoothScrollToPosition(0);
            }
        });```