在将元素插入到 recyclerview 时，如何滚动到底部？

Question

我正在练习构建一个聊天应用程序。当我将一个项目插入 recyclerview 时，我需要它滚动到底部。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);
                }
            }
        });```

Answer 1

将数据观察器添加到您的适配器并覆盖 onItemRangeInserted。

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

在将元素插入到 recyclerview 时，如何滚动到底部？

On insertion of an element to recyclerview, how to scroll to the bottom?

android

adapter

android-recyclerview