水平 RecyclerView 中的上一個和下一個按鈕

Question

我正在創建電子商務應用程序，我想問你什么時候單擊下一步按鈕然后 RecyclerView 向右移動並顯示下一個項目，當我單擊上一個按鈕然后 RecyclerView 向左移動並顯示上一個項目時？

RecyclerView 外的上一個和下一個按鈕：

代碼 ：

private RecyclerView rcTopPicks;
private RecyclerView.Adapter adapter;
private LinearLayoutManager layoutManager;
private ImageView previousTopPicks, nextTopPicks;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_home, container, false);

    previousTopPicks = view.findViewById(R.id.btn_left_top_picks);
    nextTopPicks = view.findViewById(R.id.btn_right_top_picks);

    initView(view);
    getTopPicksData();

    return view;
}

private void initViews(View view) {
    rcTopPicks = view.findViewById(R.id.rc_top_picks);
    layoutManager = new LinearLayoutManager(getContext(), LinearLayoutManager.HORIZONTAL, false);
    rcTopPicks.setLayoutManager(layoutManager);
}

private void getTopPicksData() {
    // Code for get JSON
    ....................
    adapter = new TopPicksAdapter(productList);
    rcTopPicks.setAdapter(adapter);

    // This button is not move to left and not showing 2 previous items
    previousTopPicks.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            rcTopPicks.scrollToPosition(adapter.getItemCount() - 1);
        }
    });

    // This button is not move to right and not showing 2 next items
    nextTopPicks.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            rcTopPicks.scrollToPosition(adapter.getItemCount() + 1);
        }
    });
}

問題是當我單擊下一步按鈕時如何向右滾動 recyclerview 的位置？ 以及如何在單擊上一個按鈕時向左滾動 recyclerview 的位置？

Answer 1

嘗試在layoutManager的幫助下滾動到位置，您可以將這樣的內容添加到您的代碼中。

int firstVisible = layoutManager.findFirstVisibleItemPosition() - 1;
int lastVisible = layoutManager.findLastVisibleItemPosition() + 1;

if(lastVisible <= adapter.getItemCount()){
   layoutManager.scrollToPosition(lastVisible);
}

Answer 2

單擊下一個和上一個按鈕，此代碼從當前位置滾動到下一個/上一個視圖。

  binding.btPrevImage.setOnClickListener{
        val  imageCurrentPosition=  (binding.rvAllImage.layoutManager as LinearLayoutManager).findFirstVisibleItemPosition()
        if(imageCurrentPosition>0){
            binding.rvAllImage.smoothScrollToPosition(imageCurrentPosition-1)
        }
    }
 binding.btNextImage.setOnClickListener{
        val  imageCurrentPosition=  (binding.rvAllImage.layoutManager as LinearLayoutManager).findLastVisibleItemPosition()
        if(imageCurrentPosition<productImageAdapter.itemCount-1){
            binding.rvAllImage.smoothScrollToPosition(imageCurrentPosition+1)
        }
    }