滚动后，Recycler移至第一个位置

Question

使用recyclerview和Gridview时遇到困难。问题是当我的应用程序成功加载下一页（下一个数据）时，recyclerview总是回到顶部。

我希望recyclerview从上一个索引开始。

示例：首页加载10项，成功借出下一页后，回收者视图从项目8开始滚动。

要解决该问题，我已经尝试了StackOverflow上的所有解决方案，但仍然一事无成。

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

            if (newState == AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL) {
                isScrolling = true;
            }

        }

        @Override
        public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);

            currentItems = manager.getChildCount();
            totalItems = manager.getItemCount();
            scrolloutItems = manager.findFirstVisibleItemPosition();

            if (isScrolling && (currentItems + scrolloutItems == totalItems)) {
                isScrolling = false;
                getdata(pagetoken);

                //getdata(pagetoken);

                Toast.makeText(MainActivity.this, "Scrolling", Toast.LENGTH_SHORT).show();

            }
        }
    });

}


public void getdata() {
    progress.setVisibility(View.VISIBLE);
    ApiClient.getApis().getblogdata(Constants.key).enqueue(new Callback<MyModel>() {
        @Override
        public void onResponse(Call<MyModel> call, Response<MyModel> response) {
            if (response.isSuccessful()) {
                assert response.body() != null;
                arraylist.addAll(response.body().items);
            }

            if (arraylist != null) {
                adapter = new Data_Adapter(MainActivity.this, arraylist);
                recyclerView.setAdapter(adapter);
            }

            pagetoken = response.body().nextPageToken;

            swiprefresh.setRefreshing(false);
            progress.setVisibility(View.GONE);
        }

        @Override
        public void onFailure(Call<MyModel> call, Throwable t) {
            Toast.makeText(MainActivity.this, "\t \t Connection Error : \n Please Check Your Internet Connection", Toast.LENGTH_SHORT).show();
        }
    });
}

public void getdata(String pageToken) {
    ApiClient.getApis().getblogdata(Constants.key, pageToken).enqueue(new Callback<MyModel>() {
        @Override
        public void onResponse(Call<MyModel> call, Response<MyModel> response) {

            if (response.isSuccessful()) {
                assert response.body() != null;
                arraylist.addAll(response.body().items);
            }

            if (arraylist != null) {
                adapter = new Data_Adapter(MainActivity.this, arraylist);
                recyclerView.setAdapter(adapter);
            }
            if (response.body().nextPageToken != null) {
                pagetoken = response.body().nextPageToken;
            }
            Log.d("retro", "" + arraylist.size());

            swiprefresh.setRefreshing(false);
        }

        @Override
        public void onFailure(Call<MyModel> call, Throwable t) {
            Toast.makeText(MainActivity.this, "Connection Error : \n Please Check Your Internet Connection", Toast.LENGTH_SHORT).show();
        }
    });
}

Answer 1

• 问题：-添加第二页数据后，RecyclerView转到顶部位置

  • 原因：-您一直在制作适配器的新实例

    在这种情况下，适配器是Data_Adapter，而您正在使用

    创建

    adapter = new Data_Adapter(MainActivity.this, arraylist);
    

  • 解决方案：-仅制作一个适配器实例

• 示例：-添加第二页数据后，RecyclerView到达顶部

• 创建数组列表：-

  private ArrayList<String> catList = new ArrayList<>();
  

• 在onCreate [上初始化适配器并将其分配给回收视图]

  if (arraylist != null) {
      adapter = new Data_Adapter(MainActivity.this, arraylist);
      recyclerView.setAdapter(adapter);
  }
  

• 在getdata方法中[在onResponse中以通知适配器]：-

  if (arraylist != null && arraylist.size() > 0) {
      // to notify adapter
      adapter.notifyItemInserted(adapter.getItemCount());
  }