如何在 recyclerView.setAdapter 中保留新数据

Question

在 TabHost 中，我有 2 个选项卡（2 个片段）。在 tab1 的 onCreateView 中，我有 recycleView.setAdapter。当我单击时，它会加载新数据，然后如果从 tab1 切换到 tab2 然后返回到 tab1，recycleView.setAdapter 会重新加载旧数据。
从 tab2 切换到 tab1 时，如何在 recycleView 中保留新数据？

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {

    // Inflate the layout for this fragment
    View view = inflater.inflate(R.layout.fragment_position, container, false);

    recyclerViewPosition = view.findViewById(R.id.recyclview);
    LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
    recyclerViewPosition.setLayoutManager(linearLayoutManager);
    recyclerViewPosition.setHasFixedSize(true);
    recyclerViewPosition.setAdapter(positionAdapter);

    // searchView
    searchView = view.findViewById(R.id.sview);
    searchView.setOnQueryTextListener(new OnQueryTextListener() {
        @Override
        public boolean onQueryTextSubmit(String query) {
            return false;
        }

        @Override
        public boolean onQueryTextChange(String newText) {
            final List<DataPosition> filteredModelList = filter(mPositionList, newText);
            positionAdapter.setFilter(filteredModelList);
            return true;
        }
    });

    Call<Position> call = mApiService.getPositionList(strTokent);
    call.enqueue(new Callback<Position>() {
        @Override
        public void onResponse(Call<Position> call, Response<Position> response) {
            if (response.isSuccessful()) {

                itemArrayList = response.body().getData().getItems();

                mPositionList.clear();
                dataPosition.clear();

                /* put id and name to hashMap*/
                for (int i = 0; i < itemArrayList.size(); i++) {
                    hashMap.put(itemArrayList.get(i).getName(), itemArrayList.get(i).getId());
                }

                for (int j = 0; j < itemArrayList.size(); j++) {
                    dataPosition.add(itemArrayList.get(j).getName());
                }

                for (String strPosition : dataPosition) {

                    mPositionList.add(new DataPosition(strPosition));
                }
            }
        }

        @Override
        public void onFailure(Call<Position> call, Throwable t) {

        }
    });

    return view;
} 

Answer 1

清除此数组列表：

@Override
public void onResponse(Call<Position> call, Response<Position> response) {
    itemArrayList.clear();
    if (response.isSuccessful()) {

        itemArrayList = response.body().getData().getItems();

        mPositionList.clear();
        dataPosition.clear();
    }
}