android - 在 RecyclerView 上插入新项目

Question

我有一个 REST 服务可以对我的请求进行分页...我需要在我的 recyclerview 上插入 20 个元素并在加载之前保留这 20 个元素。

这是我的请求...

VeiculoRequestHelper.veiculosPaginatedRequest(Request.Method.GET, url, null, new Response.Listener<VeiculoPaginated>() {
        @Override
        public void onResponse(VeiculoPaginated response) {
            AnalyticsTracker.getInstance().sendEvent(AnalyticsEnum.Category.MY_VEHICLE, AnalyticsEnum.Action.CLICK, AnalyticsEnum.Label.SUCCESS);

            isLast = response.isLast();

            ArrayList<Veiculo> veiculoArrayList = new ArrayList<>();
            veiculoArrayList.addAll(response.getContent());

            veiculos = veiculoArrayList;

            mAdapter.addItem(veiculos);

            mRecyclerView.setAdapter(mAdapter);

        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            AnalyticsTracker.getInstance().sendEvent(AnalyticsEnum.Category.MY_VEHICLE, AnalyticsEnum.Action.CLICK, AnalyticsEnum.Label.ERROR);

            Toast.makeText(getActivity(), "Erro ao realizar listagem de veículos.", Toast.LENGTH_LONG).show();
        }
    });

这是我添加新项目的适配器方法...

    public void addItem(ArrayList<Veiculo> veiculosArray) {
    if (veiculos != null) {
        veiculos.clear();
        veiculos.addAll(veiculosArray);
        notifyItemInserted(veiculos.size() - 1);
    } else {
        veiculos = veiculosArray;
    }
    notifyDataSetChanged();
}

我做错了什么？插入了 itens 但没有保留旧的 itens...请帮忙!

Answer 1

旧数据将在addItem(ArrayList<Veiculo> veiculosArray)中被清除:

if (veiculos != null) {
  veiculos.clear(); // here they will be cleared
  veiculos.addAll(veiculosArray);
  notifyItemInserted(veiculos.size() - 1);
}

删除此行以保留旧项目。