如果 recyclerview 中没有数据，则隐藏按钮

Question

我创建了一个应用程序，其中我有多个编辑文本和一个带有 recyclerviuew 的按钮和一个设置为 Gone 的按钮。单击按钮将我的所有数据添加到我的 recyclerview 列表中，方法是更改​​我的 recycelr 视图和我的按钮的可见性.在我的自定义适配器中，我正在使用图像视图从位置中删除项目，现在我希望如果它从列表中删除所有数据，那么它应该自动隐藏我的 Button 和 recyclerview。

//Recycler_view 适配器

 public class Myviewholder extends RecyclerView.ViewHolder {
        public TextView  land_Detail, area_detail, s_no1;
        public Button delete;


        public Myviewholder(View view) {
            super(view);

            land_Detail = view.findViewById(R.id.hint31);
            area_detail = view.findViewById(R.id.hint21);
            s_no1 = view.findViewById(R.id.hint11);
            delete = view.findViewById(R.id.hint41);

        }
    }

    public Land_adapters(List<Land_list> land_list, Context context) {
        this.laand_list = land_list;
        this.context = context;
    }


    @NonNull
    @Override
    public Land_adapters.Myviewholder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.land_list, parent, false);

        return new Myviewholder(itemView);
    }

    @Override
    public void onBindViewHolder(@NonNull Myviewholder holder, final int position) {
        final Land_list current_year = laand_list.get(position);

        holder.area_detail.setText("District :" + current_year.getDistrict_name() + "\n" + "Village :" + current_year.getVillage_name());

        holder.s_no1.setText(String.valueOf(position + 1));
        holder.land_Detail.setText("Acre :" + current_year.getAcre() + "\n" + "Kanal :" + current_year.getKanal() + "\n" + "Marla :" + current_year.getMarla());
        holder.delete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Toast.makeText(context, "", Toast.LENGTH_SHORT).show();
                Land_list theRemovedItem = laand_list.get(position);
                // remove your item from data base
                laand_list.remove(position);  // remove the item from list
                notifyItemRemoved(position); // notify the adapter about the removed item

            }
        });
    }


    @Override
    public int getItemCount() {
        return laand_list.size();
    }

//我如何在 mainactivity 类中使​​用我的回收器

   public void final_step() {
        // marla_edit.setError(null);
        recyclerView = findViewById(R.id.recycler_view_last1);


        mAdapter1 = new Land_Adapter(last_Year1);
        recyclerView.setHasFixedSize(true);
        RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(mLayoutManager);
        recyclerView.setAdapter(mAdapter1);


        Land_list last_year1 = new Land_list(land_acre, land_kanal, village_selected1, land_marla, district_selected1, teshil_selected1, block_selected1, block_code, teshil_code1, village_code1, district_code);
        last_Year1.add(last_year1);
        mAdapter1.notifyDataSetChanged();
if (!(last_Year1.size() == 0)) {
    RelativeLayout linearLayout = findViewById(R.id.linear123);


    recyclerView.setVisibility(View.VISIBLE);
    next_button.setVisibility(View.VISIBLE);

}
else
{
    next_button.setVisibility(View.INVISIBLE);

}

// 我只是希望当它在 recycelr 视图中按下删除图像时它应该自动隐藏我的按钮。

Answer 1

您可以使用接口通知片段/活动，列表为空。 适配器如下：

public class CustomAdapter extends RecyclerView.Adapter<CustomViewHolder> {

        AdapterListener listener;

        public void setListener(AdapterListener listener) {
            this.listener = listener;
        }

        ...

        @Override
        public void onBindViewHolder(@NonNull Myviewholder holder, final int position) {
            ...
            holder.delete.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    ...
                    // remove your item from data base
                    laand_list.remove(position);  // remove the item from list
                    notifyItemRemoved(position); // notify the adapter about the removed item
                    if (laand_list.size()==0)
                        listener.onDataListIsEmpty();

                }
            });
        }

        public interface AdapterListener {
            void onDataListIsEmpty();
        }

    }

Activity/Fragment 如下：

class MyActivity extends Activity implements CustomAdapter.AdapterListener {

        CustomAdapter adapter;

        @Override
        protected void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            ...
            adapter = new CustomAdapter();
            adapter.setListener(this);
            ...
        }

        @Override
        public void onDataListIsEmpty() {
            // set visible or gone views 
        }
    }