RecyclerView不显示数据库中的数据

// 数据模型类
public class Item {
    private String name;
    // 其他字段...

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

// 适配器类
public class ItemAdapter extends RecyclerView.Adapter<ItemAdapter.ViewHolder> {
    private List<Item> itemList;

    public ItemAdapter(List<Item> itemList) {
        this.itemList = itemList;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_layout, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        Item item = itemList.get(position);
        holder.nameTextView.setText(item.getName());
        // 绑定其他数据...
    }

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

    public class ViewHolder extends RecyclerView.ViewHolder {
        public TextView nameTextView;
        // 其他视图控件...

        public ViewHolder(View itemView) {
            super(itemView);
            nameTextView = itemView.findViewById(R.id.nameTextView);
            // 初始化其他视图控件...
        }
    }
}

// 在Activity或Fragment中使用RecyclerView
public class MainActivity extends AppCompatActivity {
    private RecyclerView recyclerView;
    private ItemAdapter itemAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        recyclerView = findViewById(R.id.recyclerView);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        
        // 从数据库中获取数据
        List<Item> itemList = getDataFromDatabase();
        
        itemAdapter = new ItemAdapter(itemList);
        recyclerView.setAdapter(itemAdapter);
    }

    private List<Item> getDataFromDatabase() {
        // 从数据库中获取数据的逻辑
        // ...
    }
}