RecyclerView一开始只显示一项，然后只显示三项

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/recyclerView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    />

RecyclerView recyclerView = findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setAdapter(new MyAdapter());

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
    private List<String> data;

    public MyAdapter() {
        // 初始化数据列表
        data = new ArrayList<>();
        data.add("Item 1");
        data.add("Item 2");
        data.add("Item 3");
        // ...
    }

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

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        // 绑定数据到ViewHolder
        holder.textView.setText(data.get(position));
    }

    @Override
    public int getItemCount() {
        // 返回数据项数量
        return data.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        TextView textView;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            textView = itemView.findViewById(R.id.textView);
        }
    }
}

<TextView
    android:id="@+id/textView"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="16dp"
    />