RecycleView中可定制适配器的问题- Android/Java

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {

    private List<String> mData;

    public MyAdapter(List<String> data) {
        this.mData = data;
    }

    @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) {
        holder.textView.setText(mData.get(position));
    }

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

    static class ViewHolder extends RecyclerView.ViewHolder {
        TextView textView;

        ViewHolder(View itemView) {
            super(itemView);
            textView = itemView.findViewById(R.id.text_view);
        }
    }
}

mData.add("New Item");
notifyItemInserted(mData.size() - 1);