如何将项动态添加到ListView的自定义适配器

public class CustomAdapter extends BaseAdapter {
    private List<String> itemList;
    private Context context;

    public CustomAdapter(Context context, List<String> itemList) {
        this.context = context;
        this.itemList = itemList;
    }

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

    @Override
    public Object getItem(int position) {
        return itemList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;

        if (convertView == null) {
            convertView = LayoutInflater.from(context).inflate(R.layout.list_item, parent, false);
            holder = new ViewHolder();
            holder.itemTextView = convertView.findViewById(R.id.item_text_view);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        String item = itemList.get(position);
        holder.itemTextView.setText(item);

        return convertView;
    }

    private static class ViewHolder {
        TextView itemTextView;
    }
}

ListView listView = findViewById(R.id.list_view);
List<String> itemList = new ArrayList<>();
CustomAdapter adapter = new CustomAdapter(this, itemList);
listView.setAdapter(adapter);

itemList.add("新项");
adapter.notifyDataSetChanged();