如何在fragment中对齐屏幕中心的动作栏标题？

public class MyFragment extends Fragment {

    private Toolbar toolbar;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_layout, container, false);

        toolbar = view.findViewById(R.id.toolbar);
        ((AppCompatActivity) getActivity()).setSupportActionBar(toolbar);

        setHasOptionsMenu(true);

        return view;
    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        inflater.inflate(R.menu.menu_fragment, menu);
        super.onCreateOptionsMenu(menu, inflater);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

        // 处理动作栏菜单项的点击事件
        if (id == R.id.action_item) {
            // 执行相应的操作
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}