如何根据片段更改ActionBar项？

public class MyFragment extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_my, container, false);

        // 获取ActionBar对象
        ActionBar actionBar = ((AppCompatActivity) getActivity()).getSupportActionBar();

        // 更改ActionBar的标题
        actionBar.setTitle("My Fragment");

        // 显示返回按钮
        actionBar.setDisplayHomeAsUpEnabled(true);

        return view;
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();

        // 恢复ActionBar的默认状态
        ActionBar actionBar = ((AppCompatActivity) getActivity()).getSupportActionBar();
        actionBar.setTitle(null);
        actionBar.setDisplayHomeAsUpEnabled(false);
    }
}