plz need get buddypress username function

hi
I hope it’s okay to post here my question.

I want to move buddypress menu (Activity, Profile, ..ext) to sidebar area.
The first idea in my mind is to move it link by link, so that I wrote like that :

<a href="<?php global $current_user; echo home_url() . '/members/' . $current_user->user_login . '/activity/'; ?>">Personal</a>

It is work with me !
But, when user name have dots like “mr.brox” or any username with “.”, wordpress make the user name “mr-brox”, and the last code becomes incorrect …

so, any ideas please.