How to populate comboBox and List from XML!

1 
<root>

 <sport name="soccer">


       <tournament name="Doing league FA Cup"> india-pak  3-2,eng-aus  2-1,zmb-bng  2-2 </tournament>


       <tournament name="Tournament B"> west-new  1-2,holl-kenya  2-3,eng-aus  3-3 </tournament>


       <tournament name="Tournament C"> ind-new  1-2,holl-kenya  2-3,pak-aus  3-3 </tournament>




 </sport>


 <sport name="cricket">


       <tournament name="Doing league FA Cup"> india-pak  3-2,eng-aus  2-1,zmb-bng  2-2 </tournament>


       <tournament name="Tournament B"> west-new  1-2,holl-kenya  2-3,eng-aus  3-3 </tournament>


       <tournament name="Tournament C"> ind-new  1-2,holl-kenya  2-3,pak-aus  3-3 </tournament>




 </sport>


  </root>

and i want to populate my comboBox named sports_cmb with the sports names only there are two in this case, and i want to populate my second comboBox name tournaments_cmb with the tournaments names of the respective sports , and when anyone select one of the tournament the respective team names and there score will be shown in the list component

plz help me out … thanks in advance…