You used to be able to do this with the Facebook Query Language (FQL) that Facebook exposed, sending something like this query to the FQL endpoint.

   SELECT uid, name, online_presence
   FROM user
   WHERE online_presence IN ('active', 'idle')
   AND uid IN (
     SELECT uid2 FROM friend WHERE uid1 = me()
   )

Unfortunately, the current version of the Facebook Graph API[0] doesn't have the online_presence field, so this is no longer possible. Maybe the Graph API will be updated in the future to also return the online_presence fields?

[0] https://developers.facebook.com/docs/graph-api/reference/v2....