1 /*! 2  *  @Author Dylan. 3  * 4  *  Paresence 5  */ 6 typedef void (^userGoOnline) (NSString *); 7 typedef void (^userGoOffline) (NSString *); 8  9 - (void)refreshRosterPResence: (userGoOnline)online10                       offline: (userGoOffline)offline;

 1 #pragma mark presence 2 - (void)refreshRosterPresence: (userGoOnline)online 3                       offline: (userGoOffline)offline { 4      5     self.rosterOnline = online; 6     self.rosterOffline = offline; 7 } 8  9 - (void)xmppStream:(XMPPStream *)sender didReceivePresence:(XMPPPresence *)presence {10     11     // get presence type12     NSString * presenceType = [presence type];13     NSString * userID = [[sender myJID] user];14     15     NSString * presencrFromUser = [[presence from] user];16     if (![presencrFromUser isEqualToString:userID]) {17         if ([presenceType isEqualToString:@"available"]) {18             self.rosterOnline(presencrFromUser);19         } else if ([presenceType isEqualToString:@"unavailable"]) {20             self.rosterOffline(presencrFromUser);21         }22     }23 }

1 /*!2  *  call back block3  */4 @property (nonatomic, copy) userGoOnline rosterOnline;5 @property (nonatomic, copy) userGoOffline rosterOffline;