从Presence的Type说起
unavailable,
subscribe,
subscribed,
unsubscribe,
unsubscribed,
probe,探测
error;错误
说明:用户添加删除好友是发送Presence包
1.2
SubType
AskType
0:发送订阅好友请求,等待对方接受请求
1:发送取消订阅好友请求
RecvType
Sub(订阅)
remove
none
to
from
both
Ask(是否有发送订阅请求)
""
请求
subscribe
unsubscribe
Rec(是否有接受订阅请求)
""
sub
unsub
http://blog.sina.com.cn/s/blog_6bd8bbe001019fec.html