Create chatroom with XMPP framework and Ejabberd in iOS - objective-c

Question

Basically I'm trying to create a chatroom with all registered users on my domain using a ejabberd server. So a user can see all other online registered users on that domain when he enters the chatroom.
Until now I've only been able to make all the users 'friends / buddies' visible and deliver a notification when a friend goes online or offline with the help of the XMPP framework:
- (void)xmppStream:(XMPPStream *)sender didReceivePresence:(XMPPPresence *)presence {
// a buddy went offline/online
NSString *presenceType = [presence type]; // online/offline
NSString *myUsername = [[sender myJID] user];
NSString *presenceFromUser = [[presence from] user];
if (![presenceFromUser isEqualToString:myUsername]) {
if ([presenceType isEqualToString:#"available"]) {
[_chatDelegate newBuddyOnline:[NSString stringWithFormat:#"%##%#", presenceFromUser, #"chat.denederlandsewateren.nl"]];
} else if ([presenceType isEqualToString:#"unavailable"]) {
[_chatDelegate buddyWentOffline:[NSString stringWithFormat:#"%##%#", presenceFromUser, #"chat.denederlandsewateren.nl"]];
}
}
}
I'm able to get a list with all online registered users but I don't know how to notify the user when somebody goes online or offline.
- (void)getAllRegisteredUsers {
xmppRosterMemStorage = [[XMPPRosterMemoryStorage alloc] init];
xmppRoster = [[XMPPRoster alloc] initWithRosterStorage:xmppRosterMemStorage
dispatchQueue:dispatch_get_main_queue()];
[xmppRoster addDelegate:self delegateQueue:dispatch_get_main_queue()];
xmppRoster.autoAcceptKnownPresenceSubscriptionRequests = false;
xmppRoster.autoFetchRoster = true;
[xmppRoster activate:xmppStream];
[xmppRoster fetchRoster];
NSError *error = [[NSError alloc] init];
NSXMLElement *query = [[NSXMLElement alloc] initWithXMLString:#"<query xmlns='http://jabber.org/protocol/disco#items' node='all users'/>"
error:&error];
XMPPIQ *iq = [XMPPIQ iqWithType:#"get"
to:[XMPPJID jidWithString:#"chat.denederlandsewateren.nl"]
elementID:[xmppStream generateUUID] child:query];
[xmppStream sendElement:iq];
}
- (BOOL)xmppStream:(XMPPStream *)sender didReceiveIQ:(XMPPIQ *)iq
{
NSXMLElement *queryElement = [iq elementForName: #"query" xmlns:
#"http://jabber.org/protocol/disco#items"];
if (queryElement) {
NSArray *itemElements = [queryElement elementsForName: #"item"];
NSMutableArray *mArray = [[NSMutableArray alloc] init];
for (int i=0; i<[itemElements count]; i++) {
NSString *jid=[[[itemElements objectAtIndex:i] attributeForName:#"jid"] stringValue];
[mArray addObject:jid];
[xmppRoster addUser:[XMPPJID jidWithString:jid] withNickname:[[jid componentsSeparatedByString:#"#"] objectAtIndex:0]];
}
}
How can I create a chatroom where the user can see all online registered users on one domain using a Ejabberd server and the XMPP framework?