MultipeerConnectivity Session management - ios7

Question

I am really stuck at the moment trying to get the grasp of invites in the MultipeerConnectivityFramework.
Right now I have an ipad App acting as the Advertiser and an iphone App acting as Browser.
I have implemented a sharedService for the MultipeerFramework and did the following:
Advertiser
#implementation MultipeerConnectivityService {
MCNearbyServiceAdvertiser *_advertiser;
MCSession *_session;
MCNearbyServiceBrowser *_browser;
}
- (void)automaticAdvertiseWithName:(NSString *)name {
MCPeerID *peerID = [[MCPeerID alloc] initWithDisplayName:name];
_session = [[MCSession alloc] initWithPeer:peerID];
_session.delegate = self;
_advertiser = [[MCNearbyServiceAdvertiser alloc] initWithPeer:peerID discoveryInfo:nil serviceType:kServiceType];
_advertiser.delegate = self;
[_advertiser startAdvertisingPeer];
}
- (void)advertiser:(MCNearbyServiceAdvertiser *)advertiser didReceiveInvitationFromPeer:(MCPeerID *)peerID withContext:(NSData *)context invitationHandler:(void (^)(BOOL, MCSession *))invitationHandler {
invitationHandler([#YES boolValue], _session);
NSLog(#"Invitation accepted");
}
Browser
- (void)automaticBrowsingWithName:(NSString *)name {
MCPeerID *peerID = [[MCPeerID alloc] initWithDisplayName:name];
_browser = [[MCNearbyServiceBrowser alloc] initWithPeer:peerID serviceType:kServiceType];
_browser.delegate = self;
[_browser startBrowsingForPeers];
}
- (void)browser:(MCNearbyServiceBrowser *)browser didNotStartBrowsingForPeers:(NSError *)error {
if ([_delegate respondsToSelector:#selector(browser:didNotStartBrowsingForPeers:)]) {
[_delegate browserDidNotStartBrowsingForPeers];
}
}
- (void)browser:(MCNearbyServiceBrowser *)browser foundPeer:(MCPeerID *)peerID withDiscoveryInfo:(NSDictionary *)info {
[browser invitePeer:peerID toSession:[self getMCSession] withContext:nil timeout:10];
if ([_delegate respondsToSelector:#selector(browser:foundPeer:)]) {
[_delegate browser:browser foundPeer:peerID];
}
}
- (void)browser:(MCNearbyServiceBrowser *)browser lostPeer:(MCPeerID *)peerID {
if ([_delegate respondsToSelector:#selector(browserLostPeer:)]) {
[_delegate browserLostPeer:peerID];
}
}
- (MCSession *) getMCSession {
return _session;
}
But then I am getting as feedback in the console:
-[MCNearbyServiceBrowser invitePeer:toSession:withContext:timeout:] Bad argument session=nil
When I check for the found Advertisers, everything is OK. My advertiser ipad is being found. But how can I manage the invite?
So I don't get it right now... When I send an invitation by the browser, what session do I have to use? On the iPad I set up the session like you can see in the "automaticAdvertiseWithName" method. but on the iphone I don't do this when calling "automaticBrowsingWithName"... Is that the problem? And don't they have to be the same session to successfully connect them? And how can I successfully invite my advertiser ipad to the browser?
I am confused by the notion of creating a new session when one has already been created by the advertiser.
I am actually not sure, if the delegate didReceiveInvitation is adding the peer to the connectedPeers at all.
- (void)automaticAdvertiseWithName:(NSString *)name {
MCPeerID *peerID = [[MCPeerID alloc] initWithDisplayName:name];
self.session = [[MCSession alloc] initWithPeer:peerID];
self.session.delegate = self;
_advertiser = [[MCNearbyServiceAdvertiser alloc] initWithPeer:peerID discoveryInfo:nil serviceType:kServiceType];
_advertiser.delegate = self;
[_advertiser startAdvertisingPeer];
}
- (void)advertiser:(MCNearbyServiceAdvertiser *)advertiser didReceiveInvitationFromPeer:(MCPeerID *)peerID withContext:(NSData *)context invitationHandler:(void (^)(BOOL, MCSession *))invitationHandler {
BOOL accept = YES;
invitationHandler(accept, self.session);
NSLog(#"Invitation accepted: %#", self.session);
}
And when I call the property "connectedPeers" on my session, there are no connected peers at all, even though the delegate found one. Did I make a mistake there?

Answer 1

Your problem is that your session is null at the time you call invitePeer:toSession:withContext:timeout...Anyway you have two options to fix this.
You have two options :
Option 1
- move the peerID creation, session creation and session delegate assignment in a place where its executed at all time. For example in the init code for MultipeerConnectivityService class of if its a UIViewController in the viewDidLoad.
Option 2
- add the following snippet before you call "invitePeer:toSession:withContext:timeout:"
if (!_session) {
MCPeerID *peerID = [[MCPeerID alloc] initWithDisplayName:#"Browser"]; // you can customize the name here
_session = [[MCSession alloc] initWithPeer:peerID];
_session.delegate = self;
}
Hope this helps ...good luck!