MCNearbyServiceBrowser 如何知道 MCNearbyServiceAdvertiser 是否拒绝了邀请？

Question

iOS 多人连接问题...

如果 MCNearbyServiceAdvertiser 通过调用拒绝来自 MCNearbyServiceBrowser 的邀请：

invitationHandler(NO, nil);

...在：

advertiser:didReceiveInvitationFromPeer:withContext:invitationHandler:

...有没有办法让MCNearbyServiceBrowser 知道邀请被明确拒绝？

我确实看到当广告商拒绝邀请时，使用MCNearbyServiceBrowser 的设备会收到会话状态更改为MCSessionStateNotConnected，但我想浏览设备也可能由于其他原因收到MCSessionStateNotConnected...比如广告客户的设备消失（关闭等）。

关于如何区分被拒绝的邀请和其他类型的断开连接有什么建议吗？

谢谢。

-艾伦

Answer 1

根据文档，MCSessionStateNotConnected 可以表示

"...附近的对等体拒绝了邀请，连接无法 已建立，或者以前连接的对等方不再连接。”

您没有在问题中说什么会导致邀请被拒绝，但假设它是用户驱动的，一种方法可能是让您的 MCNearbyServiceAdvertiserDelegate 自动接受邀请，为每个同行创建一个新会话，然后向用户展示接受或拒绝连接的选择。在收到表明用户决定的后续消息之前，您的同行不会被视为真正处于会话中：

所以在你的 MCNearbyServiceAdvertiserDelegate 类中你会接受然后提示用户：

- (void)advertiser:(MCNearbyServiceAdvertiser *)advertiser
didReceiveInvitationFromPeer:(MCPeerID *)peerID
                 withContext:(NSData *)context
           invitationHandler:(void(^)(BOOL accept, MCSession *session))invitationHandler {

          //Automatically accept with a new session
          MCSession *newSession = [[MCSession alloc] initWithPeer:_myPeerID];
          newSession.delegate = self;

          //Keep track of the pending sessions in a mutable dictionary
          _pendingSessionPeerIDMap[peerID.displayName] = newSession;

          invitationHandler(YES,newSession);

          /* Code here to present user with option to accept or decline peer */
}

然后当用户响应时，你可以有一个方法发送一个简单的字符串作为包含状态的 NSData：

@property NSData *inviteAcceptedMsgData = [@"MPCInviteYES" dataUsingEncoding:NSUTF8StringEncoding];
@property NSData *inviteDeclinedMsgData = [@"MPCInviteNO" dataUsingEncoding:NSUTF8StringEncoding];

- (void)invitationFromPeerID:(MCPeerID *)peerID receivedResponse:(BOOL)accepted {

   //Send a message to the peer that sent the invitation indicating whether the
   //user accepted or declined

   NSData *msgData = (accepted) ? _inviteAcceptedMsgData : _inviteDeclinedMsgData;

   MCSession *peerSession = _pendingSessionPeerIDMap[peerID.displayName];

   [peerSession sendData:msgData
                 toPeers:@[peerID]
                withMode:MCSessionSendDataReliable
                   error:nil];

    //Remove the pending session
    [_pendingSessionPeerIDMap removeObjectForKey:peerID.displayName];

    //And if the connection was accepted by the user, add to an accepted dictionary
    _acceptedSessionPeerIDMap[peerID.displayName] = peerSession;
}

MCNearbyServiceBrowserDelegate 的工作方式类似：

- (void)browser:(MCNearbyServiceBrowser *)browser 
      foundPeer:(MCPeerID *)peerID 
withDiscoveryInfo:(NSDictionary *)info {

    //Send the invitation with a new session
    MCSession *newSession = [[MCSession alloc] initWithPeer:_myPeerID];
    newSession.delegate = self;

    [browser invitePeer:peerID
              toSession:newSession
            withContext:nil
                timeOut:0];
}

然后浏览器将等待来自它所邀请的对等方的消息以确定邀请是否被真正接受：

- (void)session:(MCSession *)session 
 didReceiveData:(NSData *)data 
       fromPeer:(MCPeerID *)peerID {

       //Check the data to see whether invite was accepted
       if ([data isEqualToData:_inviteAcceptedMsgData]) {

            //Add to an accepted dictionary
            _acceptedSessionPeerIDMap[peerID.displayName] = session;
       }
       else if ([data isEqualToData:_inviteAcceptedMsgData]){

            //Disconnect the session
            [session disconnect];
       }
}

您可能已经有一个消息系统，但这代表了在连接的对等点之间传递状态的简单实现。就发送广播或显示连接的对等点而言，_acceptedSessionPeerIDMap 应作为对等点的真正集合。