使用RTCDataChannel在iOS上发送消息失败

Question

我设法在A和B之间共享了视频和音频，我发现RTCDataChannelState已经变成了kRTCDataChannelStateOpen。

- (void)channelDidChangeState:(RTCDataChannel*)channel

sendData也可以返回YES，但是我无法接收消息

- (void)peerConnection:(RTCPeerConnection*)peerConnection
    didOpenDataChannel:(RTCDataChannel*)dataChannel

永远不要打电话给我，我认为它应该在冰状态改变为RTCICEConnectionConnected之后调用，但是它没有！

创建数据通道：

RTCDataChannelInit *DataChannelInit = [[RTCDataChannelInit alloc] init];
    DataChannelInit.maxRetransmits = 0;
    DataChannelInit.isOrdered=false;
    DataChannelInit.maxRetransmitTimeMs = -1;
    DataChannelInit.isNegotiated = false;
    DataChannelInit.streamId = 25;
    RTCDataChannel *dataChannel =[_peerConnection createDataChannelWithLabel:@"commands" config:DataChannelInit];
    dataChannel.delegate=self;
    self.datachannel = dataChannel;

我的提议和建议：

- (RTCMediaConstraints *)defaultOfferConstraints {
  NSArray *mandatoryConstraints = @[
      [[RTCPair alloc] initWithKey:@"OfferToReceiveAudio" value:@"true"],
      [[RTCPair alloc] initWithKey:@"OfferToReceiveVideo" value:@"true"]
  ];

    NSArray *optionalConstraints = @[
                                      [[RTCPair alloc] initWithKey:@"internalSctpDataChannels" value:@"true"],
                                      [[RTCPair alloc] initWithKey:@"DtlsSrtpKeyAgreement" value:@"true"]
                                      ];
  RTCMediaConstraints *constraints =
      [[RTCMediaConstraints alloc]
          initWithMandatoryConstraints:mandatoryConstraints
                   optionalConstraints:optionalConstraints];
  return constraints;
}

Answer 1

如果您附加了SDP和WebRTC框架版本，这将更容易发现问题。

如果正确添加数据通道，则在设置RemoteDescription后，以下委托应在接收方调用

-(void)peerConnection:(RTCPeerConnection *)peerConnection
   didOpenDataChannel:(RTCDataChannel *)dataChannel {
     NSLog(@"Received remote data channel %ld ", (long)dataChannel.readyState);
     dc = dataChannel;
     dc.delegate = self;
}

您应该在创建数据通道后创建该报价，以便该报价将包含数据通道的详细信息。 不需要在接收端创建数据信道，因为数据信道是全双工的。