评估OpenTok开发文本视频聊天App：Xamarin.iOS文本消息接收异常

Hey there, let's work through why your text messages aren't showing up on the other iPhone. I've debugged similar OpenTok signal issues in Xamarin before, so here are the key checks to prioritize:

1. You're Sending Signals to Your Own Connection (Most Likely Culprit) #

Looking at your code:

Session.SignalWithType("signal", message, Session.Connection,true, out err);

The third parameter Session.Connection refers to your local device's connection to the OpenTok session. That means you're sending the signal to yourself, not the other iPhone in the session!

Fix: Target the Remote Connection #

You need to capture the other participant's connection when they join the session, then use that connection to send signals:

// Store the remote participant's connection
private OTConnection _remotePeerConnection;

// Subscribe to the connection event when initializing your session
session.ReceivedConnection += (sender, args) =>
{
    // Ignore your own connection
    if (args.Connection != session.Connection)
    {
        _remotePeerConnection = args.Connection;
        Console.WriteLine("Remote participant connected!");
    }
};

// When sending a message, use the stored remote connection
if (_remotePeerConnection != null)
{
    NSError signalErr;
    bool sendSuccess = session.SignalWithType("signal", message, _remotePeerConnection, true, out signalErr);
    
    if (!sendSuccess)
    {
        Console.WriteLine($"Failed to send signal: {signalErr?.LocalizedDescription}");
    }
}
else
{
    Console.WriteLine("No remote participant to send to!");
}

2. Verify Signal Event Subscription #

Make sure you've properly subscribed to the ReceivedSignalType event before connecting to the session. If you subscribe after connecting, you might miss incoming signals:

// Do this right after initializing your session instance
session.ReceivedSignalType += HandleIncomingSignal;

// Then connect to the session
session.Connect(apiKey, sessionToken);

// Your signal handler method
private void HandleIncomingSignal(object sender, Opentok.Session.ReceivedSignalEventArgs e)
{
    // Check if it's your "signal" type message
    if (e.Type == "signal")
    {
        string incomingMessage = e.Data;
        // Update your UI with the message here
        Console.WriteLine($"Received message: {incomingMessage}");
    }
}

Double-check that you haven't accidentally unsubscribed from this event somewhere in your code.

3. Check for Send Errors #

Always inspect the err output variable after calling SignalWithType. It will tell you if the signal failed to send (e.g., session not connected, message too large):

NSError sendError;
bool didSend = session.SignalWithType("signal", message, targetConnection, true, out sendError);

if (!didSend && sendError != null)
{
    Console.WriteLine($"Signal send failed: {sendError.LocalizedDescription}");
}

Common issues here include:

• Sending signals before the session reaches OTSessionState.Connected
• Message content exceeding OpenTok's 8KB limit for signals

4. Test Broadcast Mode #

To rule out connection targeting issues, try sending a broadcast signal (send to all participants, including yourself) by passing null as the connection parameter:

session.SignalWithType("signal", message, null, true, out err);

If the other iPhone receives this broadcast, the problem is definitely in how you're capturing or using the remote connection. If not, move on to the next check.

5. Confirm Session State & Permissions #

• Ensure your session is in the OTSessionState.Connected state before sending signals. Add a check:

  if (session.State != OTSessionState.Connected)
  {
      Console.WriteLine("Cannot send signal: Session not connected");
      return;
  }
  

• Double-check that your OpenTok project hasn't restricted signal functionality (this is enabled by default, but it's worth verifying in your OpenTok dashboard).

内容的提问来源于stack exchange，提问作者Marius B.