CODEWITHSUNDEEP
androidchromecast
Simon Raes
Simon Raes

Reputation: 461

Cast custom channel callback never called

I'm working on an Android app that communicates with a Cast receiver app.

Connecting to the app works (I can see the app appear on the tv), but I'm having difficulties getting the custom channel to work.

In the onCreate of my Activity I get the CastContext and add my SessionManagerLister. 

mCastContext = CastContext.getSharedInstance(this);
mCastContext.getSessionManager().addSessionManagerListener(getSessionManagerListener(), CastSession.class);

getSessionManagerListener() returns the listener where I register my MessageReceivedCallback: 

private SessionManagerListener<CastSession> getSessionManagerListener()
{
    return new SessionManagerListener<CastSession>()
    {
        @Override
        public void onSessionStarted(CastSession castSession, String s)
        {
            try
            {
                castSession.setMessageReceivedCallbacks("urn:x-cast:be.myappname.player.cast.v1", new Cast.MessageReceivedCallback()
                {
                    @Override
                    public void onMessageReceived(CastDevice castDevice, String s, String s1)
                    {
                        System.out.println("never reaches this callback");
                    }
                });
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
        }

        ... other methods omitted ...
    }
}

When I tap the Toolbar cast button I can select a device, which triggers the onSessionStarted in the SessionManagerListener (this also starts the receiver app on the tv). I then add the MessageReceivedCallback, but its callback never gets called.

Inspecting my Cast device in Chrome does show the data I'm expecting to receive, it just never seems to reach my Android code. 

cast_receiver.js:67  [667.202s] [cast.receiver.IpcChannel] IPC message 
[667.202s] [cast.receiver.IpcChannel] IPC message sent: {"namespace":"urn:x-cast:be.myappname.player.cast.v1","senderId":"7c442884-74e6-a388-243c-58b4ab3a4527.3471:com.google.sample.cast.refplayer.tutorial-512","data":"{\"type\":\"login request\"}"}

A colleague is working on the iOS app and that one does receive the callback.

Upvotes: 2

Views: 1171

Answers (3)

iCantC
iCantC

Reputation: 3190

In my case, it was more subtle.

The callback worked absolutely fine when the cast session was initiated for the first time. When the user presses the cast button the receiver is registered for the message callback.

override fun onSessionStarted(castSession: CastSession?, p1: String?) {
                liveViewModel.requestPause()
                castSession?.let {
                    setCastChannelReceiver(it, this@myActivity)
                    loadRemoteMedia(it, buildChromeCastInfo())
                }
            }

fun setCastChannelReceiver(castSession: CastSession?, receiver: CastMessageReceiver) {
        castSession?.let {
            castChannel.addReceiver(receiver, castSession)
            it.setMessageReceivedCallbacks(castChannel.nameSpace, castChannel)
        }
    }

Although when the user use to kill the Activity which initiated the cast session and then after traversing other parts of app use to again visit the Activity, the callback failed to work.

Remember, when the user visits the Activity for the second time, the CastSession is already connected. As a result the onSessionStarted(castSession: CastSession, p1: String) method is never called.

I was under the assumption that once the receiver has been registered for the session, it need not be registered again. But still for some reason the callback never worked.

As a final resort, just to be assured I re-registered the receiver in the OnCreate() of the Activity.

override fun onCreate(out:Bundle){
  ....
  setCastChannelReceiver(castSession, receiver)
  ....
}

fun setCastChannelReceiver(castSession: CastSession?, receiver: CastMessageReceiver) {
        castSession?.let {
            castChannel.addReceiver(receiver, castSession)
            it.setMessageReceivedCallbacks(castChannel.nameSpace, castChannel)
        }
    }

And it worked!!

NOTE: For me, the communication between the Sender(Android App) and Cast Receiver only occurred when the string messages were in JSON format.

Upvotes: 0

LachoTomov
LachoTomov

Reputation: 3708

I had the same problem, this is how I managed to get the message to be sent:

context.sendCustomMessage(namespace, undefined, JSON.stringify({
    "a": "b"
}));

This is the javascript on the receiver side. So you need the "undefined" param and also use JSON.stringify(), otherwise the message gets silently dropped. The undefined means "send to all", but you should probably specify sender-id there.

This is in the v3 API.

Upvotes: 0

milleph
milleph

Reputation: 472

Try the following in onSessionStarted

CastContext cc = CastContext.getSharedInstance(this);
SessionManager sm = cc.getSessionManager();
if (sm != null) {
    CastSession cs = sm.getCurrentCastSession();
    if (cs != null) {
        try {
            MyCastChannel mcc = new MyCastChannel();
            cs.setMessageReceivedCallbacks("urn:x-cast:be.myappname.player.cast.v1",mcc);
        }
        catch (IOException e) {
        }
    }
}

public class MyCastChannel implements Cast.MessageReceivedCallback
{
    @Override
    public void onMessageReceived(CastDevice castDevice, String namespace, String message) 
    {   
        // do your thing   
    }
}

Upvotes: 1

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