Yahoo! Connected TV playback events

Question

I'm trying to subscribe to onTimeIndexChanged mediaplayer event. It works fine, as long as view that I'm subscribing in stays focused. When I press back button, or widgets button, my view gets blurred and it no longer receives events.

Is it possible for this subscription to persist through switching views? Are there widget-wide subscriptions?

I am trying to find out if it is possible to count time of playback client-side.

Answer 1

This was also answered on the Yahoo! Connected TV forums at: http://developer.yahoo.net/forum/?showtopic=7383 Yes, you're on the right track. The media player is a singleton and as such isn't bound to any particular view. You can define a listener that subscribes to it in the widget's global execution context. This way you can still receive and handle events that happen when a view is gc'd, and you can still receive those events.

We put these global subscriptions in init.js so they're centrally-located (best practice).

 
EventHandlers.handlerPlayerEvent.subscribeTo(KONtx.mediaplayer, ['onStateChange', 'onTimeIndexChanged'], EventHandlers);

Then, in Javascript/core/EventHandlers.js:

var EventHandlers = {


    //snipped for brevity;

    handlerPlayerEvent: function(event) {
            switch(event.type) {
                    case 'onStateChange':
                            switch(event.payload.newState) {
                                    case KONtx.mediaplayer.constants.states.PLAY:
                                            if(!this._snippetAdded) {
                                                    KONtx.application.addViewConfig({ id: 'snippet-nowplaying',


viewClass: VideoNowPlayingSnippetView });
                                                        this._snippetAdded = true;
                                                }
                                                break;
                                        case KONtx.mediaplayer.constants.states.UNKNOWN:
                                        case KONtx.mediaplayer.constants.states.ERROR:
                                        case KONtx.mediaplayer.constants.states.STOP:
                                        case KONtx.mediaplayer.constants.states.EOF:
                                                KONtx.application.removeView('snippet-nowplaying');
                                                this._snippetAdded = false;
                                                break;
                                }
                                break;

                    case 'onTimeIndexChanged':
                            //do something interesting;
                            break;
            }
    }


};

I should also add that if you're subscribing to events in a view that it's very important to also unsubscribe from them in the view's hideView listener. This can prevent memory leaks and other undesirable behavior.