If an instance of those classes has been created, then it will eval to true, otherwise it will be null, so this should work for that part of the problem:
if(_myinstance) _myInstance.addEventListener(myEvent, myHandler); However, if you're creating "A" after "B", "C", and "D", then you'll want to call the code above from say, a Controller class whenever "A" is created. Once "A" is created, then that's a trigger to add the listeners to the other classes if they exist. Make sense? Jason Merrill Bank of America Global Learning Learning & Performance Solutions Join the Bank of America Flash Platform Community and visit our Instructional Technology Design Blog (inote: these are for Bank of America employees only) -----Original Message----- From: flashcoders-boun...@chattyfig.figleaf.com [mailto:flashcoders-boun...@chattyfig.figleaf.com] On Behalf Of Andrew Sinning Sent: Tuesday, February 23, 2010 10:04 AM To: Flash Coders List Subject: [Flashcoders] accessing event dispatchers in a loosely-coupled,modular design Following the discussion about "root" yesterday, it got me thinking about a constant problem I face. Object-A needs to listen to events coming from objects B, C and D, but only if and when these objects actually exist. There's no guarantee that any of the objects B, C and D will be instantiated before or after A is instantiated. So, what's the proper way for A to add itself as a listener to B, C and D? What I'm currently do is this: The event dispatchers (B, C, D etc) implement a singleton interface. Within the target (A), I set up a Timer event to repeatedly check for instances of the dispatchers. Once a dispatcher is found, the target adds itself as a listener, and a pointer to the dispatcher is created so that the target can later remove itself. I'm not very happy with this design, but it's the best that I've been able to come up with. Thanks! _______________________________________________ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders _______________________________________________ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
