By: thomasb

Eyu, you have made an excellent an astute point. True, callbacks is a 1-to-1 connection between the request originator and the response. If you have a need for multiple callbacks (e.g. more than 1 listener wants to be notified), then use either the ModelLocator databinding approach OR you can create a special dispatcher that supports originators to register for events… think of this an “event bus/pipeline” for your special needs. Unfortunately event bus architectures are ALWAYS specialized and are beyond the scope of a blog. ... See all content Hide content

4 months, 3 weeks ago by thomasb on Wordpress

Databinding is certainly cleaner than callbacks. However, if you have a single view/component instance that wants specific data (without databinding triggers to other instances), then callbacks is probably the cleanest solution. Remember that logic in presentation models works great. Heavy-loading logic in presentation components is not recommended. Instead create facade or delegate classes to manage complexities of multiple view interactions, etc. ... See all content Hide content

4 months, 3 weeks ago by thomasb on Wordpress

Remember that your command MUST call super.execute(event) in order to cache any callbacks to views.

e.g.

override public function execute(event:CairngormEvent):void {

super.execute(event);

switch(event.type) {

…

}

}

AND your response handlers must in turn always invoke a notifyCaller() to notify view or other originating callers that the synch or asynch event has responded/finished.

e.g.

notifyCaller(); ... See all content Hide content

4 months, 3 weeks ago by thomasb on Wordpress

Great article.

This saves the new “notify-view” event generation/dispatch from the command to the view.

Now we have a use case that several views are listening to the “notify-view” event generated by the command. But in your example, it seems only one callback responder can be specified in the original event. Can you suggest a way to resolve our issue?

Thanks!

4 months, 3 weeks ago by eyu on Wordpress

Thanks for writing up this clear explanation. And of course, thanks for clearing up some of the details of using the UM extensions a while back at the Online Flex meetup. It has helped my Flex workflow greatly.

Mani

6 months, 3 weeks ago by diamondTearz on Wordpress

Hey this has helped me a lot. Thank you very much. I’ll be waiting for your “3 Methods for Component Couplings in Flex” article. [:)]

9 months, 3 weeks ago by Prasanta Saha on Wordpress