wxruby users - Jul 2005 - comm between gui and app?

To me, the main app (an object) is separate from the app gui (object)...
MVC''ish.

How can I have the gui part communicate to the app that an event has
taken place?  Example code somewhere?

Thank you.

-- 
                            - Martin J. Brown, Jr. -
                            - mjbjr@beaudesign.com -
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mjbjr@beaudesign.com wrote:
> To me, the main app (an object) is separate from the app gui (object)...
> MVC''ish.
> 
> How can I have the gui part communicate to the app that an event has
> taken place?  Example code somewhere?
The short answer to your question as asked would be that you would 
simply invoke normal ruby methods in your app class. Something like this 
(written in email and never run through ruby):

#####################################
class MyApp < Wx::App
...
   def something_happened
     puts("something happened!")
   end
...
end

class MyMainFrame < Wx::Frame
...
   def on_click
     Wx::get_app.something_happened
   end
...
end
#####################################

Hm. That call to get_app.something_happened probably won''t work in 
wxruby 0.6 because it doesn''t have great support for extending 
subclassed classes. Maybe, though. It might not even work in 
wxruby-swig, but I think it would. If not, the alternative to simply 
keep a global $app variable, and invoke $app.something_happened.

In a perfect world, wxruby would support the Wx::Document class, which 
might be a better place for your non-GUI logic. Unfortunately, neither 
wxruby 0.6 nor wxruby-swig supports that yet. However, you could create 
your own document (aka model) class, and create it in your frame 
initializer. In that case, the sample above would end up more like:

def on_click
   @model.something_happened
end


If you wanted to get fancier, you could use the wx event system to pass 
messages to a document or to your app. Your document would be a subclass 
of Wx::EventHandler, which would allow it to receive events. However, 
that''s very much uncharted territory, so if you experiment with it, you
might be the first person on the planet ever to have done so.

Hope that helps.

Kevin

Hi

What sort of GUI events are they, and, importantly, are they things that 
the GUI needs to update in response to the results?

As Kevin suggested, it might be easiest for the GUI to call the app 
object''s methods - the app should expose a set of methods that 
correspond to the actions that can be performed through the GUI

Weft QDA (http://www.pressure.to/qda/) follows this model for gui->app 
communication. app->gui communication - including presenting the results 
of user actions - is handled by a module similar to Observable (in the 
standard library).

When an updateable UI element is created, it subscribes to global app 
events that it is interested in.

class Widget
   include Subscriber
   def initialize(foo, bar)
     ...
     subscribe(:category_added, :category_changed)
   end
   def receive_category_added(category)
     update_myself_to_show_new_category
   end
end

hth
alex

mjbjr@beaudesign.com wrote:
> To me, the main app (an object) is separate from the app gui (object)...
> MVC''ish.
> 
> How can I have the gui part communicate to the app that an event has
> taken place?  Example code somewhere?
> 
> Thank you.
> 
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> wxruby-users mailing list
> wxruby-users@rubyforge.org
> http://rubyforge.org/mailman/listinfo/wxruby-users

Well, I was hoping to not have to sub-class Frame, but that''s what
I''ve
done.  Now, the mainApp object passes ''self'' to the myFrame
object on
instantiation.

-- 
                            - Martin J. Brown, Jr. -
                            - mjbjr@beaudesign.com -
Public PGP Key ID: 0xB09AFEFE keyserver: http://pgpkeys.mit.edu:11371/
Key fingerprint = F3C4 503E 6239 E395 1D33  2FA6 CF11 6F34 B09A FEFE

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