Re: [Fxruby-users] Connecting multiple listeners to an object

[Lyle J. <ly...@kn...>]

On Mar 29, 2004, at 9:06 PM, Daniel Sheppard wrote:

> I've been frustrated with the fact that you can't connect multiple
> things to an FXObject. Ie.
>
> 	target = FXDataTarget.new()
> 	target.connect(SEL_COMMAND) { puts "hello" }
> 	target.connect(SEL_COMMAND) { puts "hello2" }
>
> The only thing that gets printed when the target is changed is 
> "hello2".

Correct. Each object has exactly one message target, and the way that 
the connect() method is implemented is that it creates a target behind 
the scenes.

> How do others normally deal with this? Do you have your code such that
> all connectors must go through in intermediary? Do you only connect in
> the one place?

In a lot of cases, multiple "connections" for a command message (as in 
your example) are used to update the states of different objects based 
on some event. This is a natural choice for, say, Java programmers, who 
are used to Swing's model of having multiple listeners for a given 
event.

FOX's approach to this is very different and emphasizes the use of GUI 
update to update the state of things. So for example instead of 
something like this:

	someButton.connect(SEL_COMMAND) {
		update_the_main_window_title()
		update_the_selected_text_color()
		update_the_button_font_size()
	}

you would instead see code like this:

	main_window.connect(SEL_UPDATE) {
		update_my_title()
	}
	selected_text.connect(SEL_UPDATE) {
		update_my_color()
	}
	button.connect(SEL_UPDATE) {
		update_font_size()
	}

For more about this, see the FOX documentation at:

	http://www.fox-toolkit.org.

> I've thrown together a module to include in classes that I want to
> multi-connect to.

<snip>

Yes, this looks fine too ;)