Re: [Fxruby-users] implementing connect()

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

On May 12, 2004, at 3:02 PM, Claus Spitzer wrote:

> Greetings! I'm at a loss on how to implement event handlers in my
> classes. I looked at the API references and saw that connect() is
> implemented in Responder2, which led me to believe that I need to
> include it in whichever class needs the connect() method. This did not
> work, as the objects 'selector', 'target', and 'value' were missing.
> I've looked at the class that had those (FXDataTarget) and saw that
> they were accessors, so I added those for my class, and it prevents
> the compiler from throwing an error at me, but it's a crude solution,
> and it doesn't do anything except getting rid of the errors. I'm 99%
> sure that what I'm doing is wrong.

OK, first let's try to pin down what it is that you want to do. You 
want your class to be able to have a message target, i.e. to be able to 
call connect() on that object and provide a block to handle that 
message?

If that's the case, your class needs to provide a "target" accessor 
method that returns a reference to the message target (an FXObject 
instance) for that object. If your class is a subclass of FXWindow or 
FXDataTarget you've already got that. Otherwise, do something like:

	class MyClass < FXObject
		include Responder2
		attr_accessor :target
		def initialize
			@target = nil
		end
	end

You also need to mix-in the Responder2 module to get the connect() 
method, as shown.

Now you should be able to do something like this:

	obj = MyClass.new
	obj.connect(SEL_COMMAND) { puts "hey hey hey" }

And inside your class, when you want to "trigger" that callback, send a 
SEL_COMMAND message to the message target, e.g.

	class MyClass
		def make_it_so
			target.handle(self, MKUINT(0, SEL_COMMAND), nil)
		end
	end

I'm sort of rushing through this, so I may have omitted some details. 
Let me know how it goes and if you have some follow-up questions.

Hope this helps,

Lyle