Date: Wed, 12 Jun 2002 13:41:48 +0200
From: Johann Spies <jspies at sun.ac.za>
To: lablgtk at kaba.or.jp
Subject: Re: Catching a signal from combo field
Message-ID: <20020612114148.GG30062 at adept.co.za>
Mail-Followup-To: Johann Spies <jspies at sun.ac.za>, lablgtk at kaba.or.jp
References: <20020611151951.GA23882 at adept.co.za> <20020612092458A.garrigue at kurims.kyoto-u.ac.jp>
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In-Reply-To: <20020612092458A.garrigue at kurims.kyoto-u.ac.jp>
Sender: Johann Spies <js at bywoner.sun.ac.za>

Hello Jaques,

Thanks for your answer.  It helped me to understand a little bit
better, but I am still stuck.

> I am not sure of what you are trying to do, in particular your mail
> does not include the code you are compiling.

I am using glade in combination with mlglade which produces three
files: 

gtknw_glade_callbacks.ml
gtknw_glade_interface.ml
gtknw_glade_main.ml

In  *main.ml I have the opportunity to define reaction on callbacks
which will override the callbacks in gtknw_glade_callbacks.ml:

inherit Gtknw_glade_callbacks.default_callbacks


Glade shows two widgets for the combo-field: combo1 and server (the
entry-field).  And in Glade I can select a signal which will be used
in the callback process.  After your mail I select the "changed"
callback in glade from the "server" widget.  

It seems that either there is a bug in mlglade (because I don't see
the callback mentioned somewhere in the three files although it is
defined in the gtknw.glade file) or I am not understanding the process
properly.  It seems that my callback method (the snippet I posted
previously) is not used at all.

> However here is some way to track changes on a combo box:

I am not sure where in this in the code.
> 
> # let w = GWindow.window ~show:true ();;
> val w : GWindow.window = <obj>
> # let c = GEdit.combo ~popdown_strings:["A";"B";"C"] ~packing:w#add ();;
> val c : GEdit.combo = <obj>
> # c#entry#connect#changed (fun () -> prerr_endline c#entry#text);;
> - : GtkSignal.id = <abstr>
> 
> By the way, this is precisely because using box signals on a combobox
> is meaningless that the lablgtk combobox is not a box.

At the moment my "callback" looks like this but the print_string-line
never gets executed so the signal is either not registered with the
correct widget or I don't understand at all what is going on. 

I might try to work without glade, but I could so far not find a
proper tutorial on Lablgtk. The Glade - mlglade combination at least
provide me with a platform to work from and do something useful while
I try and figure out what is going on in the code.

Regards.
Johann

-- 
Johann Spies          Telefoon: 021-808 4036
Informasietegnologie, Universiteit van Stellenbosch

     "And he said unto Jesus, Lord, remember me when thou 
      comest into thy kingdom. And Jesus said unto him, 
      Verily I say unto thee, To day shalt thou be with me 
      in paradise."       Luke 23:42,43