Re: Binding Variables to Widgets

[Emmanuele Bassi <ebassi gmail com>]

On Wed, 2007-01-03 at 23:12 -0600, Nik Ogura wrote:
> Forgive my noobishness, I'm coming from a Perl/Tk background.  
>
> In Perl/Tk you can easily bind a variable to a widget, so that any
> changes to the widget text are automatically changed in the bound
> variable.
>
> Is this sort of thing possible in Gtk2-perl?  Or am I stuck doing
> $widget->set_text and $widget->get_text calls to do the same?

you want Glib::Object::tie_preferences:

  $object->tie_properties ($all=FALSE)

        * $all (boolean) if FALSE (or omitted) tie only properties for this
        objectâs class, if TRUE tie the properties of this and all parent
        classes.

        A special method avaiable to Glib::Object derivatives, it uses
        perlâs tie facilities to associate hash keys with the properties of
        the object. For example:
        
          $button->tie_properties;
          # equivalent to $button->set (label => âHello Worldâ);
          $button->{label} = âHello Worldâ;
          print "the label is: ".$button->{label}."\n";

        [...]
                -- from Glib::Object perldoc page

obviously, you really want to be sure that you don't end up adding a key
named 'text' to your Gtk2::Entry object, or you'd end up with a nasty
loop.

in any case, if you want to update a variable in sync with the changes,
just attach a callback to the Gtk2::Entry 'changed' signal and update
the variable there: it's called 'event-driven programming' for a reason,
you know. ;-)

ciao,
 Emmanuele.

-- 
Emmanuele Bassi,  E: ebassi gmail com
W: http://www.emmanuelebassi.net
B: http://log.emmanuelebassi.net