Re: radioitem

[muppet <scott asofyet org>]

On Jul 20, 2005, at 4:14 AM, Beast wrote:

> muppet wrote:
>
> > probably belongs in the FAQ:
> > http://mail.gnome.org/archives/gtk-perl-list/2003-September/ 
> > msg00081.html
> > http://mail.gnome.org/archives/gtk-perl-list/2004-April/msg00115.html
> > http://mail.gnome.org/archives/gtk-perl-list/2005-March/msg00039.html
>
> Thanks, but I still have a problem. It trigger action twice on  
> every event, what could be the reason?

It fires once per radio button or radio item that is toggled.  When  
you select a new toggle item, one is made inactive and the other is  
made active; the toggled event fires immediately after each item  
changes state.


> sub radio_callback {
>   my $self = shift;
>   if ($self->{menu}->get_widget('/Radio/Radio One')->get_active) {
>       print "Radio One active\n";
>    }
> }

You're ignoring the widget that is passed in, that is, the widget  
which actually had the event, and unconditionally fetching the one in  
which you're interested.  Therefore it looks like the same event  
fires twice, but really it's two different events that make up the  
same action; the difference is that different items are giving their  
change notifications.

You must do this in your code because you're ignoring all the  
arguments given to the real menu callback:

    callback => sub { $self->radio_callback }.

That is, you're ignoring all arguments and proxying the event to a  
method on your object, which is trapped in the closure (without  
seeing the rest of the code, i don't know whether that's a global or  
lexical or whatever).

That closure is actually passed your user data (likely undef), the  
action id (0, because you didn't specify one), and the reference to  
the menuitem widget on which the event fired.  If you change your  
code to something more like this:

   callback => \&radio_callback,
   ...
   sub radio_callback {
     my ($user_data, $action_id, $menu_item) = @_;
     # this is fired for both the radio item that is being  
deselected and the
     # one that has just been selected.  the one that has been  
selected is
     # now "active".
     if ($menu_item->get_active) {
        print $menu_item->get_child->get_text." activated\n";
        # if you specified a callback_action id, you could also use  
that
        # to decide which item has become active.
     }
  }

You can get $self in radio_callback by using $self as the user data  
in your SimpleMenu object,

    $simplemenu = Gtk2::SimpleMenu->new (
                                  menu_tree => $menu_tree,
                                  user_data => $self,   # so all  
callbacks get $self
    );




--
"There's a documentary that i wanted to watch on PBS.  I heard about  
it in NPR.  ... Oh my god, did i just say that?"
  -- elysse