Re: [gtkmm] adding a widget to a container

[cedric <cedric probesys com>]

Thanks for answering me, but it seems i ve simplified to much my problem 
not to have you read too much code :-[
So your answer was perfectly pertinent to my question, but i have 
reformulate it:

i develop a modular application, with plugins (test1, test2..., with 
both .hh and .cc files) each one of them is a different class and they 
all herit from a Plugin class (just a .hh). i have loadplugins files 
(both .hh and .cc files) which herit form Plugin.hh and load the plugins 
and incorporate them into the interface by adding buttons in the 
menubar, adding lines in a functionnalities liststore, and creating one 
toolbar for each module. the toolbar of a given module is displayed only 
when this module is selected in the menubar! in this case, i thought i 
would hide the "current" toolbar, and display the "new" toolbar instead.
so to do this, i ve 2 ptr declared in my Plugin.hh file
   static Gtk::HBox *toolBarModContainer_ptr;
   static Gtk::Toolbar *toolBarModDisplayed_ptr;

i use toolBarModContainer_ptr to add the toolbar of each module to the 
container of my interface where i want to put it (in a HBox so...). this 
ptr is initialised in the loadplugins.cc file, before i add the modules 
elements to my interface. without this ptr, i don t see how to "attach" 
each toolbar to the container. i think it s not a problem to have many 
toolbars added to the HBox (but does it a difference to use "pack_start" 
or "add", considering the fact i display only one toolbar at a time?)

i use toolBarModDisplayed_ptr to know what the "current" toolbar. so 
this ptr points on one of the modules' toolbar.
when i want to change the displayed toolbar, i do this:
   (*toolBarModDisplayed_ptr).hide();        //hide the current toolbar
   toolBarModDisplayed_ptr = &toolbarmod;        //the current toolbar 
is now the toolbar of this module
   (*toolBarModDisplayed_ptr).show();        //display the the current 
toolbar
these instructions are done in a module, after it have been selected in 
the menubar. without this ptr, i don t see how to hide the previous 
displayed toolbar.

so in the class constructor of each of my modules, i put some buttons in 
my toolbar, and then i choose ONE of my modules' toolbar to be the 
current one. my toolbar is declared as "Gtk::Toolbar toolbarmod;" in my 
test1.hh (the testX files are my modules).
   toolBarModContainer_ptr->add(toolbarmod);
when i put this, it provoques a segfault: "in test : undefined symbol 
toolbarmod"...
and this time (not like in my previous question), 
toolBarModContainer_ptr points on existing HBox! i ve tried using 
pack_start, but same result... :-(

i ve tried to manipulate a bit toolBarModContainer_ptr to see if it s 
wrongly initialised, by doing
       (*toolBarModContainer_ptr).hide();
when i select a module in the menubar: it hides correctly the HBox (and 
so the toolbar which is inside). so this pointer is ok, or at least it 
seems to be ok! that s why i don t see the problem!
the toolBarModDisplayed_ptr works also, it can hide the non-module 
default toolbar but since i can t add a module toolbar to the HBox, i 
can t see if the "toolBarModDisplayed_ptr = &toolbarmod;" assigment is 
effective (but it compiles).

i hope this time i ve explained clearlier my problem ;-)
so if you have any idea...
thanks again!

cedric
Ainsley Pereira a écrit :

> On Mon, May 03, 2004 at 04:19:47PM +0200, cedric wrote:
>  
>
> > Gtk::HBox a;    a.add(toolbarmod);
> > //it works, normal
> >    
>
> Yes, you've got an HBox and are using it.
>
>  
>
> > Gtk::HBox *b;    b->add(toolbarmod);
> > // provoques a seg fault !?!?!
> >    
>
> You have a POINTER to an HBox, but no HBox to actually point to, so when
> you try to use it, BANG!
>
>  
>
> > Gtk::HBox *c;    (*c).add(toolbarmod);
> > // provoques a seg fault !?!?!
> >    
>
> As before.
> Try Gtk::HBox *b = new Gtk::HBox; if you really want to allocate the
> HBox on the heap (but wouldn't you rather use a class member?).
> (But remember to use manage() or delete it yourself.)
>
> ~Ainsley
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