Re: [paragui-users] Problems with Signals

[Ulf Lorenz]

On Wed, Mar 02, 2005 at 11:04:09PM +0100, Sergio Ruiz wrote:
> Hi!!
> I am getting sick trying to figure out how to use the signals with paragui.
> 
> I have two questions that can save my live (and hopefully many others!!!).
> 
> 1)
> PG_Button* btnquit = app.GetWidget<PG_Button>("btnquit");
> btnquit->sigClick.connect(slot(handle_quit));
> 
> How can I pass arguments to the handle_quit function? Is it possible??
On the fly, I can think of two ways:

1. (crude) Each paragui widget can be given some user data via
   PG_Widget::SetUserData() and some casts. :)
   Maybe this already helps.

2. From the design point of view, you will usually derive e.g. a dialog
   from PG_Window or PG_Widget. If something out of the scope of this
   dialog is to be called, nothing prevents you from defining your own
   signals for the dialog with the correct arguments.

For some more definite answers: What exactly is the situation?

> 2) Inside one class, with no parent class.
> 
> PG_Button* btnquit = app->GetWidget<PG_Button>("btnquit");
> btnquit->sigClick.connect(slot(??,&Widget::handle_quit));
> 
> I dont know to put inside there!. Any solution??
First, AFAIR if you want to connect the signal to a member function of a
class, this class has to derive from SigC::Object, so nothing with "no
parent class". :)

An example may work like this:

class MyDialog : public SigC::Object
{
    MyDialog(PG_Rect rect)
    {
        PG_Button* btn = new PG_Button(0, rect);
        btn->sigClick.connect(slot(*this, &MyDialog::handleClick));
        ...
    }

    ...
    bool handleClick(PG_Button* btn);
    ...
};

So, first parameter has to be the (dereferenced!!) instance of the
class, the second is the address of the function (which BTW has to have
the proper arguments).

> I think it would be a great idea to have a small FAQ in the doc, cause
> with the examples is hard to make a simple nice gui
I have just made a note and will write one in the nearer future. The
paragui autoconf macro needs some patching anyway, so I may even become
active. :)

> Thanks for reading this, and...cool gui!!!!
Quite nice. And you can fix the errors yourself. =8-)


cu,
Ulf

-- 
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