[Qt-interest] Question SLOT Macro & messing with the QObject::connect method

[Jefferson Bandeira]

Actually i meant something like :
this->MakeMenu(menu, SLOT(handleMenuItems()), items);
instead of
this->MakeMenu(menu, "handleMenuItems()", items);
Sorry just giving shots in the dark, my Qt is currently recompiling so
there's not much i can do about tests. =/
2010/2/4 kent williams <nkwmailinglists at gmail.com>

> So I think in the end the best way to do this would be something like
> this: Instead of the 'evil hacking' below, I'd change the way the
> string constants were set up.  So my call would be something like
> this:
>
> const char *items[] = { "item 1", "item 2", "item 3", 0 };
> this->MakeMenu(menu,SLOT(handleMenuItem()),items);
>
> On Thu, Feb 4, 2010 at 11:05 AM, kent williams
> <nkwmailinglists at gmail.com> wrote:
> > I wanted to use a private method in my MainWindow class to encapsulate
> > some of the Qt boilerplate with respect to building menus.
> >
> > After fiddling about I ended up with this:
> >
> > // theMenu -- menu to add actions to
> > // theAction -- function to connect to triggered
> > //
> > void
> > BTMainWindow::
> > MakeMenu(QMenu *theMenu,const char *theAction,const char **labels)
> > {
> >  std::string _action("1"); // EVIL HACKING -- fake the SLOT macro
> >  _action += theAction;   //
> >  for(unsigned i = 0; labels[i] != 0; i++)
> >    {
> >    QAction *tempAction = new QAction(tr(labels[i]),this);
> >    theMenu->addAction(tempAction);
> >    connect(tempAction,SIGNAL(triggered()),this,
> >            _action.c_str());
> >    }
> > }
> >
> > Now because I'm a new Qt users, when I looked at the QObject
> > documentation, I originally thought I could just pass in a string
> > literal to QObject::connect to specify the slot.  Turns out that
> > really doesn't work -- I kept getting warnings saying stuff like this:
> >
> > Object::connect: Use the SLOT or SIGNAL macro to connect
> > BTMainWindow::loadTrace()
> >
> > So I went looking in the Qt Headers and found this in qobjectdefs.h:
> > #ifndef QT_NO_DEBUG
> > # define QLOCATION "\0"__FILE__":"QTOSTRING(__LINE__)
> > # define METHOD(a)   qFlagLocation("0"#a QLOCATION)
> > # define SLOT(a)     qFlagLocation("1"#a QLOCATION)
> > # define SIGNAL(a)   qFlagLocation("2"#a QLOCATION)
> > #else
> > # define METHOD(a)   "0"#a
> > # define SLOT(a)     "1"#a
> > # define SIGNAL(a)   "2"#a
> > #endif
> >
> > So in order to fake the SLOT macro, just prepend "1" to your string
> > and pass it to QObject::connect.
> >
> > Now to my way of thinking, this is an evil peeking-behind-the-curtain
> > sort of thing to do -- what if some future version of Qt needs to
> > change the SLOT macro?Any code faking SLOT will stop working.
> >
> > So my question is this: is there a non-evil way to get around SLOT()
> > requiring a string literal instead of a char * variable?
> >
>
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-- 
Jefferson Bandeira
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