[Qt-interest] QWizardPage::wizard() overprotected?

[Andreas Pakulat]

On 11.12.08 10:50:27, Niels Dekker - no return address wrote:
> Scott Aron Bloom wrote:
> > Since your deriving from WizardPage anyway.. why not just overload
> > wizard() and make it public?
> 
> Thanks for your reply.  So you say I'd have to override wizard() on all of my 
> derived WizardPage classes, to make it public.  But then why wasn't it public 
> in the first place?  I mean, what does Qt protect me against?
> 
> > That said, why do you need access to the wizard outside of the
> > WizardPage?
> 
> >>From within any of my pages, I need to find my way back to the status bar of 
> my wizard.  Unfortunately, a QWizard cannot have a status bar, so I had to put 
> it onto a QMainWindow.  Anyway, to avoid code duplication, I wrote a single 
> function to get the status bar belonging to my wizard:
> 
>   // Returns the status bar, specific to my application.
>   QStatusBar& getStatusBar(const QWizardPage& page)
>   {
>     // Get the "protected" wizard from the page.
>     const QWizard* const wizard = getWizard(page);
>     assert(wizard != NULL);
> 
>     // My wizard has a QMainWindow as parent.
>     const QMainWindow* const mainWindow =
>       dynamic_cast<const QMainWindow *>(wizard->parent());
>     assert(mainWindow != NULL);
> 
>     QStatusBar* statusBar = mainWindow->statusBar();
>     assert(statusBar != NULL);
>     return *statusBar;
>   }
> 
> 
> Now I can directly get the status bar, from within any of my pages:
>   getStatusBar(*this).showMessage(tr("Status okay!"));
> 
> Doesn't that sound reasonable to you?

Not to me :) First of all, QWizard is a QDialog, embedding it into any
other widget is not a supposed usage of that class.

Why can't the statusbar be part of the page itself? A dialog usually has
the bottom parts for its buttons and the rest is the page of your dialog.
To avoid code-duplication in this case, create a QWizardPage subclass that
simply has a QStatusBar* statusBar() member and a setWidget() function to
set the main widget of the page. Then it just needs to put this widget
into a vertical layout with the statusbar. Thats it, much cleaner with no
hacks involved.

Andreas

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