Qt-interest Archive, May 2008
Extending QWhatsThis
Message 1 in thread
Hello all,
I'm porting Qt3 code to Qt4 and I'm stucked in a problem with QWhatsThis.
My legacy code extends QWhatsThis this way:
class HelpWhatsThis : public QWhatsThis {
public:
HelpWhatsThis(QWidget * parent, QGAppDialogMediator * med) :
QWhatsThis(parent), _med(med);
// This overloaded method allows the user to request a more
// extended help on the parameter. Clicking on an hyperlink in
// the help message will notify the mediator that further help has
// been requested. The target of the hyperlink is passed to the
// mediator that will update the dialog accordingly.
bool clicked(const QString& href);
private:
QGAppDialogMediator * _med;
Since QWhatsThis has his constructor private in Qt4, I'm unable to keep
the extended class.
My only ideia is to forget this extension creating a ordinary
QWhatsThis and a QAction that will deal with the communication my former
extended class do.
By the way, it is a Mediator Pattern implementation.
Thanks in advance,
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Message 2 in thread
Hi,
"Vitor Vasconcelos Araujo Silva" <Vitor.Vasconcelos@xxxxxxxx> wrote in
message news:483AC35B.1000404@xxxxxxxxxxx
> Hello all,
>
> I'm porting Qt3 code to Qt4 and I'm stucked in a problem with QWhatsThis.
> My legacy code extends QWhatsThis this way:
>
> class HelpWhatsThis : public QWhatsThis {
> public:
>
> HelpWhatsThis(QWidget * parent, QGAppDialogMediator * med) :
> QWhatsThis(parent), _med(med);
>
> // This overloaded method allows the user to request a more
> // extended help on the parameter. Clicking on an hyperlink in
> // the help message will notify the mediator that further help has
> // been requested. The target of the hyperlink is passed to the
> // mediator that will update the dialog accordingly.
> bool clicked(const QString& href);
>
> private:
> QGAppDialogMediator * _med;
>
> Since QWhatsThis has his constructor private in Qt4, I'm unable to keep
> the extended class.
>
> My only ideia is to forget this extension creating a ordinary QWhatsThis
> and a QAction that will deal with the communication my former extended
> class do.
>
> By the way, it is a Mediator Pattern implementation.
You could also look into using the event filter system that is available in
Qt. Since clicking on a hyperlink in a what's this will result in an
QWhatsThisClickedEvent on the widget the what's this is created on, you
should be able to filter those events and handle them in your Mediator
object as usual. I think I would just iterate over the child widgets of your
dialog after construction to install the event filter, but that depends on
how your application is build exactly.
André
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