QWidgetWindow as QObject in event filter with Qt5

[Natxo]

Re: QWidgetWindow as QObject in event filter with Qt5

Hello,

I'm opening a new thread following the suggestions of forum's policy, but the issue I have it's the same as in the post i'm replying:

In the migration from Qt4 to Qt5 some code I have to filter events on my application does not work anymore. My software has to filter all events when in "Edition Mode" so only a few widgets/buttons can be available/clickable.

I have a class "InputGrabber" with a QVector of Pointers to QWidget and an eventFilter function. When passing to "Edit" mode , I append the widgets' pointers to the QVector of my InputGrabber that will be available and then, on the eventFilter function the code goes like:

bool InputGrabber::eventFilter (QObject* object, QEvent* anevent)
{
if (QInputEvent* event = dynamic_cast <QInputEvent*> (anevent))
  {
    QWidget* widget = dynamic_cast <QWidget*> (object);
    if (widget)
    {
      if (_widgetList.contains (widget) || _widgetList.contains (widget->parentWidget ()))
        return QObject::eventFilter (object, event);
      else if (QDialog* dlg = dynamic_cast <QDialog*> (widget))
        return QObject::eventFilter (object, event);
      else if (QDialogButtonBox* dlg = dynamic_cast <QDialogButtonBox*> (widget->parentWidget ()))
        return QObject::eventFilter (object, event);
      else
        return true;
    }
    else
      return true;
  }
  else
    return QObject::eventFilter (object, event);
} 
}

The issue migrating to Qt5 is that the
QWidget* widget = dynamic_cast <QWidget*> (object);
cast returns NULL when object inherits from "QWidgetWindow"

Has anyone found same issue and got a solution that follows the same strategy ?? I wouldn't like to change the behaviour of my software , making loops on all widgets and setting setDisabled() for each one...

Thank you very much!

[VRonin]

QWidgetWindow is not a QWidget so you can't cast it.
you could cast it to QWindow but I'm not sure it helps with your current algorithm. You could change _widgetList to `QVector<QObject*> if it doesn't break other parts.

P.S.
When using QObject don't use dynamic_cast but qobject_cast

[Natxo]

@VRonin
Thanks a lot for your return.
In the future I'll be using qobject_cast as suggested, and as QWidgetWindow is a "private" class used in the implementation of Qt, I don't advice people to 'play' with it. As said in its header file:

// This file is not part of the Qt API. It exists purely as an
// implementation detail. This header file may change from version to
// version without notice, or even be removed.

I didn't check your advice of using a QVector of QObject pointers, but I also thought about it. Finally I changed the logic: if the cast of the widget fails, I don't stop the event to propage , but I let it 'live' free:

if (widget)
{
//the code above
}
 else
      return QObject::eventFilter (object, event);

And now it works as espected.