[Resolved] QWidget window flag behavior changed in Qt 4.8?

ronM71

I have a certain QWidget derived class.

Look at the window flags i'm giving it. In my app it functions like the drop down component of the combo box:

@setWindowFlags(Qt::FramelessWindowHint | Qt::Popup);@

with Qt 4.7.4, the "FocusOutEvent" is called when I click outside of the widget, even if the click is on the window caption. I use the event to hide my widget. That's the desired behavior I'd like to see. With Qt 4.8 however, "FocusOutEvent" is never called when clicking outside my widget on non-focus receiving elements and/or my window caption, thus, it still sticks around. I can actually drag the window away from my still-visible popup widget...

Something changed in Qt 4.8 something changed. Is there a way around it?

ronM71

None of the conventional techniques work here. No mouse grabbing, no eventFilter. Qt doesn't get any event when i click my OSX window caption. I show my popup, grab my OSX window caption, and drag the window away from the still opened popup. For me, this is a new deal-breaker bug introduced in Qt 4.8. Qt 4.7.4 works well, the popup disappears as soon as I click the window caption. Reluctantly I am forced to revert to 4.7.4. Pity.

ronM71

This really sucks as I have to revert to Qt 4.7.4, missing out on all the bug fixes of Qt 4.8

lgeyer

Have you already filed a bug report?

ronM71

I intend to today.

ronM71

Submitted:

https://bugreports.qt-project.org/browse/QTBUG-24162

lgeyer

Perfectly. Please add a link to this thread to the bug report.

ronM71

added.

goetz

I have a similar use case and I install an eventFilter on the QApplication object - that receives the mouse click. I then check if the click is on my object or any subwidgets of it. If not, I close that widget. That special popup is used with exec(), just like a menu or a dialog. I'll show the implementation of exec() and the eventFilter() here:

@
QChar MySpecialPopup::exec()
{
if( _eventLoop ) {
qWarning("MySpecialPopup::exec: Recursive call detected");
return QChar();
}

_selectedChar = QChar();

bool deleteOnClose = testAttribute(Qt::WA_DeleteOnClose);
setAttribute(Qt::WA_DeleteOnClose, false);

_dialogIsOpen = true;
show();
qApp->setActiveWindow( this );
setFocus();
qApp->installEventFilter( this );
installEventFilter(this);

QEventLoop eventLoop;
_eventLoop = &eventLoop;
QPointer<MySpecialPopup> guard = this;
connect( qApp, SIGNAL(focusChanged(QWidget*,QWidget*)),
         this, SLOT(focusChanged(QWidget*,QWidget*)));

(void) eventLoop.exec&#40;QEventLoop::DialogExec&#41;;

disconnect( qApp, SIGNAL(focusChanged(QWidget*,QWidget*)),
            this, SLOT(focusChanged(QWidget*,QWidget*)));

_dialogIsOpen = false;
removeEventFilter(this);
qApp->removeEventFilter( this );
hide();

if (guard.isNull())
    return QChar();

_eventLoop = 0;
if (deleteOnClose)
    delete this;

return _selectedChar;

}

bool MySpecialPopup::eventFilter(QObject *obj, QEvent *event)
{
if( !_dialogIsOpen )
return MyBaseClassWidget::eventFilter( obj, event );

if(event->type() == QEvent::MouseButtonPress
   && obj != this 
   && !findChildren<QObject *>().contains( obj )
 ) {
    exitEventLoop( QChar() );
    return MyBaseClassWidget::eventFilter( obj, event );
}

#if !defined(Q_WS_MAC)
} else if( event->type() == QEvent::WindowDeactivate ) {
exitEventLoop( QChar() );
return MyBaseClassWidget::eventFilter( obj, event );
#endif

#if !defined(Q_WS_X11)
} else if( event->type() == QEvent::ApplicationDeactivate ) {
exitEventLoop( QChar() );
return MyBaseClassWidget::eventFilter( obj, event );
#endif
}
return MyBaseClassWidget::eventFilter( obj, event );
}
@

ronM71

Volker, you are a mad scientist ;-)
I'll give that a try in the next couple of days.