QWidget::windowRole() use as storage for small textual data

Please_Help_me_D

Hi,

In my application I need to distinguish two types of windows:
a) those who displays some data (graphs)
b) other windows
To do this I thinking about to set QWidget::setWindowRole() like:

window1->setWindowRole("display data");
window2->setWindowRole("not display data"):

In documentation it is said that it only makes sense with X11 window system (I haven't ever used it). Is it because this windowRole() text appears somewhere on the window so the user can see this textual data?
Is there a nicer way to distinguish these two types of windows in my case?

SGaist

Hi,

You can use a dynamic property.

Please_Help_me_D

@SGaist thank you! I think this is what I was looking for :)

Please_Help_me_D

@SGaist I'm trying to use bool QObject::setProperty(const char *name, const QVariant &value)
In my MainWindow I call MyClass where I create some objects and set for each of them property:

MyClass::BlaBla(){
    ads::CDockWidget* dockWidget = new ads::CDockWidget("2D Window");
    dockWidget->setWidget(qvtkOpenGLStereoWidget);
    dockWidget->setProperty("IsVisualization", true);
    dockManager->addDockWidget(ads::RightDockWidgetArea, dockWidget);
}

If I write QVariant variant = dockWidget->property("IsVisualization"); then the variant contains correct data everything if ok at this step.
But if I do the same in the MainWindow inside onFocusChanged method I get invalid QVariant:

void MainWindow::onFocusChanged(QWidget* old, QWidget* now){
    if (old != nullptr){
        QVariant variantOLD = old->property("IsVisualization");
    }
    if (now != nullptr){
        QVariant variantNOW = now->property("IsVisualization");
    }
}

What is wrong?

P.S. dockManager and dockWidget are from advanced_docking_system library

JonB

@Please_Help_me_D
Since being inside onFocusChanged() makes no difference to whether you can read a property or not, I can only conclude that neither old nor now are the dockWidget on which you previously set the property, or you have reset it since then.

Did you even try object_cast<>ing old/now to verify they are ads::CDockWidget*?

Please_Help_me_D

@JonB after you wrote I tried it... Yes you are right, they are not a ads::CDockWidget*
I guess I should be able to get ads::CDockWidget* from old/now via old->children?

JonB

@Please_Help_me_D
I was doing this just today. The focus can be hitting some sub widget on a container. In my case widgets on a QMdiSubWindow. To find that I go up via parentWidget() till I find one or hit the topmost. If you are same thing you will want to go up parents from old/now, not chidren?

Please_Help_me_D

@JonB nice to hear that
As I understood I should go up from old/now until I meet ads::CDockWidget* dockWidget != nullptr condition, correct? Like:

{
ads::CDockWidget* dockWidget = qobject_cast<ads::CDockWidget*>(old->parent());
if (CDockWidget != nullptr){}
}

but in some while or for loop...

JonB

@Please_Help_me_D

ads::CDockWidget* dockWidget = nullptr;
while (old != nullptr && (dockWidget = qobject_cast<ads::CDockWidget*>(old)) == nullptr)
    old = old->parentWidget();
qDebug() << dockWidget;

Please_Help_me_D

@JonB thank you
But the loop ended and dockWidget is always nullptr. It takes about 7 cycles and there is no ads::CDockWidget*

JonB

@Please_Help_me_D
So in that case the old or now (you have written this loop on both, haven't you?!) in the focus change is not a descendent of your ads::CDockWidget* dockWidget. I never said it was, you did! Or you check children if whatever it is works that way.

Please_Help_me_D

@JonB yes I have written both old and now
Yes I'm trying to find this widget via old->children();. I need few minuts

Please_Help_me_D

@JonB this code can't find ads::CDockWidget* neither:

void MainWindow::onFocusChanged(QWidget* old, QWidget* now){
    if (old != nullptr){
        ads::CDockWidget* dockWidget = nullptr;
        QObjectList objList = old->children();
        int i = 0;
        while (i < objList.count() && dockWidget == nullptr){
            dockWidget = qobject_cast<ads::CDockWidget*>(objList.at(i));
            i++;
        }
    }

    if (now != nullptr){
        ads::CDockWidget* dockWidget = nullptr;
        QObjectList objList = now->children();
        int i = 0;
        while (i < objList.count() && dockWidget == nullptr){
            dockWidget = qobject_cast<ads::CDockWidget*>(objList.at(i));
            i++;
        }
    }
}

JonB

@Please_Help_me_D
So read up on what a ads::CDockWidget is/how it works. Your assumption in that QWidget::focusChanged(old, now) must lead to widgets either ancestors or descendants of this dock widget. I have no idea whether that is the case. Also your code may need to recurse down through children, no? At least start by finding out what old & now actually are in your focus change.

Please_Help_me_D

@JonB yes possibly I should have done the recursion down to the other children but it alredy becomes too complicated solution for such kind of a task.
Now I'm trying to set property not on CDockWidget but to some parent. I'm trying...

mrjj

Hi
It wont be the DockWidget that has the focus. it will be its widget/children.

I would call dumpObjectTree()
on old and now to see how they are made up.

Please_Help_me_D

@mrjj thank you for advice. Here is the output:

setFocus(Qt::OtherFocusReason);
setFocus(Qt::OtherFocusReason);
ads::CDockWidget::2D Window 
    QBoxLayout:: 
    QAction:: 
    QScrollArea::dockWidgetScrollArea 
        QWidget::qt_scrollarea_viewport 
            QVTKOpenGLStereoWidget:: 
                QVBoxLayout:: 
                QWindowContainer:: 
        QWidget::qt_scrollarea_hcontainer 
            QScrollBar:: 
            QBoxLayout:: 
        QWidget::qt_scrollarea_vcontainer 
            QScrollBar:: 
            QBoxLayout:: 
setFocus(Qt::OtherFocusReason);
setFocus(Qt::OtherFocusReason);
setFocus(Qt::OtherFocusReason);

So the focus should be on one of those?
By the way this tree is from ads::CDockWidget
Just a moment and I find tree for old
/
and here is tree for now object:

ads::CDockWidgetTab:: 
    QBoxLayout:: 
    ads::CElidingLabel::dockWidgetTabLabel 
    QPushButton::tabCloseButton

mrjj

hi
yes it should but we don't have to guess.
you can do
QWidget * fw = qApp->focusWidget();
and check out in the debugger (or qDebug its object name) to see what it is.

It should be possible to get hold of the Dock again to get your data back.

Please_Help_me_D

@mrjj QWidget * fw and now widget is the same. See the picture please

Please_Help_me_D

@mrjj now I'm trying to set property to the tabWidgets to wich CDockWidget belongs to:

QVTKOpenGLStereoWidget* MainWindowObjectCreator::createVTK2DWindow(){
    QVTKOpenGLStereoWidget* qvtkOpenGLStereoWidget = new QVTKOpenGLStereoWidget;
    ads::CDockWidget* dockWidget = new ads::CDockWidget("2D Window");
    dockWidget->setWidget(qvtkOpenGLStereoWidget);
    dockManager->addDockWidget(ads::RightDockWidgetArea, dockWidget);
    dockWidget->tabWidget()->setProperty("IsVisualization", 4443);
    //dockWidget->dumpObjectTree();
    return qvtkOpenGLStereoWidget;
}

but each time I manually change the focus the MainWindow::onFocusChanged(QWidget* old, QWidget* now) works twice:
first time now is the old window
second time is the new window
and when the second time this method works then I get the correct value of property:

void MainWindow::onFocusChanged(QWidget* old, QWidget* now){
    QWidget * fw = qApp->focusWidget();
    fw->dumpObjectTree();
    if (now != nullptr){
        now->dumpObjectTree();
        QVariant varia = now->property("IsVisualization"); 
    }
}

By the way this works only if the focused window is tabbed. Otherwise the focused widget is not a tabWidget(). So idea to set property to the tabWidget() doesn't seem to work