Dockable widgets: drag by body, not by header

[BigSmartFastAndrey]

Hello all.

I have this problem today. I want to drag QDockWidget objects inside QMainWindow catching them by body, but no by header. There are no dock widgets headers in application I written.

I tried to solve this problem putting body widget in the header entirely. But docking behaviour was really bad in this case...

Does anyone know the solution?

[wysota]

It should be possible to do what you want by intercepting mouse events and translating them so that the widget thinks it is dragged by the header.

[BigSmartFastAndrey]

Thanks for the reply,
eventually, I found the solution: remove unnecessary conditions from QDockWidgetPrivate class (mousePressEvent) and rebuild QtGui.

bool QDockWidgetPrivate::mousePressEvent(QMouseEvent *event)
{
#if !defined(QT_NO_MAINWINDOW)
    Q_Q(QDockWidget);
 
    QDockWidgetLayout *dwLayout
        = qobject_cast<QDockWidgetLayout*>(layout);
 
    if (!dwLayout->nativeWindowDeco()) {
        QRect titleArea = dwLayout->titleArea();
 
        if (event->button() != Qt::LeftButton ||
            !titleArea.contains(event->pos()) ||
            // check if the tool window is movable... do nothing if it
            // is not (but allow moving if the window is floating)
            (!hasFeature(this, QDockWidget::DockWidgetMovable) && !q->isFloating()) ||
            qobject_cast<QMainWindow*>(parent) == 0 ||
            isAnimating() || state != 0) {
            return false;
        }
 
        initDrag(event->pos(), false);
 
        if (state)
            state->ctrlDrag = hasFeature(this, QDockWidget::DockWidgetFloatable) && event->modifiers() & Qt::ControlModifier;
 
        return true;
    }
 
#endif // !defined(QT_NO_MAINWINDOW)
    return false;
}

bool QDockWidgetPrivate::mousePressEvent(QMouseEvent *event)
{
#if !defined(QT_NO_MAINWINDOW)
    Q_Q(QDockWidget);

    QDockWidgetLayout *dwLayout
        = qobject_cast<QDockWidgetLayout*>(layout);

    if (!dwLayout->nativeWindowDeco()) {
        QRect titleArea = dwLayout->titleArea();

        if (event->button() != Qt::LeftButton ||
            !titleArea.contains(event->pos()) ||
            // check if the tool window is movable... do nothing if it
            // is not (but allow moving if the window is floating)
            (!hasFeature(this, QDockWidget::DockWidgetMovable) && !q->isFloating()) ||
            qobject_cast<QMainWindow*>(parent) == 0 ||
            isAnimating() || state != 0) {
            return false;
        }

        initDrag(event->pos(), false);

        if (state)
            state->ctrlDrag = hasFeature(this, QDockWidget::DockWidgetFloatable) && event->modifiers() & Qt::ControlModifier;

        return true;
    }

#endif // !defined(QT_NO_MAINWINDOW)
    return false;
}

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[wysota]

Thanks for the reply,
eventually, I found the solution: remove unnecessary conditions from QDockWidgetPrivate class (mousePressEvent) and rebuild QtGui.

That's not really a solution unless you intend to break all programs using Qt on your system and some programs of everyone's using your application.