Have a QWidget expand inside and resize with QScrollArea

[qwasder85]

How can I get a QWidget to expand within the visible area of a QScrollArea and also resize with said ScrollArea? Setting the QSizePolicy to Expanding results in an empty ScrollArea.
Is there a proper way without catching resize signals from the ScrollArea and relaying them to the QWidget?

My goal is to have a QWidget resize down to its minimum size and then display scrollbars if the parent gets even smaller.

    // This results in an empty QScrollArea
    QStackedWidget* p_stacked_widget = new QStackedWidget;
    p_stacked_widget->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding );
    p_stacked_widget->setContentsMargins( 0, 0, 0, 0 );
    p_stacked_widget->setMinimumSize( 500, 400 );

    // This QScrollArea is set to "Expanding" in a parent widget
    QScrollArea* p_scroll_area = new QScrollArea;
    p_scroll_area->setContentsMargins( 0, 0, 0, 0 );
    p_scroll_area->setWidget( m_p_stacked_widget );

Maybe I'm going about this all wrong?

[raven-worx]

@qwasder85
for this case you need to subclass QScrollArea and in it's resizeEvent you need to resize the content widget:

MyScrollArea::resizeEvent( QResizeEvent* event )
{
    QScrollArea::resizeEvent( event );

    if( QWidget* w = this->widget() )
    {
          QSize viewportSize = this->viewport()->size();
          w->resize( viewportSize.boundedTo( w->minimumSize() );
    }
}

Something like this.
But i leave it to you, to calculate the size correctly beforehand depending if a scrollbar is needed or not.