Change property of a class during runtime

[CJha]

Hi, I would like to change the QAbstractSpinBox::ButtonSymbols during runtime. I tried changing it in my own subclass of QProxyStyle:

void GuiStyle::drawComplexControl(QStyle::ComplexControl control, const QStyleOptionComplex* option, QPainter* painter, const QWidget* widget) const
{
	if((control == QStyle::CC_SpinBox) && (spinBoxBtns == false)) {
		const QStyleOptionSpinBox* buttonOption = qstyleoption_cast<const QStyleOptionSpinBox*>(option);
		QStyleOptionSpinBox newBtnOption = *buttonOption;
                if(spinBoxBtns)
		    newBtnOption.buttonSymbols = QAbstractSpinBox::UpDownArrows;
                else
                    newBtnOption.buttonSymbols = QAbstractSpinBox::NoButtons;
		QProxyStyle::drawComplexControl(control, &newBtnOption, painter, widget);
		
	}
	else {
		QProxyStyle::drawComplexControl(control, option, painter, widget);
	}
}

but it ends up not readjusting the alignment of the text and so if I remove the up-down button then the text ends up being not in the centre anymore. Then I tried doing it on a per-object basis:

void applySpinBoxButtons(bool val)
{
	QWidgetList allWidgets = qApp->allWidgets();
	for(QWidget* wid : allWidgets) {
		QString str = wid->metaObject()->className();
		if(str == "QSpinBox") {
			QSpinBox* spin = static_cast<QSpinBox*>(wid);
                        if(val)
			    spin->setButtonSymbols(QAbstractSpinBox::UpDownArrows);
                        else
                            spin->setButtonSymbols(QAbstractSpinBox::NoButtons);
		}
	}
}

It works, but this does not affect any new QSpinBox that is created (e.g. in QColorDialog). Is there any way I can do this on a class basis like QApplication allows fonts and palettes to be set on a class basis using void QApplication::setPalette(const QPalette &palette, const char *className = nullptr)?