QApplication: modify Windows systray using QWinTaskbarButton

[ddonate]

Hi,

I have a QT application (QT .9.1) and I need to modify the icon in the windows taskbar, when I have an error. I am trying with QWinTaskbarButton, it seems to be really simple but I failed.

My application is a QtQuickControlsApplication (a QApplication), where I have a manager QObject class.

In this class I create a QQmlApplicationEngine, which I use to load the main QML.

From the documentation (http://doc.qt.io/qt-5/qwintaskbarbutton.html#details):

QWinTaskbarButton *button = new QWinTaskbarButton(widget);
    button->setWindow(widget->windowHandle());
    button->setOverlayIcon(QIcon(":/loading.png"));

QWinTaskbarButton *button = new QWinTaskbarButton(widget);
    button->setWindow(widget->windowHandle());
    button->setOverlayIcon(QIcon(":/loading.png"));

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But i don't know what to set in 'widget' and 'widget->windowHandle()'

I have tried to get a widget from the qApp but failed:

qApp->activeWindow() is NULL
	qApp->topLevelWindows().at(0) is valid, but failed:
 
	 QWinTaskbarButton *button = new QWinTaskbarButton(qApp->topLevelWindows().at(0));
	 button->setWindow(qApp->allWidgets().at(0)->windowHandle());
	 button->setOverlayIcon(QIcon(":/images/icon.png"));

qApp->activeWindow() is NULL
	qApp->topLevelWindows().at(0) is valid, but failed:

	 QWinTaskbarButton *button = new QWinTaskbarButton(qApp->topLevelWindows().at(0));
	 button->setWindow(qApp->allWidgets().at(0)->windowHandle());
	 button->setOverlayIcon(QIcon(":/images/icon.png"));

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I would appreciate any help,

Thanks in advance,
Diego

[ddonate]

I get the icon using the corresponding QML type of WinTaskbarButton. But I need to show a number over the icon, is it possible? Thanks