Blacking out the screen

My client wants something artsy. The application has a screen full of widgets. If the user clicks the "X" go-away button they want the main screen to be over laid with a 85% semi-transparent black, and have an "Are You Sure?" dialog appear.

I have the dialog working just fine, but my black overlay is not working. Probably due to a trivial newbie mistake.

The situation is that the main window contains a single QStacked widget, each page of which contains a complicated QWidget composed of numerous controls. In the main window I have sub-classed closeEvent(). This is the code I'm using to vainly to apply an 85% black:

Code:

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int theIndex = m_stackedWidget->currentIndex();
QWidget *currentWidget = m_stackedWidget->widget(theIndex);
QWidget	*crepuscularWidget = new QWidget(currentWidget);
crepuscularWidget->resize(currentWidget->size());
QPainter painter(crepuscularWidget);
painter.setOpacity(0.85);
painter.fillRect(crepuscularWidget->rect(), QBrush(Qt::black));
crepuscularWidget->repaint();
// then follows the code to put up the "Are You Sure?" modal dialog

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Originally this was more compact, I've expanded it to aid debugging (e.g., the first line used to end in = m_stackedWidget->widget(m_stackedWidget->currentIndex()))

It doesn't work.

I've tried initializing crepuscularWidget with the main window, stackedWidget, as well as m_stackedWidget->widget(n). I've tried not using crepuscularWidget at all, instead initializing painter with the main window, stackedWidget, and m_stackedWidget->widget(n). I've used crepuscularWidget->repaint() and crepuscularWidget->update(). Nothing seems to work.

Can anybody see what I am doing wrong?

You have to call show() on the new widget :).

Alas, I put in a crepuscularWidget->show() right before the crepuscularWidget->repaint(), but it had no effect. It still is not drawing. Thanks for the suggestion anyway, it was stupid of me to forget the show().

Oh... What was I thinking...
You can't paint a widget outside its paintEvent...

So, there's your reason.

Ah, that would certainly do it. Thank you very much!

Yes, I moved the drawing code into the CrepuscularWidget's paintEvent, and it is working perfectly. Thank you very much!