问题:

I'm using the Qt library to show a slideshow on the second monitor when the user isn't using the second monitor. An example is the user playing a game in the first monitor and showing the slideshow in the second monitor.

The problem is that when I open a new window in Qt, it automatically steals the focus from the previous application. Is there any way to prevent this from happening?

回答1:

It took me a while to find it but I found it: setAttribute(Qt::WA_ShowWithoutActivating);

This forces the window not to activate. Even with the Qt::WindowStaysOnTopHint flag

回答2:

Widgets don't accept focus by default but presumably you haven't created a plain widget? Which subclass was it? QMainWindow or something else?

It's possible the window subclasses default to accepting focus so try explicitly calling QWidget::setFocusPolicy with Qt::NoFocus before calling QWidget::show().

Also, make sure you're not calling QWidget::activateWindow() on the window or any of its widgets at any point.

回答3:

If you want to make floating preview box/ any other widget just use below

thumbnail = new QLabel;
thumbnail->setAttribute(Qt::WA_ShowWithoutActivating);
thumbnail->setParent(0);
thumbnail->setWindowFlags(Qt::Tool | Qt::FramelessWindowHint|Qt::WindowStaysOnTopHint);

Qt::Tool is important flag to make it work. I mean not stealing focus.