No, there is no such widget, but there is another very simple way to do this. You can play gif animation to do this. For example:
QLabel *lbl = new QLabel;
QMovie *movie = new QMovie("G:/loader.gif");
lbl->setMovie(movie);
lbl->show();
movie->start();
You can get gif-animation from here or use another gif.
I think that it is the easiest way because you can create this animation in app with timer, color changing and so on, but it requires a lot of work and time. But QMovie is powerful and easy to use class.
