Style Sheet Syntax background

I want to have the background only from a QWidget black. The background from the QPushbuttons, QSliders etc. shoud be normal.
I use the Style-Syntax:

QWidget {
background-color:rgb(20, 20, 20);
}

I read in the Qt Assistant (Stylesheet-Syntax) that i must make bevore the QWidget a point:

.QWidget {
background-color:rgb(20, 20, 20);
}

I have now the problam that this didn't work.

Thanks for help.

well it works, but only for QWidgets! No subclass, even not your own if they only inherit QWidget.

maybe you provide a small executable example showing your problem.

I had this code and it didn't work, the background from the QWidget wouldn't be darker:

Code:

---

QColor bgColor = palette().color(QPalette::Window).darker(110);
	QString styleSheet = ".QWidget {  background-color:rgb(%1, %2 ,%3);}";
	styleSheet = styleSheet.arg(bgColor.red()).arg(bgColor.green()).arg(bgColor.blue());
	setStyleSheet(styleSheet);

---

Well your are setting the style sheet on what kind of object? I seems that is is a subclass, which, as told, wont work. But you can use ".NAMEOFYOURCLASS" and then it should work.

Yes, it's a own subclass from QWidget. I use:

Code:

---

QString styleSheet = ".myOwnClass {background-color:rgb(%1, %2, %3)}";

---

but it didnt' work. I think it's a problem of the syntax, because

Code:

---

QString styleSheet = "QWidget {background-color:rgb(%1, %2, %3)}";

---

works and

Code:

---

QString styleSheet = ".QWidget {background-color:rgb(%1, %2, %3)}";

---

didn't work.

I solved the problem:

Code:

---

QString styleSheet = "QWidget#MyOwnClass {background-color:rgb(%1, %2, %3)}";

---

Now it works.
But I don't now why the other syntax don't work.

Thanks for your efforts