Adding constraint to css file for a QWidget - c++

Question

I use a css file in my Qt Projets, with Visual Studio 2010.
main.cpp :
QApplication app(argc, argv);
// Mise en place du style CSS
QFile File("Resources/style.css");
File.open(QFile::ReadOnly);
QString styleSheet = File.readAll();
File.close();
app.setStyleSheet(styleSheet);
A part of my css file :
QWidget#contenuDescription {
background-color: rgb(0, 150, 255);
border: 2px solid rgb(0, 0, 255);
border-top-left-radius: 10px;
border-top-right-radius: 10px;
border-bottom-right-radius: 10px;
border-bottom-left-radius: 10px;
}
QLabel#nom1 {
background-color: rgb(0, 150, 255);
font-size: 36px;
}
QLabel#nom2 {
background-color: rgb(0, 150, 255);
font-size: 24px;
}
QLabel#nom3 {
background-color: rgb(0, 150, 255);
font-size: 20px;
}
I want to change the color to my QLabels : nom1, nom2 and nom3 when bool m_changeColor == true.
I know we can use ::hover if we want to change the style sheet when the mouse is on the QLabel. Something like this does it exist for my problem ?
Thank you in advance for your answer.

Answer 1

You need to use properties:
Q_PROPERTY(bool changeColor ...)
Os set a property dynamically:
nom1Label->setProperty("changeColor", true);
Then in CSS:
QLabel#nom1[changeColor="true"] {
...
}
Also note:
Warning: If the value of the Qt property changes after the style sheet
has been set, it might be necessary to force a style sheet
recomputation. One way to achieve this is to unset the style sheet and
set it again.