Changing QPalette of widget inside QGraphicsScene not working

vinci

Hello

I'm trying to change the color of a widget which inherits from QFrame using QPalette. This widget is then used in a QGraphicsScene.

class State : public QFrame {
public:
  State(QString name, QWidget* parent = nullptr) : QFrame{parent} {
    QVBoxLayout* layout{new QVBoxLayout};
    label_->setText(name);
    layout->addWidget(label_);
    setLayout(layout);
    setFrameStyle(QFrame::Box);

    // Not working at all
    QPalette palette{QFrame::palette()};
    palette.setColor(QPalette::Base, Qt::red);
    setPalette(palette);
  }

private:
  QLabel* label_{new QLabel};
};

Sadly this doesn't seem to do anything? I've tried changing various ColorRoles (e.g. Window) but the widget still looks the same. I'm currently using Qt 6.3.0.

vinci

I just realized that it actually does work, but only if I disable my stylesheet.
Is this behavior wanted? Does a stylesheet take precedence over locally set palettes?

JonB

@vinci said in Changing QPalette of widget inside QGraphicsScene not working:

Does a stylesheet take precedence over locally set palettes?

Yep.

vinci

Oh I see thank you.

What's the recommended best practice to "slightly" change a widgets style (e.g. border color) then in case I can't change the applied stylesheet? I really only need some kind of visual cue for two different kind of states.

SimonSchroeder

@vinci QPalette is really unreliable. Some colors cannot be changed by the QPalette and it depends on the style which palette colors influence which part of the widgets. So, I advocate to try to not use QPalette at all.

The best way is actually using stylesheets. You can just set a stylesheet on just this one QFrame object. It can be a small stylesheet changing only this one little thing. Everything else will be inherited from your current global stylesheet.

vinci

Alright, I'll look into that.
Thanks for the fast answers!

SGaist

Hi,

I would recommend a look at this excellent article from KDAB about using custom QStyle.