Qt setStyleSheet it not working

yugosonegi

I have a class called MyWidget and I'm trying to load a global style using this code on my main.cpp:

QFile file(":/style.qss");
file.open(QFile::ReadOnly);
QString stylesheet = file.readAll();
application.setStyleSheet(stylesheet);

And it's working, the problem now is that I want to change in that file the background color of my MyWidget. I tried to use the setObjectName('MyWidget') and do something like:

QWidget#MyWidget {
    background-color: yellow;
}

But it doesn't work. What to do?

kenchan

@yugosonegi
If MyWidget is a subclass of QWidget did you see the docs related to this...

"QWidget
Supports only the background, background-clip and background-origin properties.
If you subclass from QWidget, you need to provide a paintEvent for your custom QWidget as below:

void CustomWidget::paintEvent(QPaintEvent *)
{
QStyleOption opt;
opt.init(this);
QPainter p(this);
style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);
}

The above code is a no-operation if there is no stylesheet set.
Warning: Make sure you define the Q_OBJECT macro for your custom widget."

Other than that it should work.

yugosonegi

With your answer it means that I can't chance the background the way I'm doing? I can't understand your answer right.

mrjj

@yugosonegi

Hi
mr @kenchan says

If you MyWidget is a class you made yourself. ( versus one of Qts just named MyClass)
you need to do as he shows in your class
paintEvent for a stylesheet to have any effect.

So is MyWidget your own class ?
as in
class MyWidget : QWidget {}

yugosonegi

Yes, it's a subclass of QWidget.

mrjj

@yugosonegi
Ok, for such a custom widget , you must use the code shown in paintEvent for it to use
stylesheet at all. ( you can have extra code for own drawing but QStyleOption and drawPrimitive
should be used also/first)