Correct style aware custom widgets don´t get the style applied anyway

darkgaze

It always worked until now. I don´t know what's going on but i got this code of a QPushButton customized:

@
class SmartModeButton : public QPushButton
{

private:

public:

SmartModeButton( ... );

protected:

void paintEvent(QPaintEvent *);

};
@

And i have this method

@

SmartModeButton::SmartModeButton( ... ): QPushButton(parent_)
{
(...)

setWindowFlags( Qt::Window | Qt::FramelessWindowHint );
setAttribute(Qt::WA_QuitOnClose, true);
setAttribute( Qt::WA_TranslucentBackground );

}

(...)

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

Adding this makes it work:

setStyleSheed("background-color:green");

But using a stylesheet as follows does nothing. It doesn´t understand the name of the widget, but i don´t get any errors.

@
/* ------------------ MODE BUTTONS ------------------------------------------*/

QPushButton
{ background-color: white; }

SmartModeButton
{ background-color: green; }
@

It still shows a white background. So it understand that it´s a button... but not a SmartModeButton.

Why?

The funny thing, it used to work. I don´t know what i changed, but it has no sense for me.

Thanks a lot.

Sam

For your SmartModeButton you can set an objectName

@SmartModeButton->setObjectName("SmartModeButton");@

and then in yout css file you can specify

@QPushButton#SmartModeButton
{
background-color: green;
}@

darkgaze

Yeah. That´s an idea.

BUT, and it´s a big BUT... if i do that, i cannot distinguish the different SmartModeButtons between them.

I mean:

I have 4 buttons from that class. Then i set the name for each of them so i can set :

SmartModeButton#name1
SmartModeButton#name2
SmartModeButton#name3
SmartModeButton#name4

Because i need different backgrounds for them, but the same behaviour. But by doing that, then all buttons are the same.

How would you do that?. And the big question: why did it stopped working??

If you have a custom class the stylesheet should work with it´s name just adding the paintEvent that way.

darkgaze

Any answers please?

Sam

For each instance of SmartModeButton you can set the objectName() and then accordingly you can change the background.

darkgaze

Sam, Thanks. but that´s the original question.

If you read the original post here, maybe you could see what´s going on. That is what is not working for me. It used to work but now it doesn´t. Doesn´t make sense, but it´s true.

andre

Does your class declaration contain the Q_OBJECT macro? The reason I ask is that you are not showing it, but it is vital for this use case. If there is no Q_OBJECT macro, things like getting the class name for an object don't work properly, and thus style sheets also can't use that.

darkgaze

OK. that´s the answer i was thinking about.

YEAH. definitely that´s what i did.... i removed the Q_Object because i had nothing like slots or signals for my class, so i removed it.

THANKS A LOT

andre

You're welcome.

Q_OBJECT does a lot more than just enable signals and slots. It is a core part of Qt's introspection mechanism. In general, I would advice to use the Q_OBJECT macro by default in every subclass you create of a QObject or class derived of QObject. That includes all widgets.

This way, you ensure that introspection features properly work. There are many scenarios where this is useful to have.