Custom checkable / toggleble QFrame widget

Question

How can I make a custom widget (derived from "QFrame") contain a support to be checkable/toggleble? How to make Qt's stylesheet (CSS) to be aware that my widget was checked/toggled by user?

Is there some kind of signal or property that I need to use in my custom widget?

I don't want to use (i.e.) QPushButton because I need my button widget to use Qt's .ui file.

I.e. when using QPushButton - things are simple:

QPushButton#btnName:focus:pressed { border-image: url(ThemesPathKey/menu-top-h.png);    }
QPushButton#btnName:checked {   border-image: url(ThemesPathKey/menu-top-h.png);    }
QPushButton#btnName:hover { border-image: url(ThemesPathKey/menu-top-h.png);    }

I need something similar for my custom button widget.

Thanks.

Answer 1

You can use hover and focus for a custom widget, but checked is supported for buttons and check boxes only.

To replace checked you can use a custom property:

QPushButton#btnName[checked="true"] {   border-image: url(ThemesPathKey/menu-top-h.png);    }

when your widget is clicked toggle checked property like this:

void mousePressEvent(QMouseEvent*) override
{
    bool checked = property("checked").toBool();
    setProperty("checked", !checked);
    style()->polish(this);
}

Answer 2

For hovering, you could use the same approach with any derived widget:

class MyClass : public QFrame
{
<...>
}

MyClass a;
a.setStyleSheet("MyClassa:hover{<...>}"); //this will work
a.setStyleSheet("MyClass#a:hover{<...>}"); //and this will work
a.setStyleSheet("QFrame:hover{<...>}"); //Even this will work, too

Checking/unchecking is more complex. Frames do not have check states, so you'll have to implement it yourself.

class MyClass : public QFrame
{
public:
    <...>
protected:
    void mousePressEvent(QMouseEvent * e) override
    {
        checked_ = !checked_;        
        if(checked)
            setStyleSheet("border:1px solid black;");
        else
            setStyleSheet("border:0px;"); 
    }
bool checked_;
}

or something like this

class MyClass : public QFrame
{
public:
    <...>
protected:
    void paintEvent(QPaintEvent * e) override
    {
        if(checked)
        {
        //draw something
        }
        else
        {
        //draw something else
        }
    }
    bool checked_;
}