How can a custom QWidget be given a stylesheet pseudo-state?

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To give a custom QWidget a stylesheet pseudo-state, you can follow these steps:

1. Define a custom QWidget class that inherits from QWidget.

2. In the constructor of the custom class, set the object name to a unique identifier. For example:

class MyWidget(QWidget):
    def __init__(self, parent=None):
        super(MyWidget, self).__init__(parent)
        self.setObjectName("my-widget")

1. Define the pseudo-state in a stylesheet using the object name with the desired state. For example:

my-widget:pressed {
    background-color: red;
}

1. Apply the stylesheet to the custom widget using the setStyleSheet() method. For example:

my_widget = MyWidget()
my_widget.setStyleSheet("MyWidget:pressed { background-color: red; }")

1. Use the setProperty() method to set the widget's state to the desired pseudo-state. For example:

my_widget.setProperty("pressed", True)
my_widget.setStyleSheet("MyWidget:pressed { background-color: red; }")
my_widget.style().unpolish(my_widget)
my_widget.style().polish(my_widget)

Note that after setting the widget's property to the desired pseudo-state, you need to force the widget to reapply the stylesheet by calling unpolish() and polish().