PySide Signal with Argument

Question

QGroupBox has the signal clicked which has an optional checked parameter. Suppose I'm trying to connect a slot to it inside of some class like so: box.clicked.connect(self.func) , so the declaration of the slot must be def func(self, checked) , but func is being called with only one argument. How do I get the desired behaviour of func being called with both self and the optional checked arguments?

Answer 1

The behaviour of signals with optional default parameters differs between PyQt and PySide. In PyQt, the default parameter is always sent, but in PySide you have to explicitly request it:

    box.clicked[bool].connect(self.func)

This is a much better design choice, I would say, as the PyQt behaviour can often lead to bugs if you forget that a default value will be sent even though you didn't ask for it. A case of explicit being better than implicit...