Why is PyQt connect() syntax so verbose?

问题

I'm just learning PyQt and looking at the Signals and Slots mechanism. I'm a bit baffled by the verbose syntax. Why do we have:

self.connect(dial, SIGNAL("valueChanged(int)"), spinbox.setValue)

I would much prefer to write the following:

self.connect(dial.valueChanged, spinbox.setValue)

Can anyone tell me why the connect() syntax needs to be so explicit/verbose?

回答1:

You can use PyQt's new style signals which are less verbose:

self.connect(dial, SIGNAL("valueChanged(int)"), spinbox.setValue)

Becomes:

dial.valueChanged.connect(spinbox.setValue)

回答2:

Luper's answer is much better than this one, but for the sake of completeness...

The ugly "old style" syntax is an anachronism from the C++ world - just look at the syntax those guys have to work with! Yucky...

回答3:

An even shorter way is to assign the signal name to the function in the keyword arguments of the constructor e.g. QDial(valueChanged=spinbox.setValue). PyQt will automatically connect the valueChanged() signal to spinbox.setValue().

来源：https://stackoverflow.com/questions/50184839/typeerror-native-qt-signal-is-not-callable-when-i-try-to-convert-pyqt4-to-pyqt5