PySide2与PyQt5的QtQuick2控件槽函数疑问：QML为何可直接调用？

Great question—this is one of those small syntax differences that trips up folks switching between PyQt5 and PySide2, but the core reason boils down to how each binding implements Qt's underlying mechanics. Let’s break it down:

• Different names, same core purpose
  Both @pyqtSlot() (PyQt5) and @Slot() (PySide2) are decorators that register your Python method with the Qt Meta-Object System (MOC). This system is what lets Qt (and QML) recognize and call your Python functions as slots—without this registration, QML wouldn’t be able to find or invoke the method at all.

• Naming comes from each project's philosophy
  PyQt5 is developed by Riverbank Computing, which tends to add a pyqt prefix to its Qt-specific decorators and classes to distinguish them from the raw C++ Qt API. PySide2, on the other hand, is Qt’s official Python binding, so it uses names that mirror the C++ Qt API directly (in C++ you’d declare slots with the slots keyword, hence @Slot()).

• QML doesn’t care about the decorator name—only the registration
  When you use either decorator, it adds the necessary metadata to your class so the Qt MOC can pick it up. QML interacts with your Python code through this metadata, not the decorator’s name. As long as the method is properly registered as a slot, QML can locate and call it regardless of which decorator you used.

Even though PySide2’s docs are often outdated or incomplete, these small syntax gaps are usually just cosmetic—both bindings are implementing the same Qt under the hood. Keep experimenting, and you’ll get the hang of these quirks in no time!

内容的提问来源于stack exchange，提问作者ImRaphael