Signal and Slot

by Martin Fitzpatrick Last updated FAQ
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Scoodood | 2020-08-06 18:18:52 UTC | #1

Dear Martin,

I am just done watching the Signal, Slots & Events video and done reading the Signals and Slots chapter on your PySide2 ebook. The sample code below is from your video

python 
self.windowTitleChanged.connect(self.onWindowTitleChange)

def onWindowTitleChange(self, s):   # <--- "s" ??
   print(s)

How do you know that the signal is also passing along a string variable s in this case? There are so many type of signals in Qt (pressed, released, drag, move....etc), how do we know each signal is passing along what-else when it is triggered? How do we find out?

Thanks

Impiastro_1 | 2020-08-07 15:59:20 UTC | #2

[quote="Scoodood, post:1, topic:394"] How do you know that the signal is also passing along a string variable s in this case? There are so many type of signals in Qt (pressed, released, drag, move…etc), how do we know each signal is passing along what-else when it is triggered? How do we find out? [/quote]

Create GUI Applications with Python & Qt5 by Martin Fitzpatrick — (PyQt5 Edition) The hands-on guide to making apps with Python — Over 10,000 copies sold!

More info Get the book

You can find your answers here: https://doc.qt.io/qtforpython/PySide2/QtGui/QWindow.html?highlight=windowtitlechanged#PySide2.QtGui.PySide2.QtGui.QWindow.windowTitleChanged

I think that in this case the signal emits only one unicode parameter.

ROb

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Signal and Slot was written by Martin Fitzpatrick .

Martin Fitzpatrick has been developing Python/Qt apps for 8 years. Building desktop applications to make data-analysis tools more user-friendly, Python was the obvious choice. Starting with Tk, later moving to wxWidgets and finally adopting PyQt.

Signal and Slot was published in faq on (updated ) . Feedback & Corrections welcome in our public issue tracker.

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