Proper PyQt5 signal & slot syntax

[d_stranz]

#ChangeSignals.increase.connect(self.signal_handle r)

I am no PyQt expert, but in C++, you would need an instance of the ChangeSignals class as an argument of the connect() statement. Otherwise, how does connect() know which instance of the signalling class to connect to? Signals aren't broadcast, there must be explicit signal-slot or signal-signal connections between instances of the classes on each end. The only argument you supply is your signal_handler slot (and I assume that in PyQt connect() defaults the SignalWatchers instance on the receiving end (slot) to "self").

[illuzioner1]

Thank you for the response. I had also tried using an instantiated version of the class, but was still getting errors on connect.

It turns out that the line 110 above:
@pyqtSlot

was causing the issue. I don't know why, but when I commented out this line everything worked! It looks like that decorator is only for non-class functions.

Thanks!

[d_stranz]

Maybe it is my ignorance of PyQt and python in general, but where is the instance of ChangeSignals that forms the sending (signal) end of the increase() signal? I see you have defined a global variable named sig that is a ChangeSignals instance, but where is that used in the connect() statement?

The only thing I can imagine is that ChangeSignals.increase.connect() must create a temporary instance of ChangeSignals that provides the signalling end and once __init__ exits this goes out of scope, gets destroyed, and the connection broken. Shouldn't this be "sig.increase.connect()" instead?

[illuzioner1]

No, you didn't miss anything. I went back to the version where I instantiated the class and used that signal, but I didn't update the code in my question. THEN I removed the pyqtSignal decorator.

Sorry to throw you off!