[PyQt] Fwd: QObject::connect: Parentheses expected, signal Actor::

Phil Thompson phil at riverbankcomputing.com
Thu Feb 28 22:00:57 GMT 2019


On 28 Feb 2019, at 9:10 pm, Maxime Lemonnier <maxime.lemonnier at gmail.com> wrote:
> 
> When I derive a class from QObject and use it from qml, I get annoying warnings if I declare a property in the qml declaration, and bind that property anywhere.
> 
> I get one 
> 
> 'QObject::connect: Parentheses expected, signal MyClass::'
> 
> per binding, which can amount to a lot. so many in fact that it slows down startup time of my app significantly (.5s on Linux, 15-20s on Windoze).
> 
> I can fix it by deriving from QQuickItem instead, but then I hit a mysterious:
> 
> 'TypeError: a maximum of 30 QQuickItem types may be registered with QML'
> 
> Where does this limitation comes from?, I get no hit from google on it. 

It's an arbitrary PyQt limit. It can be increased but I wouldn't want to (for example) increase it by 10x.

If you have a short script that demonstrates the original problem I can look at it.

Phil


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