fix a bug of load_ui function for pyside

[sol87]

If there are custom widgets in ui files, we must register them before loader.load() in pyside. So I make a new function for that.

[mottosso]

Thanks @sol87! Could you make an example or test for this functionality as well? Have a look in the tests.py file for how you could write one.

[mottosso]

And also take a gander at the error message, looks like something went out the window with PySide2 for both Python 2 and 3.

See the developer guide for how you could run tests locally, of keep committing to your repository to test here.

[fredrikaverpil]

Hi @sol87 and thanks for this!

Regarding adding custom widgets support, I did implement that into load_ui back in an old PR which we collectively decided to close.

You can view the full load_ui implementation I was proposing here: https://github.com/fredrikaverpil/Qt.py/blob/3daabe95bff0e09454595899543a3ab1d75c4e70/Qt.py

However, this was not merged. We came to the conclusion that this would add functionality to Qt.py which wasn't maintained by PySide/PyQt/Qt but instead had to be maintained by us. For end-users this would mean relying on features which were actually not developed in co-operation with neither the PySide development team or the PyQt development team. And the same goes for adding the "base_instance" argument, which I personally needed at the time.

We actually defined some of our guidelines based on that discussion:

Henceforth, Qt.py is about linking together commonalities between PySide2 and other bindings, and documenting differences, so as to foster a mindful developer of cross-compatible software.

This is in contrast to wrapping all functionality that differs PySide2 with our own ad-hoc implementations, which we believe will cause more problems than it solves long-term.

This should've been added to the development guidelines, which @mottosso already mentioned, but now when I glance through it, I can't see it being mentioned so we should probably fix that.
– @mottosso I can see "No implementations = No bugs." but that's a little vague?

Okay... back to my story. Since I personally set out to add a base instance argument to load_ui, I decided it would be useful to at least add examples of how load_ui could be extended to support this (although not making load_ui) support it out of the box, and therefore steering users in a more compatible direction in terms of development. These examples are part of Qt.py testing and reside here: https://github.com/mottosso/Qt.py/tree/master/examples/load_ui

I propose that instead of adding custom widgets support to Qt.py directly we add one another example, where it is shown how such functionality can be added to load_ui. In the end, this would just mean that for the majority of users, load_ui is a simple function doing simple remapping - and for those who need more complex functionality, examples are provided on how to extend load_ui.

Please let me know what you think.

[sol87]

Sure. I will make a example file soon.

[sol87]

Hi @fredrikaverpil . I have checked your hack. It seems cool. I believe you make this decision based on good reasons :)

[mottosso]

Well put, @fredrikaverpil, and thanks for understanding @sol87!