Thanks for the pull request! This looks good.

It would be nice if this did not require a dependency over qtquickcontrols2.
For example, this could be done with std::env::set_var("QT_QUICK_CONTROLS_STYLE", style)
another alternative would be to add and api in QmlEngine to be able to pass arguments to the QApplication (constructed by QmlEngineHolder)

Since all the api of QQuickStyle are static anyway, a struct does not really make sense in the rust API, it could just be functions in a module.

Okay, will do, thanks for the feedback!

Which one would you prefer? Using the envvar or adding it to QmlEngine? I personally would prefer the QQuickStyle version as it mirrors the Qt api => therefore less surprising.

You are right, mimicking the QQuickStyle API is probably the best

Done. I'm using QString because it matches the Qt API most closely. Is this okay or should I use &str? In this case it involves unnecessary overhead. EDIT: Or should it be &QString?

Unrelated: I think it might also make sense to use a binding generator to offer a more complete binding set on top of qmetaobject-rs, perhaps as a different crate. What do you think?

yes, &str is maybe best.

I think it might also make sense to use a binding generator to offer a more complete binding set

The problem with binding generator is that it is hard to automatically derive a proper safe rust API out of a C++ API automatically.