> On 28 Nov 2024, at 16:02, Fabian Kosmale via Development
> <development@qt-project.org> wrote:
>
> Note however that using QMetaType has the limitation that it will only allow
> calling the default constructor. While all widgets should be default
> constructible, you might want to construct e.g.
> `QDialogButtonBox::QDialogButtonBox` with some specific button). Could be
> worked around in the bindings, though.
>
> Fabian
Yup; although all parameters that can be set through the constructor should
also be settable via properties on a default-constructed widget, without any
significant negative impact. E.g. in QDialogButtonBox, both orientation and
standardButtons are properties.
If there’s anything missing then that should be easy to fix.
Volker
> On 28.11.24 15:45, Volker Hilsheimer via Development wrote:
>>> On 28 Nov 2024, at 15:01, André Somers via Development
>>> <development@qt-project.org> wrote:
>>>
>>> Hi Marcus,
>>>
>>> On 28-11-2024 14:29, Marcus Tillmanns via Development wrote:
>>>> Hi Shawn,
>>>>
>>>>> On 28. Nov 2024, at 13:15, Shawn Rutledge via Development
>>>>> <development@qt-project.org> wrote:
>>>>>
>>>>>
>>>>>> On Nov 28, 2024, at 09:08, Fabian Kosmale via Development
>>>>>> <development@qt-project.org> wrote:
>>>>>> - Some are already (indirectly) exposed via Q_PROPERTY; should anyone
>>>>>> decide to expose those Widgets to QML (or some other language binding
>>>>>> working on the meta-object system), this would cause some friction
>>>>>> because there will be name clashes (QWidget::geometry() vs the geometry
>>>>>> property).
>>>>> Indeed; given that the UI designer application, and QUiLoader, are able
>>>>> to dynamically instantiate every kind of widget, and all the interesting
>>>>> properties are, well, properties, it seems doubtful that there are many
>>>>> things that you couldn’t already do in a scripting language either. And
>>>>> some property setters are already slots, which already makes them
>>>>> invokable, and is also a bit redundant already (if QProperty can set the
>>>>> property, the main reason for making the setter into a slot besides is to
>>>>> be able to connect a signal to it, right?)
>>>> QUiLoader seems to have a fixed list of Widgets it can instantiate?
>>>> (“widgets.table”) And for custom widgets it expects you to implement
>>>> QDesignerCustomWidgetInterface.
>>>>
>>>> And then for the properties, most is there you are right and I was
>>>> starting to think it should all be easy, but pretty important stuff like
>>>> “QWidget::show()” is not covered by a property sadly. I will investigate
>>>> how much of the important stuff is missing first, maybe just setting up a
>>>> list of classes and their Constructors, plus the important QWidget
>>>> functions is small enough that I no longer wish for Q_INVOKABLE all the
>>>> things :)
>>>
>>> You may want to look into leveraging Declarative Widgets. This is an
>>> experimental/PoC implementation of using widgets from QML. Rather than
>>> extending the widgets classes themselves, it uses the extension mechanism
>>> to provide the missing features from the QML (scriptable) perspective.
>>>
>>> Cheers,
>>>
>>> André
>> With the meta type system, you can construct any Q_OBJECT-type by name, as
>> long as it’s registered:
>> #include <QtWidgets>
>> int main(int argc, char *argv[])
>> {
>> QApplication app(argc, argv);
>> qRegisterMetaType<QPushButton>("QPushButton");
>> const QMetaType pbType = QMetaType::fromName("QPushButton");
>> QObject *pb = static_cast<QObject *>(pbType.create());
>> Q_ASSERT(pb);
>> pb->setProperty("text", "Ok");
>> pb->setProperty("visible", true);
>> return app.exec();
>> }
>> The call to qRegisterMetaType could be done in the code that implements the
>> binding.
>> Volker
>
> --
> Fabian Kosmale
> Manager R&D
>
> The Qt Company GmbH
> Erich-Thilo-Str. 10
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> fabian.kosm...@qt.io
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