> 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
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