Qwidgets in QML

Jupiter

Hi,

is it somehow possible to use Native QtWidgets (like a QCombobox) in a QDeclarativeItem? I know about the labs projects and things about QML controls. but I need a stable solution.

thanks

frankcyblogic.de

I think mixing QML and QWidget is not easy, nor future prove. But using it side by side is easy. You can easily control your QWidget based application from QML by declaring your own items which emit/receive signals.

thisisbhaskar

There are couple of things..

Do you want to create instances of native qt widgets inside qml or
You want to make a concrete native qt widget create in C++ class and make it available inside qml??

The second one is easy and make sense to do it. But first method is bit hard as mostly not all useful properties/methods are exposed to meta system via Q_PROPERTY/Q_INVOKABLE, so are not available inside qml.

Jupiter

i want do use a ComboBox inside QML, but it seems too complicated for me to make a qml combobox.

dialingo

Qt comes with an example that shows how to embedded widgets in qml:
examples/declarative/cppextensions/qwidgets

There are a couple of problems though:
You can not nest widgets with QML easily.
There is a clash of philosophies. In C++ you keep pointers to widgets to manipulate them. In QML visual items adapt to property changes. Having pointers to widgets breaks the separation between C++ (back end) and qml (front end).

Jupiter

i dont have the folder you mentioned in my qtsdk folder ? arent there all examples in the sdk?

thisisbhaskar

you can refer to http://doc.qt.nokia.com/4.7/qdeclarativeexamples.html#c-extensions

Jupiter

thanks that helps

njeisecke

I've had all kind of troubles (painting artefacts, bad performance, ...) with embedding QWidgets in QML scenes. It just does not work very well.

I guess the Qml Desktop Components won't become official/stable before Qt 5 so for desktop applications that must have a native look and feel I would recommend using the classic QWidget approach.

dialingo

Another warning: Font hinting is also a problem with embedded widgets. Do not expect fonts to appear as clean as they do on QML Text elements or on non-embedded widgets.

Dmitriy V. Shmykov

That's it http://developer.blackberry.com/native/documentation/cascades/dev/integrating_cpp_qml/