[QGIS-Developer] Using QML widget as editing widget

[Matthias Kuhn]

Hi Bo,

With the qml widget, you can mostly do shiny data representation, it's not
optimized for editing.
Have a look at this blog post from my colleague Dave
https://www.opengis.ch/2018/11/06/qml-widgets-qgis/

It's also possible to create custom widgets with python, but it requires a
few classes to be implemented.
The main entry point is registering a custom QgsEditorWidgetFactory with
https://qgis.org/pyqgis/3.40/gui/QgsEditorWidgetRegistry.html#qgis.gui.QgsEditorWidgetRegistry.registerWidget
and from the factory create new QgsEditorWidgetWrappers. This will create
new widgets which can (if you want) also be based on
https://doc.qt.io/qt-6/qquickwidget.html and render QML this way.
There is an example on
https://github.com/opengisch/stdm/blob/master/stdm/ui/forms/spatial_unit_form.py
(without QML).

Best wishes
Matthias

On Sat, Jun 7, 2025 at 4:09 PM Bo Victor Thomsen via QGIS-Developer <
qgis-developer at lists.osgeo.org> wrote:

> Hi list -
>
> I've been doodling a while using the QML widget i QGIS (version 3.42,
> Windows) : and I have a question: Is it possible to design a editing widget
> using the QML widget as a base?
>
> And the why ? :
>
> I have a postgres table, where one of the fields is a "jsonb" object. I
> can *show* the json values using the "Json view" widget or even make the
> elements of the json object editable using the "key/value" widget (my json
> object are "flat": only a series of key/value pairs).
>
> However, I would like to add a drop-down value list to some of the
> elements in the jsonb field, so the user can choose a value from a list
> instead of writing the value using a keyboard.
>
> As far as i can see, i have couple of potential choices: Try to subclass
> the "key/value" widget if that's possible from python and extend the
> functionality.
>
> Or design a QML document which shows the json element in a number of
> combo-boxes.
>
> And hence the question: Can i replace the field value with the changed
> version from a QML widget. And how ??
>
>
>
>
> --
> Med venlig hilsen / Best regards
>
> Bo Victor Thomsen
>
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