Error importing extended QML type

Tom asso

Trying to extend Surface3DSeries, adding a property “topoFile” which has value of type QString. But the QML editor seems unable to import the extended type. I define the C++ class which will extend Surface3DSeries, with a Q_PROPERTY “topoFile”:

class TopographicSeries : public QObject
{
 Q_OBJECT
 Q_PROPERTY(QString topoFile READ getTopoFile WRITE setTopoFile )

I register the extended type in main.cpp:

int main(int argc, char *argv[])
{
 QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

 QGuiApplication app(argc, argv);

 qmlRegisterExtendedType<QSurface3DSeries, TopographicSeries>("Test", 1, 0, "Surface3DSeries");

But the QML view displays "QML module not found" when I try to import the extended type in main.qml:

import QtQuick 2.12
import QtQuick.Window 2.12
import QtDataVisualization 1.0
import Test 1.0   * QML module not found (Test)

All of my project files are in the same directory, and my .pro file includes this:

# Additional import path used to resolve QML modules in Qt Creator's code model
QML_IMPORT_PATH = $$PWD

Does anyone know what I am doing wrong?

Thanks
Tom

Tom asso

Another mysterious problem. As a test I removed reference to the Surface3DSeries "topoFile" property from main.qml, and instead get topography from an ItemModelSurfaceDataProxy defined in the qml. However now when I run the app I get this error in the output:

QQmlApplicationEngine failed to load component
qrc:/main.qml:19 Invalid property assignment: "seriesList" is a read-only property

seriesList is a property of Surface3D. Why in the world would something be trying to write that property if the qml makes no reference to the extended QSurface3DSeries "topoFile" property? If I remove the call to qmlRegisterExtendedType() in main.cpp, the app executes without error.

Here is the qml file:

import QtQuick 2.0
import QtQuick.Window 2.12
import QtDataVisualization 1.2

Window {
    visible: true
    id: mainWindow
    width: 640
    height: 480
    title: qsTr("TopoSeries test")

    Item {
        width: 640
        height: 480

        Surface3D {
            width: parent.width
            height: parent.height
            Surface3DSeries {
                ItemModelSurfaceDataProxy {
                    itemModel: dataModel
                    // Mapping model roles to surface series rows, columns, and values.
                    rowRole: "longitude"
                    columnRole: "latitude"
                    yPosRole: "elevation"
                }
            }
        }
        ListModel {
            id: dataModel
            ListElement{ longitude: "20"; latitude: "10"; elevation: "1000"; }
            ListElement{ longitude: "21"; latitude: "10"; elevation: "1200"; }
            ListElement{ longitude: "22"; latitude: "10"; elevation: "900"; }
            ListElement{ longitude: "23"; latitude: "10"; elevation: "1100"; }
            ListElement{ longitude: "20"; latitude: "11"; elevation: "1000"; }
            ListElement{ longitude: "21"; latitude: "11"; elevation: "1300"; }
            ListElement{ longitude: "22"; latitude: "11"; elevation: "1250"; }
            ListElement{ longitude: "23"; latitude: "11"; elevation: "1200"; }
            ListElement{ longitude: "20"; latitude: "12"; elevation: "1100"; }
            ListElement{ longitude: "21"; latitude: "12"; elevation: "1000"; }
            ListElement{ longitude: "22"; latitude: "12"; elevation: "950"; }
            ListElement{ longitude: "23"; latitude: "12"; elevation: "900"; }
            ListElement{ longitude: "20"; latitude: "13"; elevation: "850"; }
            ListElement{ longitude: "21"; latitude: "13"; elevation: "800"; }
            ListElement{ longitude: "22"; latitude: "13"; elevation: "750"; }
            ListElement{ longitude: "23"; latitude: "13"; elevation: "700"; }
        }
    }
}