C++ Model to QML ChartView - Not Showing Anything

[Sajjad Ali]

Hello, I tried to make a C++ model. Then put it to ChartView in QML. Graph is not showing anything. I can't find anything related example online. Pls help me identify what I am doing wrong.

main.cpp

#include <QApplication>
#include <QQmlApplicationEngine>
#include "DataModel.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QQmlApplicationEngine engine;

    DataModel MyModel;
    qmlRegisterSingletonInstance ("hello.com",1,0,"MyData",&MyModel);

    const QUrl url(u"qrc:/CPPModelForChart/main.qml"_qs);
    QObject::connect(
        &engine,
        &QQmlApplicationEngine::objectCreated,
        &app,
        [url](QObject *obj, const QUrl &objUrl) {
            if (!obj && url == objUrl)
                QCoreApplication::exit(-1);
        },
        Qt::QueuedConnection);
    engine.load(url);

    return app.exec();
}

DataModel.h

#ifndef DATAMODEL_H
#define DATAMODEL_H

#include <QObject>
#include <QAbstractTableModel>
#include <QList>
#include <QPointF>

class DataModel : public QAbstractTableModel
{
    Q_OBJECT
public:
    enum {
        ValueRole = Qt::DisplayRole
    };
    explicit DataModel(QObject *parent = nullptr);
    int rowCount(const QModelIndex &parent) const;
    int columnCount(const QModelIndex &parent) const;
    QVariant data(const QModelIndex &index, int role) const;
    QHash<int, QByteArray> roleNames() const;

signals:

private:
    QList <QPointF> m_points;
};

#endif // DATAMODEL_H

DataModel.cpp

#include "DataModel.h"

DataModel::DataModel(QObject *parent)
    : QAbstractTableModel{parent}
{
    m_points << QPointF(0, 0) << QPointF(1, 1) << QPointF(2, 4);
}

int DataModel::rowCount(const QModelIndex &parent) const
{
    return m_points.size();
}

int DataModel::columnCount(const QModelIndex &parent) const
{
    return 2;
}

QVariant DataModel::data(const QModelIndex &index, int role) const
{
    if (!index.isValid() || role != Qt::DisplayRole)
        return QVariant();

    const QPointF p = m_points[index.row()];

    if (index.column() == 0)
        return p.x();

    return p.y();
}

QHash<int, QByteArray> DataModel::roleNames() const
{
    QHash<int, QByteArray> mappings;
    mappings [ValueRole] = "value";
    return mappings;
}

main.qml

import QtQuick
import QtCharts
import hello.com as Peter

Window {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")
    // Write chartview that can take model from c++
    ChartView {
        id: dataChartView
        animationOptions: ChartView.NoAnimation
        antialiasing: true
        anchors.fill: parent

        ValuesAxis {
            id: axisXdata
            min: 0
            max: 3
        }

        ValuesAxis {
            id: axisYdata
            min: 0
            max: 5
        }

        LineSeries {
            id: dataLineSeries
            name: "Data"
            axisX: axisXdata
            axisY: axisYdata
            useOpenGL: true
        }

        VXYModelMapper {
            id: dataModelMapper
            model: Peter.MyData
            series: dataLineSeries
            firstRow: 0
            xColumn: 0
            yColumn: 1
        }
    }
}

[Sajjad Ali]

Update: I don't know why. It works when I remove OpenGL stuff from QML file.