Issue While Using Repeater inside Repeater in Qml.

[hemang_1711]

Hello Everyone!
I have used two repeater model first one is for chart and second for series and thats are coming from graphmodel.cpp.
I am currently facing an issue with connecting a second model(SeriesRepeater Model) in main.qml file
I have written model.GraphParam in SeriesRepeater Model. It does not seem to link properly with backend. Any guidance on resolving this would be grateful. Thankyou!

Main.qml

import QtQuick
import QtQuick.Window
import QtQuick 6.2
import QtQuick.Controls 6.2
import QtQuick.Layouts 1.3
import QtCharts 2.5

Window {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    GridLayout {
        id: viewGridLayout
        anchors.fill: parent
        anchors.margins: 10
        columns: 2
        rows: 4
        columnSpacing: 10
        rowSpacing: 10
        flow: GridLayout.LeftToRight
        Layout.leftMargin: 3
        Layout.rightMargin: 0
        Layout.topMargin: 3
        Layout.bottomMargin: 3
        Repeater {
            id: chartRepeater
            model: monitoringScreen.graphModel
            Component.onCompleted: {
                console.log("chartRepeater", model, model.length)
                //                 Iterate over the model and print details of each item
                for (var i = 0; i < model.length; i++) {
                    var item = model[i]
                    console.log("Item", i, ":", JSON.stringify(item))
                }
            }

            delegate: ColumnLayout {
                id: chartRepeaterColumnLayout
                Layout.fillHeight: true
                Layout.fillWidth: true
                Layout.row: 0 + index
                Layout.column: 0
                spacing: 1

                Component.onCompleted: {
                    console.log("chartRepeaterColumnLayout", index,
                                model.GraphMaximumCount)
                }

                Repeater {
                    id: seriesRepeater
                    property int rowIndex: index
                    model: model.GraphParam
                    Component.onCompleted: {
                        console.log("seriesRepeater", index, model)
                    }
                    delegate: ChartViewWidget {
                        visible: true
                        paramTitle: "Hello"
                        yaxisMinValue: -5
                        yaxisMaxValue: 5
                        Component.onCompleted: {
                            console.log("ChartViewWidget", index)
                        }
                    }
                }
            }
        }
    }
}

ChartViewWidget.qml

import QtQuick 6.2
import QtQuick.Controls 6.2
import QtQuick.Layouts 1.3
import QtQuick.Controls.Universal 2.12
import Qt5Compat.GraphicalEffects
import QtQuick.Shapes 1.5
import QtCharts 2.15

RowLayout {
    id: chartviewRowLayout
    Layout.fillHeight: true
    Layout.fillWidth: true
    spacing: 0

    property alias paramTitle: paramTitleText.text
    property alias yaxisMinValue: yAxisLineSeries.min
    property alias yaxisMaxValue: yAxisLineSeries.max
    property alias chartWidget: chartType
    Rectangle {
        Layout.fillHeight: true
        Layout.minimumWidth: 50
        color: "#1d2027"
        Text {
            id: paramTitleText
            anchors.fill: parent
            color: "#048E93"
            horizontalAlignment: Text.AlignRight
            verticalAlignment: Text.AlignVCenter
            textFormat: Text.RichText
        }
    }
    Rectangle {
        Layout.fillHeight: true
        Layout.fillWidth: true
        color: "#1d2027"

        ChartView {
            id: chartType
            enabled: true
            smooth: true
            backgroundRoundness: 0
            legend.visible: false
            plotAreaColor: "#1d2027"
            backgroundColor: "#1d2027"
            margins.top: 0
            margins.bottom: 0
            margins.right: 3
            margins.left: 0
            anchors.fill: parent

            LineSeries {
                id: lineSeries
                axisX: xAxisLineSeries
                axisY: yAxisLineSeries
                color: "#048E93"
            }
            ValuesAxis {
                id: xAxisLineSeries
                min: 0
                max: 500
                gridVisible: false
                tickCount: 3
                visible: false
            }
            ValuesAxis {
                id: yAxisLineSeries
                min: -1
                max: 1
                gridVisible: false
                tickCount: 3
                labelsColor: "#999999"
            }
        }
    }
}

graphModel.h

#ifndef GRAPHMODEL_H
#define GRAPHMODEL_H

#include <QAbstractAxis>
#include <QAbstractListModel>
#include <QObject>
#include <QString>
#include <QXYSeries>
#include <QtCharts>

struct GraphWidgetParam {
    QString GraphTitle;
    QList<double> GraphData;
    double GraphDataValue;
    double yMin;
    double yMax;
    int CurrentIndex;
};

struct GraphModelItem {
    int MaximumCount;
    int CursorSize;
    QList<GraphWidgetParam*> GraphParam;
    int id;
};

class GraphModel : public QAbstractListModel {
    Q_OBJECT

    Q_PROPERTY(GraphWidgetParam* grWidget READ grWidget NOTIFY grWidgetChanged)

  public:
    enum GraphModelRole {

        GraphTitleRole = Qt::UserRole + 1,
        GraphPointRole,
        GraphMaximumCountRole,
        GraphCursorSizeRole,
        GraphListRole,

        ParameterId
    };
    Q_ENUM(GraphModelRole)

    //    Q_INVOKABLE GraphWidgetParam* getGraphParam(int index) const {
    //        if (index < 0 || index >= graphItems.count()) {
    //            return nullptr;
    //        }
    //        GraphModelItem parame;

    ////        GraphWidgetParam * pParam = m_Items[0].GraphParam.at(0);

    //        return parame.GraphParam.at(0); // Assuming you want the first GraphParam in the list
    //    }

    explicit GraphModel(QObject* parent = nullptr);

    int rowCount(const QModelIndex& parent = QModelIndex()) const override;

    QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override;

    QVector<GraphModelItem> m_Items;

    QHash<int, QByteArray> roleNames() const override;

    bool setData(const QModelIndex& index, const QVariant& value, int role) override;

    int getModelParameterIndex(int id);

    void updateParameterValuesOnModel(int id, GraphModelItem& item, const QString& valueStr);

    void startDataChange(void);

    void updateDataChange(void);

    void updateGraphData(int id, QList<int>& grData);

    void clearCharts(int paramId);

    void addNewGraphValue(int paramId, int colIndex, double value);

    void setGraphTitle(int paramId, const QString& title, int colIndex);

    GraphWidgetParam* grWidget();

    void appendRow(void);

    void endAppend(void);

    void AppendModel(GraphModelItem & item);

  public slots:
    void updateGraphSeriesDataFromIndex(int id, int seriesIndex, QAbstractSeries* series);

  signals:
    void updateGraphToUi(int index);
    void grWidgetChanged();

  private:
    static const QList<double> m_SampledData;
    int m_SampleIndex = 0;
    int m_index = 0;
    int m_TotalCount = 0;
    int cursorSize = 5;

    qreal qMultiplier = 1;

    GraphWidgetParam m_GraphWidgetParam;

    QList<GraphModelItem*> graphItems;
};

#endif // GRAPHMODEL_H

graphmodel.cpp

#include "graphmodel.h"
GraphModel::GraphModel(QObject* parent)
        : QAbstractListModel(parent) {
}

int GraphModel::rowCount(const QModelIndex& parent) const {
    if (parent.isValid())
        return 0;
    return m_Items.size();
}

QVariant GraphModel::data(const QModelIndex& index, int role) const {
    if (!index.isValid())
        return QVariant();
    if (index.row() < 0 || index.row() >= m_Items.size()) {
        return QVariant();
    }

    switch (role) {
    case GraphMaximumCountRole:
        return QVariant(m_Items.at(index.row()).MaximumCount);
    case GraphCursorSizeRole:
        return QVariant(m_Items.at(index.row()).CursorSize);
    case GraphListRole:
        return QVariant::fromValue(m_Items.at(index.row()).GraphParam[0]);

        //        return QVariantConstPointer(m_Items.at(index.row()).GraphParam[0]);
        //        return QVariant(m_Items.at(index.row()).GraphParam[0]);

    case ParameterId:
        return QVariant(m_Items.at(index.row()).id);
    default:
        return QVariant();
    }
}

QHash<int, QByteArray> GraphModel::roleNames() const {
    QHash<int, QByteArray> names;

    names[GraphTitleRole] = "GraphTitle";
    names[GraphMaximumCountRole] = "GraphMaximumCount";
    names[GraphCursorSizeRole] = "GraphCursorSize";
    names[GraphListRole] = "GraphList";
    names[ParameterId] = "id";

    return names;
}

bool GraphModel::setData(const QModelIndex& index, const QVariant& value, int role) {
    int row = index.row();
    bool isValid = false;

    qDebug() << Q_FUNC_INFO;
    if (row >= 0 && row < m_Items.size()) {
        switch (role) {
        case ParameterId:
            if (m_Items[row].id != value.toInt()) {
                m_Items[row].id = value.toInt();
                isValid = true;
            }
            break;

        case GraphMaximumCountRole:
            if (m_Items[row].MaximumCount != value.toInt()) {
                m_Items[row].MaximumCount = value.toInt();
                isValid = true;
            }
            break;
        case GraphCursorSizeRole:
            if (m_Items[row].CursorSize != value.toInt()) {
                m_Items[row].CursorSize = value.toInt();
                isValid = true;
            }
            break;

        case GraphListRole:
            qDebug() << Q_FUNC_INFO << "GraphListRole" << row << value.toInt();
            if (m_Items[row].GraphParam.size() != value.toInt()) {
                m_Items[row].GraphParam.clear();
                for (int i = 0; i < value.toInt(); i++) {
                    GraphWidgetParam* localGrWidget = new GraphWidgetParam;
                    m_Items[row].GraphParam.append(localGrWidget);
                }
                isValid = true;
            }
            break;

        default:
            break;
        }

        if (isValid == true)
            emit dataChanged(index, index, QVector<int>() << role);
    }

    return true;
}

void GraphModel::setGraphTitle(int paramId, const QString& title, int colIndex) {
    int row = getModelParameterIndex(paramId);

    if (row >= 0 && row < m_Items.size()) {
        if (colIndex >= 0 && colIndex < m_Items[row].GraphParam.size()) {
            GraphWidgetParam* pParam = m_Items[row].GraphParam.at(colIndex);
            if (pParam->GraphTitle != title) {
                pParam->GraphTitle = title;
            }
        }
    }
}

void GraphModel::addNewGraphValue(int paramId, int colIndex, double value) {
    int row = getModelParameterIndex(paramId);

    if (row >= 0 && row < m_Items.size()) {
        if (colIndex >= 0 && colIndex < m_Items[row].GraphParam.size()) {
            GraphWidgetParam* pParam = m_Items[row].GraphParam.at(colIndex);
            pParam->GraphDataValue = value;
        }
    }
}

void GraphModel::clearCharts(int paramId) {
    int row = getModelParameterIndex(paramId);
    if (row >= 0 && row < m_Items.size()) {
        m_Items[row].GraphParam.clear();
    }
}

int GraphModel::getModelParameterIndex(int id) {
    if (m_Items.size()) {
        for (int i = 0; i < m_Items.size(); i++) {
            if (m_Items.at(i).id == id) {
                return i;
            }
        }
    }
    return -1;
}


void GraphModel::appendRow(void) {
    int rows = rowCount();
    beginInsertRows(QModelIndex(), rows, rows);
}

void GraphModel::endAppend(void) {
    endInsertRows();
}

void GraphModel::AppendModel(GraphModelItem & item) {
    appendRow();
    m_Items.append(item);
    endAppend();
}

void GraphModel::startDataChange(void) {
    beginResetModel();
}

void GraphModel::updateDataChange(void) {
    endResetModel();
}

void GraphModel::updateGraphSeriesDataFromIndex(int id, int seriesIndex, QAbstractSeries* series) {
    if (series == nullptr)
        return;

    QXYSeries* xySeries = static_cast<QXYSeries*>(series);

    if (xySeries == nullptr)
        return;

    qreal x(0);
    qreal y(0);

    int row = getModelParameterIndex(id);

    x = xySeries->count();
    m_TotalCount = m_Items.at(row).MaximumCount;

    qDebug() << "Total Count" << m_TotalCount;

    GraphWidgetParam* pParam = m_Items[row].GraphParam.at(seriesIndex);

    y = pParam->GraphDataValue;

    if (m_SampleIndex < (m_TotalCount - 4)) {
        m_SampleIndex += 2;
    } else {
        m_SampleIndex = 0;
    }

    if (xySeries->count() < m_TotalCount) {
        xySeries->append(x, y);
        qDebug() << "x:y:" << x << y;
        //        qDebug() << "XY Point count:" << xySeries->count();
    } else {
        if ((m_index <= (m_TotalCount - cursorSize))) {
            xySeries->removePoints(m_index, cursorSize);

            xySeries->insert(m_index, QPointF(m_index, y));
            xySeries->insert(m_index + 1, QPointF(m_index + 1, 0));
            xySeries->insert(m_index + 2, QPointF(m_index + 2, 0));
            xySeries->insert(m_index + 3, QPointF(m_index + 3, 0));
            xySeries->insert(m_index + 4, QPointF(m_index + 4, 0));

            QList<QPointF> points1 = xySeries->points();

            points1[m_index + 1].setY(NAN);
            points1[m_index + 2].setY(NAN);
            points1[m_index + 3].setY(NAN);
            points1[m_index + 4].setY(NAN);

            xySeries->replace(points1);
        }

        if ((m_index < (m_TotalCount - 1))) {
            m_index++;
        } else {
            m_index = 0 + 1;
            qMultiplier++;

            if (qMultiplier > 5) {
                qMultiplier = 1;
            }
        }
    }

    double yMin = pParam->yMin;
    double yMax = pParam->yMax;
    if (y > yMax) {
        yMax = y;
        yMax = yMax + (yMax * 0.3);

    }
    if (y < yMin) {
        yMin = y;
        yMin = yMin + (yMin * 0.3);
        yMin = yMin - yMax;
    }
}

void GraphModel::updateGraphData(int id, QList<int>& grData) {
    int row = -1;

    row = getModelParameterIndex(id);

    qDebug() << Q_FUNC_INFO << id << row;

    if (row != -1) {

        emit updateGraphToUi(row);
    }
}

GraphWidgetParam* GraphModel::grWidget(void) {

    GraphWidgetParam* pParam = m_Items[0].GraphParam.at(0);
    return pParam;
}

MonitoringScreen.cpp

#include "monitoringscreen.h"
#include "graphmodel.h"

MonitoringScreen::MonitoringScreen(QObject *parent)
    : QObject{parent}
{

    m_GraphModel = new GraphModel(this);

    initMonitoringGraph(1,2);
    initMonitoringGraph(2,1);
    initMonitoringGraph(3,2);
}


MonitoringScreen::~MonitoringScreen() {
    delete m_GraphModel;
}


void MonitoringScreen::initMonitoringGraph(int ParamType, int ChildGraph) {

    GraphModelItem item;

    item.id = ParamType;

    item.MaximumCount = ChildGraph;
    for (int i = 0; i < ChildGraph; i++) {
        GraphWidgetParam* localGrWidget = new GraphWidgetParam;
        item.GraphParam.append(localGrWidget);
    }

    m_GraphModel->AppendModel(item);
}

GraphModel *MonitoringScreen::graphModel() const
{
    return m_GraphModel;
}

[Bob64]

@hemang_1711 said in Issue While Using Repeater inside Repeater in Qml.:

                ...
                id: seriesRepeater
                property int rowIndex: index
                model: model.GraphParam
                ...

In model.GraphParam what is model and how is GraphParam exposed from it (and what is it)?

[hemang_1711]

@Bob64 Thanks for replying...

• As I have mentioned I am using Repeater inside Repeater its chartviewrepeater model. thats why I am using model.GraphParam (monitoringScreen.graphModel.GraphParam).
• GraphParam is pointer of GraphWidgetParam structure which is availale in graphmodel.h.
• There is initMonitoringGraph fun in monitoringscreen.cpp I am using graphmodel here.

[Bob64]

@hemang_1711 thanks. My apologies if I missed anything but there is quite a lot of code to navigate through.

Firstly, I am not sure whether the QML scoping rules allow you refer to model from chartRepeater when model from seriesRepeater is in scope.

It might be better to specify the RHS explicitly at least to rule out any issue.

Secondly, although I now see that GraphParam is a member of GraphModelItem, it is not clear to me that GraphModelItem has been exposed to QML. Again, apologies if I have missed something. (Also, I guess there might be other code that hasn't been shown.)

[hemang_1711]

@Bob64
As you said "QML scoping rules allow you refer to model from chartRepeater when model from seriesRepeater is in scope." And About Series model I print in Console window onComponent.on Completed.
There is monitoringscreen.h i not provided.

monitoringscreen.h

#ifndef MONITORINGSCREEN_H
#define MONITORINGSCREEN_H

#include <QObject>
#include "graphmodel.h"

class MonitoringScreen : public QObject
{
    Q_OBJECT

    Q_PROPERTY(GraphModel* graphModel READ graphModel NOTIFY graphModelChanged)

public:
    explicit MonitoringScreen(QObject *parent = nullptr);
    ~MonitoringScreen();
    GraphModel *graphModel() const;

signals:
    void graphModelChanged();

private:
    void initMonitoringGraph(int ParamType, int ChildGraph);
    GraphModel *m_GraphModel = nullptr;
};

#endif // MONITORINGSCREEN_H

[Bob64]

@hemang_1711 I am not sure why it is not working for you. If I were you I would try to cut it down to the smallest example possible (no need to involve charts or anything) to investigate how to get a nested model to work. I am reasonably sure it is possible because I have seen people discuss it, but I have looked through my own code and have never needed to do this. I might try to make a simple project myself.

[Bob64]

@hemang_1711 I have just gone back to your original post and I see again what originally confused me.

If you recall, I asked about GraphParam, which you are trying to access in your QML. I looked for this in your model implementation, but your model does not have a role "GraphParam".

You do have a role "GraphList", which seems to return the first element of the list member named GraphParam in the GraphModelItem struct in your implementation. Although GraphParam is the name of the struct member, QML does not know anything about this name. It only sees the names you have defined in your roles.

[hemang_1711]

The issue was solved Add child model in parent repeater's Compoenet.onCompleted.

Repeater {
                id: repeater1
                model: backend.graphModel
                Component.onCompleted: {
                    repeater2.model = model.GraphMaximumCount
                }
            }
            Repeater {
                id: repeater2
}