More complex example. Don't work

[Kuzma30]

I continue study QML and create more complex example, based on
https://forum.qt.io/topic/140468/periodically-update-data-in-qml-solved/4
I add new container class for hub(with 8 sensors).
hubset.h

#ifndef HUBSET_H
#define HUBSET_H

#include "hub.h"

class HubSet : public Hub
{
    Q_PROPERTY(QList<double> dataFromHubnumber READ dataFromHubnumber WRITE setDataFromHubnumber NOTIFY dataFromHubnumberChanged)
public:
    HubSet(Hub *currentHub);
    void addHub(int numberPos, Hub *currentHub);
    void removeHub(int numberPos);
    QList<double> dataFromHubnumber(int hubNumber);
    void setDataFromHubnumber(int hubNumber, QList<double> newData);
    int number_Of_Hub(void);
protected:
    QList<Hub *> m_hubset;
    int m_number_of_hub=0;
signals:
    void dataFromHubnumberChanged();
};

#endif // HUBSET_H

hubset.cpp

#include "hubset.h"

HubSet::HubSet(Hub *currentHub)
{
    m_hubset.append(currentHub);
    m_number_of_hub++;
}

void HubSet::addHub(int numberPos, Hub *currentHub)
{
    m_hubset.insert(numberPos, currentHub);
    m_number_of_hub++;
}
void HubSet::removeHub(int numberPos)
{
    m_hubset.removeAt(numberPos);
    m_number_of_hub--;
}
QList<double> HubSet::dataFromHubnumber(int hubNumber)
{
    return m_hubset[hubNumber]->channelData();
}
void HubSet::setDataFromHubnumber(int hubNumber, QList<double> newData)
{
    m_hubset[hubNumber]->setChannelData(newData);
}
int HubSet::number_Of_Hub(void)
{
    return m_number_of_hub;
}

I modify main.cpp . Now It create 5 set of sensors data. On C++ side it works fine.
main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlContext>
#include <QTimer>
#include <QtDebug>
#include <QRandomGenerator>
#include "Hub/hub.h"
#include "Hub/hubset.h"

#define numberOfHub 4

void setItem(QQmlApplicationEngine *pEngine);

HubSet tractor(new Hub);

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;

    for (int i=0;i<numberOfHub;i++)
    {
        tractor.addHub(i, new Hub);
    }
    engine.rootContext()->setContextProperty("tr", &tractor);

    engine.load(QUrl(QStringLiteral("qrc:/QML/main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    QTimer timer;
    QObject::connect(&timer, &QTimer::timeout, [&engine]() {
        setItem(&engine);
    });
    timer.start(5000);

    return app.exec();

}

void setItem(QQmlApplicationEngine *pEngine) {

    for (int i=0;i<tractor.number_Of_Hub();i++)
    {
        QList<double> temp;
        for (int j=0;j<8;j++)
        {
            temp.append(QRandomGenerator::global()->bounded(30, 120));
        }
        tractor.setDataFromHubnumber(i, temp);
        qDebug() << "Hub number " << i << ", last data = " << tractor.dataFromHubnumber(i);

    }
    qDebug() << "/**************************************************************/";
    qDebug() << "Number of Hub" << tractor.number_Of_Hub();
}

I see messages like this

Hub number  0 , last data =  QList(66, 67, 59, 97, 95, 97, 53, 52)
Hub number  1 , last data =  QList(93, 91, 89, 44, 39, 112, 76, 33)
Hub number  2 , last data =  QList(63, 92, 44, 74, 50, 69, 103, 64)
Hub number  3 , last data =  QList(41, 114, 118, 98, 68, 42, 67, 52)
Hub number  4 , last data =  QList(65, 96, 80, 110, 59, 45, 106, 34)
/**************************************************************/
Number of Hub 5
Hub number  0 , last data =  QList(92, 46, 95, 33, 61, 40, 114, 78)
Hub number  1 , last data =  QList(59, 52, 101, 94, 119, 56, 100, 44)
Hub number  2 , last data =  QList(101, 58, 60, 86, 31, 39, 68, 64)
Hub number  3 , last data =  QList(64, 43, 67, 50, 83, 106, 52, 77)
Hub number  4 , last data =  QList(114, 68, 98, 99, 42, 59, 87, 56)
/**************************************************************/
Number of Hub 5

On QML side I have problems
main.qml

import QtQuick 2.0
Window {
    id: root
    width: 400
    height: 150
    visible: true

    Rectangle {
        id: currentHub
        color: "green"
        border.color: Qt.lighter(color)
        anchors.fill: parent
        Row {
            height: currentHub.height
            width: currentHub.width
            Repeater {
                id: hub_id
                model: tr.dataFromHubnumber(0)//8
                Rectangle {
                    id: oneChartBar
                    anchors.bottom: parent.bottom
                    color: "red"
                    height: modelData //tr.dataFromHubnumber(0)[index]
                    width: currentHub.width/8
                    border.width: 1
                    border.color: Qt.lighter(color)
                    Text {
                        id: showchannel
                        anchors.horizontalCenter: oneChartBar.horizontalCenter
                        anchors.bottom: oneChartBar.bottom
                        text: qsTr("%1").arg(index+1)
                        color: "white"
                    }
                    Text {
                        id: showchanneldata
                        anchors.horizontalCenter: oneChartBar.horizontalCenter
                        anchors.top: oneChartBar.top
                        text: qsTr("%1").arg(oneChartBar.height)
                        color: "white"
                    }
                }
            }
        }
    }
}

In this example I want show sensors data (8 channels) of different hubs. I try to define model: tr.dataFromHubnumber(0)//8 and set height: modelData . This doesn't works. I get

qrc:/QML/main.qml:18: TypeError: Property 'dataFromHubnumber' of object Hub(0x5616d303c520) is not a function

When I use model :8 and height: tr.dataFromHubnumber(0)[index] I get

qrc:/QML/main.qml:23:21: TypeError: Property 'dataFromHubnumber' of object Hub(0x55e7826e7520) is not a function
qrc:/QML/main.qml:23:21: TypeError: Property 'dataFromHubnumber' of object Hub(0x55e7826e7520) is not a function
qrc:/QML/main.qml:23:21: TypeError: Property 'dataFromHubnumber' of object Hub(0x55e7826e7520) is not a function
qrc:/QML/main.qml:23:21: TypeError: Type error
qrc:/QML/main.qml:23:21: TypeError: Type error
qrc:/QML/main.qml:23:21: TypeError: Type error
qrc:/QML/main.qml:23:21: TypeError: Type error
qrc:/QML/main.qml:23:21: TypeError: Type error

On c++ side dataFromHubnumber(0) return QList <double> and theoretically can be use as model. What is a code for this situation?

[Bob64]

@Kuzma30 you need to mark methods that you want to access from QML as Q_INVOKABLE in your header file.

[Kuzma30]

@Bob64 said in More complex example. Don't work:

@Kuzma30 you need to mark methods that you want to access from QML as Q_INVOKABLE in your header file.

I add Q_INVOKABLE QList<double> dataFromHubnumber(int hubNumber); (in hubset.h)
But get same errors

qrc:/QML/main.qml:18: TypeError: Property 'dataFromHubnumber' of object Hub(0x55581f1b4520) is not a function

[jsulm]

@Kuzma30 said in More complex example. Don't work:

Q_INVOKABLE QList<double> dataFromHubnumber(int hubNumber);

Shouldn't it be

Q_INVOKABLE QList<double> setDataFromHubnumber(int hubNumber);

?

[Kuzma30]

I have 2 functions
QList<double> dataFromHubnumber(int hubNumber); // get latest data from specific Hub number (hubNumber)
void setDataFromHubnumber(int hubNumber, QList<double> newData); // set data newData to specific Hub number (hubNumber)
I use set-function on C++ side (to store random data) and get-function on QML side to show this data.

[Kuzma30]

I add Q_OBJECT (my mistake). Now I can use

model: tr.dataFromHubnumber(1)

for

Q_INVOKABLE QList<double> dataFromHubnumber(int hubNumber);

But it update date (function dataFromHubnumber ) only one time (at start);
I periodically add new data to QList

void setItem(QQmlApplicationEngine *pEngine) {

    for (int i=0;i<tractor.number_Of_Hub();i++)
    {
        QList<double> temp;
        for (int j=0;j<8;j++)
        {
            temp.append(QRandomGenerator::global()->bounded(30, 120));
        }
        tractor.setDataFromHubnumber(i, temp);
//        qDebug() << "Hub number " << i << ", last data = " << tractor.dataFromHubnumber(i);

    }
    qDebug() << "/**************************************************************/";
    qDebug() << "Number of Hub" << tractor.number_Of_Hub();
}

QList <double> HubSet::dataFromHubnumber(int hubNumber)
{
    qDebug() << " hubNumber = " << hubNumber << "channelData = " << m_hubset[hubNumber]->channelData();

    return m_hubset[hubNumber]->channelData();
}

void HubSet::setDataFromHubnumber(int hubNumber, QList<double> newData)
{
    m_hubset[hubNumber]->setChannelData(newData);
    emit dataFromHubnumberChanged();
}

            Repeater {
                id: hub_id
                model: tr.dataFromHubnumber(1)
                Rectangle {
                    id: oneChartBar
                    anchors.bottom: parent.bottom
                    color: "red"
                    height: modelData
                    width: currentHub.width/8
}

[Kuzma30]

There is latest code.
main.qml

import QtQuick 2.0

Window {
    id: root
    width: 400
    height: 150
    visible: true

    Rectangle {
        id: currentHub
        color: "green"
        border.color: Qt.lighter(color)
        anchors.fill: parent
        Row {
            height: currentHub.height
            width: currentHub.width
            Repeater {
                id: hub_id
                model: tr.dataFromHubnumber(1)
                Rectangle {
                    id: oneChartBar
                    anchors.bottom: parent.bottom
                    color: "red"
                    height: modelData
                    width: currentHub.width/8
                    border.width: 1
                    border.color: Qt.lighter(color)
                    Text {
                        id: showchannel
                        anchors.horizontalCenter: oneChartBar.horizontalCenter
                        anchors.bottom: oneChartBar.bottom
                        text: qsTr("%1").arg(index+1)
                        color: "white"
                    }
                    Text {
                        id: showchanneldata
                        anchors.horizontalCenter: oneChartBar.horizontalCenter
                        anchors.top: oneChartBar.top
                        text: qsTr("%1").arg(oneChartBar.height)
                        color: "white"
                    }
                }
            }
        }
        Timer {
            interval: 1000; running: true; repeat: true
            onTriggered:
            {
    //            ch.channelPrevDataChanged()
    //            ch.channelDataChanged()
    //            ch.channelStatusChanged()
    //            ch.barColorChanged()
//                tr.dataChanged()
                tr.dataFromHubnumberChanged()
            }
        }
    }
}

main.cpp

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlContext>
#include <QTimer>
#include <QtDebug>
#include <QRandomGenerator>
#include "Hub/hub.h"
#include "Hub/hubset.h"

#define numberOfHub 4

void setItem(QQmlApplicationEngine *pEngine);

HubSet tractor(new Hub);

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;

    for (int i=0;i<numberOfHub;i++)
    {
        tractor.addHub(i, new Hub);
    }
    engine.rootContext()->setContextProperty("tr", &tractor);

    engine.load(QUrl(QStringLiteral("qrc:/QML/main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    QTimer timer;
    QObject::connect(&timer, &QTimer::timeout, [&engine]() {
        setItem(&engine);
    });
    timer.start(1000);

    return app.exec();

}

void setItem(QQmlApplicationEngine *pEngine) {

    for (int i=0;i<tractor.number_Of_Hub();i++)
    {
        QList<double> temp;
        for (int j=0;j<8;j++)
        {
            temp.append(QRandomGenerator::global()->bounded(30, 120));
        }
        tractor.setDataFromHubnumber(i, temp);
//        qDebug() << "Hub number " << i << ", last data = " << tractor.dataFromHubnumber(i);

    }
    qDebug() << "/**************************************************************/";
    qDebug() << "Number of Hub" << tractor.number_Of_Hub();
}

hub.h

#ifndef Hub_H
#define Hub_H

#include <QObject>
#include <QMap>
#include <QDebug>

class Hub : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QList<double> channelData READ channelData WRITE setChannelData NOTIFY channelDataChanged)
public:
    explicit Hub(QObject *parent = nullptr)
    {
        m_channelData.append({1,2,3,4,5,6,7,8});
    }
    void setChannelData(QList<double> channelData)
    {
        m_channelData.append(channelData); //set current data value
        emit channelDataChanged();
    }

    QList<double> channelData()  // return current data list
    {
        return m_channelData.last();
    }
private:
    QList<QList<double>> m_channelData; // list of current datas
    int dataSize;
signals:
    void channelDataChanged();
};

#endif // Hub_H

hubset.h

#ifndef HUBSET_H
#define HUBSET_H

#include "hub.h"

class HubSet : public Hub
{
    Q_OBJECT
public:
    HubSet(Hub *currentHub);
    void addHub(int numberPos, Hub *currentHub);
    void removeHub(int numberPos);
    Q_INVOKABLE QList<double> dataFromHubnumber(int hubNumber);
    void setDataFromHubnumber(int hubNumber, QList<double> newData);
    int number_Of_Hub(void);
protected:
    QList<Hub *> m_hubset;
    int m_number_of_hub=0;
signals:
    void dataFromHubnumberChanged();
    void dataTestChanged();
private:
    QList<double> m_dataTest;
};

#endif // HUBSET_H

hubset.cpp

#include "hubset.h"

HubSet::HubSet(Hub *currentHub)
{
    m_hubset.append(currentHub);
    m_number_of_hub++;
}

void HubSet::addHub(int numberPos, Hub *currentHub)
{
    m_hubset.insert(numberPos, currentHub);
    m_number_of_hub++;
}
void HubSet::removeHub(int numberPos)
{
    m_hubset.removeAt(numberPos);
    m_number_of_hub--;
}

QList <double> HubSet::dataFromHubnumber(int hubNumber)
{
    qDebug() << " hubNumber = " << hubNumber << "channelData = " << m_hubset[hubNumber]->channelData();

    return m_hubset[hubNumber]->channelData();
}

void HubSet::setDataFromHubnumber(int hubNumber, QList<double> newData)
{
    m_hubset[hubNumber]->setChannelData(newData);
    emit dataFromHubnumberChanged();
}
int HubSet::number_Of_Hub(void)
{
    return m_number_of_hub;
}

I have (numberOfHub+1) sized data set of QList<double> (size = 8). I periodically add new data to the end of QList with setDataFromHubnumber(i, QList<double>) and want show on screen latest data. For this purpose I create function QList <double> HubSet::dataFromHubnumber(int hubNumber). I register class in QML
engine.rootContext()->setContextProperty("tr", &tractor);
When I run program it show only default values on screen and don't update with latest value.
For modeldata I use Q_INVOKABLE QList<double> dataFromHubnumber(int hubNumber) function.
When new data stored to the array I emit signal
emit dataFromHubnumberChanged();
But this not produce update data on the screen.
How to resolve this problem?

[kshegunov]

@Kuzma30 said in More complex example. Don't work:

I emit signal
emit dataFromHubnumberChanged();

You don't capture that signal from QML, so nothing should change. A QList is just that - a list of items, it doesn't know squat about changes, notifications and such.

But this not produce update data on the screen.
How to resolve this problem?

Write yourself a proper model would be the conventional advice.

[Kuzma30]

I change some data organization logic. And now I can show and update my charts. I show all channels in one chart (similar to
https://forum.qt.io/topic/140468/periodically-update-data-in-qml-solved/4, but model = numberOfHub*8)
After generating dates from all channel I update corresponded Hub.

void HubSet::setLatestChannelData(QList<double> newLatestChannelData)
{
    m_latestChannelData = newLatestChannelData;

    int j=0;
        QList<double>  temp_8_sized;
        for (int i = 0; i < 8*m_hubset.count(); ++i)
        {
            temp_8_sized.append(m_latestChannelData[i]);

            if (((i+1) % 8)==0)
            {
               m_hubset[j]->setChannelData(temp_8_sized);
               j++;
               temp_8_sized.clear();
            }
        }

    emit latestChannelDataChanged();
}
.....
protected:
    QList<Hub *> m_hubset;