Custom model in c ++ doesnt update ListView on QML side - c++

Question

I'm building GUI to control my ADC, connected to the STM32 board. Communications are handled by UART. Everything works fine. The problem is to properly handling my custom channel structure as a model object to be able to present data in different ways depending on the delegate object.
I have tried a few different solutions, none of them works. The case looks trivial however is a little different than presented examples on the forum or in tutorials on the web because I'm trying to update the data model from c++ side, not from qml. That forces me to invoke setData() override method to be invoked on c++ side and propagate dataChange() signal into qml. Let's present some code.
That's how the app presents the data models after initialization. This data are provided in SensorList constructor. No matter what I tried, I can not change those values on qml side. Even when I confirmed using debugger that vector of my channels in sensorList is changing when data are received from sensor. This looks like a problem with communication between C++ and QML.
My data handler.
ADS8588h.h
#ifndef CHANNEL_H
#define CHANNEL_H
#include <QObject>
#include <QString>
class AdsChannel {
Q_GADGET
Q_PROPERTY(QString name READ name )
Q_PROPERTY(double value READ value )
public:
AdsChannel(const QString& channelName, const double value)
: mName{channelName}, mValue{value} {}
AdsChannel() = default;
AdsChannel(const AdsChannel& rhs) = default;
AdsChannel& operator=(const AdsChannel& rhs) = default;
void setName(const QString& name) { mName = name;}
void setValue(const double value) { mValue = value; }
const QString name() const { return mName; }
double value() const { return mValue; }
private:
QString mName;
double mValue;
};
Q_DECLARE_METATYPE(AdsChannel);
#endif // CHANNEL_H
SensorList.h which collects list of channels
#ifndef SENSORLIST_H
#define SENSORLIST_H
#include "AdsChannel.h"
class SensorList : public QObject
{
Q_OBJECT
public:
explicit SensorList(QObject *parent = nullptr)
{
mItems.push_back(AdsChannel("CH1",5.0));
mItems.push_back(AdsChannel("CH2",55.0));
mItems.push_back(AdsChannel("CH3",0.0));
mItems.push_back(AdsChannel("CH4",0.0));
mItems.push_back(AdsChannel("CH5",0.0));
mItems.push_back(AdsChannel("CH6",0.0));
mItems.push_back(AdsChannel("CH7",0.0));
mItems.push_back(AdsChannel("CH8",0.0));
}
QVector<AdsChannel> items() const
{
return mItems;
}
bool setItemAt(int index, const AdsChannel &item)
{
if (index < 0 || index >= mItems.size())
return false;
const AdsChannel &oldItem = mItems.at(index);
if (item.name() == oldItem.name() && item.value() == oldItem.value())
return false;
mItems[index] = item;
return true;
}
private:
QVector<AdsChannel> mItems;
};
#endif // SENSORLIST_H
SensorDataModel.h
#ifndef SENSORDATAMODEL_H
#define SENSORDATAMODEL_H
#include <QAbstractListModel>
#include <QStandardItemModel>
#include "AdsChannel.h"
#include "SensorList.h"
class SensorList;
class SensorDataModel : public QAbstractListModel
{
Q_OBJECT
Q_PROPERTY(SensorList *list READ list WRITE setList)
public:
explicit SensorDataModel(QObject *parent = nullptr);
enum {
NameRole = Qt::UserRole +1 ,
ValueRole
};
// Basic functionality:
int rowCount(const QModelIndex &parent = QModelIndex()) const override;
QVariant data(const QModelIndex &index, int role = ValueRole) const override;
// Editable:
bool setData(const QModelIndex &index, const QVariant &value,
const int role = ValueRole) override;
Qt::ItemFlags flags(const QModelIndex& index) const override;
virtual QHash<int, QByteArray> roleNames() const override;
SensorList *list() const;
void setList(SensorList *list);
private:
SensorList *mList;
};
#endif // SENSORDATAMODEL_H
SensorDataModel.cpp
#include "SensorDataModel.h"
#include "SensorList.h"
SensorDataModel::SensorDataModel(QObject *parent)
: QAbstractListModel(parent)
, mList(new SensorList)
{
}
int SensorDataModel::rowCount(const QModelIndex &parent) const
{
// For list models only the root node (an invalid parent) should return the list's size. For all
// other (valid) parents, rowCount() should return 0 so that it does not become a tree model.
if (parent.isValid() || !mList)
return 0;
return mList->items().size();
}
QVariant SensorDataModel::data(const QModelIndex &index, int role) const
{
if (!index.isValid() || !mList)
return QVariant();
const AdsChannel item = mList->items().at(index.row());
switch (role) {
case NameRole:
return QVariant(item.name());
case ValueRole:
return QVariant(item.value());
}
return QVariant();
}
bool SensorDataModel::setData(const QModelIndex &indexModel, const QVariant &value,const int role)
{
// indexModel is empty as this method is invocable from c++ side. Index which is given in dataChange() signal is calculated
// based on index data which are updated
//When data arrived from a sensor this how this method is invoked.
//mData.setData(QModelIndex(),QVariant::fromValue<AdsChannel>(temp),SensorDataModel::ValueRole);
if (!mList)
return false;
auto newElement = value.value<AdsChannel>();
const auto listElements = mList->items();
AdsChannel item;
int indexFinder = 0;
for(indexFinder ; indexFinder < rowCount(); ++indexFinder)
{
if(newElement.name() == listElements.at(indexFinder).name()) {
item = listElements.at(indexFinder);
break;
}
}
switch (role) {
case NameRole:
item.setName(newElement.name());
break;
case ValueRole:
item.setValue(newElement.value());
break;
}
if (mList->setItemAt(indexFinder, item)) {
emit dataChanged (this->index(indexFinder,0), this->index(indexFinder,0), QVector<int>() << role);
//This signal is emited but never reached on QML side
return true;
}
return false;
}
Qt::ItemFlags SensorDataModel::flags(const QModelIndex &index) const
{
if (!index.isValid())
return Qt::NoItemFlags;
return Qt::ItemIsEditable;
}
QHash<int, QByteArray> SensorDataModel::roleNames() const
{
QHash<int, QByteArray> names;
names[NameRole] = "channelName";
names[ValueRole] = "value";
return names;
}
SensorList *SensorDataModel::list() const
{
return mList;
}
void SensorDataModel::setList(SensorList *list)
{
// I never use a setList() as my list is initialized throw constructor.
beginResetModel();
if (mList)
mList->disconnect(this);
mList = list;
endResetModel();
}
main.cpp
#include "ads8588h.h"
#include "SensorList.h"
#include "SensorDataModel.h"
int main(int argc, char *argv[]) {
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QGuiApplication app(argc, argv);
ADS8588H driver ;
qmlRegisterType<ADS8588H>("AdsDriver", 1, 0, "AdsDriver"); // Used to some other features
qmlRegisterType<SensorDataModel>("SensorModel", 1, 0, "SensorDataModel");
qmlRegisterUncreatableType<SensorList>("SensorModel", 1, 0, "SensorList",
QStringLiteral("SensorList should not be created in QML"));
QQmlApplicationEngine engine;
engine.rootContext()->setContextProperty(QStringLiteral("sensorList"), driver.getSensor()->list());
const QUrl url(QStringLiteral("qrc:/main.qml"));
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();
}
QML code using simple TEXT label to eliminate some potential bug using CANVAS, requestPaint() signals and other.
import QtQuick 2.0
import QtQuick.Layouts 1.3
import QtQuick.Controls 2.3
import SensorModel 1.0
Item {
id:root
anchors.fill: parent
ListView {
implicitWidth: root.width * 0.8
implicitHeight: width
x:root.width/2 - width/2
y:170
id: customList
focus: true
spacing: 4
snapMode: ListView.SnapOneItem
highlightRangeMode: ListView.StrictlyEnforceRange
highlightMoveDuration: 250
orientation: ListView.Vertical
boundsBehavior: Flickable.StopAtBounds
model: SensorDataModel{
list: sensorList
onDataChanged: console.log("ss") //<-- This signal never appear
}
delegate: Item{
width: parent.width
height: width * 0.2
// ChannelProgressBar{
// id:licznik
// anchors.fill: parent
// labelSuffix: suffix
// labelChannel: model.channelName
// progressValue: model.value
// }
Row{
spacing: 20
Text{
id:label1
font.pixelSize: 40
text: model.channelName
}
Text{
id:label2
font.pixelSize: 40
text: model.value
}
}
}
}
}
So my question is What im doing wrong that qml did not updated data even when dataChanged() signal is emitted.