Connections qml dial and slider in qml - c++

Question

I have a dial and a slider, in mainwindow.cpp I have:
ui->quickWidget_3->setSource(QUrl("qrc:///slider.qml"));
ui->quickWidget_4->setSource(QUrl("qrc:///dial.qml"));
I want that when I move slider dial moves..
I wrote:
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtQml>
#include <QtQuick>
#include <QSlider>
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
setStyleSheet("background-color:white");
ui->quickWidget->engine()->rootContext()->setContextProperty("yourObject",ui->horizontalSlider);
ui->quickWidget_2->engine()->rootContext()->setContextProperty("yourObject1",ui->horizontalSlider_3);
QObject* item = ui->quickWidget_3->rootObject();
QObject::connect(item, SIGNAL(moved()), SLOT(sliderMoved()));
ui->quickWidget_2->setSource(QUrl("qrc:///sl.qml"));
ui->quickWidget->setSource(QUrl("qrc:///qml.qml"));
ui->quickWidget_3->setSource(QUrl("qrc:///slider.qml"));
ui->quickWidget_4->setSource(QUrl("qrc:///dial.qml"));
ui->horizontalSlider->setStyleSheet("QSlider::groove:vertical {background-color:red; position:absolute; left:4px; right: 4px}");
//connect circularGauge e text
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::on_horizontalSlider_2_sliderMoved(int position)
{
ui->dial->setValue(position);
}
void MainWindow::sliderMoved()
{
QObject* slider = ui->quickWidget_3->rootObject();
QObject* dial = ui->quickWidget_4->rootObject();
qreal value = QQmlProperty::read(slider, "value").toReal();
QQmlProperty::write(dial, "value", value);
}
but it doesn't work

Answer 1

It is well documented here: Interacting with QML Objects from C++
Please try to provide full relevant working code in your questions next time, like I'm going to do in this answer. Doing so, you will increase the chance of an answer.
test.pro
QT += core gui widgets quickwidgets quickcontrols2
[...]
dial.qml
import QtQuick.Controls 2.12
Dial {
id: control
from: 0
to: 100
stepSize: 1
value: 0
}
slider.qml
import QtQuick.Controls 2.12
Slider {
id: control
from: 0
to: 100
stepSize: 1
value: 0
}
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();
public slots:
void sliderMoved();
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
mainwindow.cpp
#include <QQmlProperty>
#include <QQuickItem>
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
ui->quickWidget_1->setSource(QUrl("qrc:/slider.qml"));
ui->quickWidget_2->setSource(QUrl("qrc:/dial.qml"));
QObject* item = ui->quickWidget_1->rootObject();
QObject::connect(item, SIGNAL(moved()), SLOT(sliderMoved()));
}
void MainWindow::sliderMoved()
{
QObject* slider = ui->quickWidget_1->rootObject();
QObject* dial = ui->quickWidget_2->rootObject();
qreal value = QQmlProperty::read(slider, "value").toReal();
QQmlProperty::write(dial, "value", value);
}
MainWindow::~MainWindow()
{
delete ui;
}