Fail To Connect Qml signal to C++ Slot - c++

Question

I have been trying to connect signal between Qml file and c++, but public slot in c++ doesn't seem to receive the signal.
What might be wrong with my program?
main.qml
Item{
id:item
signal qml_signal
Button{
onClicked: {
item.qml_signal();
}
}
}
main.cpp
QQuickView view(QUrl("qrc:/main.qml"));
QObject *item = view.rootObject();
Myclass myclass;
QObject::connect(item, SIGNAL(qml_signal()), &myclass,SLOT(cppSlot()));
myclass.h
void cppSlot() ;
myclass.cpp
void Myclass::cppSlot(){
qDebug() << "Called the C++ slot with message:";
}

Answer 1

When you want objects to interact between C++ and QML, you must do it on the QML side, since obtaining a QML object from C++ can cause you many problems, as in this case, the signal created in QML can not be handled in C++.
The solution is to export your object myclass to QML and make the connection there:
main.cpp
#include "myclass.h"
#include <QGuiApplication>
#include <QQuickView>
#include <QQmlContext>
int main(int argc, char *argv[])
{
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QGuiApplication app(argc, argv);
QQuickView view(QUrl("qrc:/main.qml"));
Myclass myclass;
view.rootContext()->setContextProperty("myclass", &myclass);
view.show();
return app.exec();
}
main.qml
import QtQuick 2.9
import QtQuick.Controls 1.4
Item{
id:item
signal qml_signal
Button{
onClicked: item.qml_signal()
}
onQml_signal: myclass.cppSlot()
}