/home/user/workspace-test/qt5app/
├── build-qt5app-qt5-Debug
│   ├── main.o
│   ├── Makefile
│   ├── moc_myapplication.cpp
│   ├── moc_myapplication.o
│   ├── moc_myobject.cpp
│   ├── moc_myobject.o
│   ├── moc_qtquick2applicationviewer.cpp
│   ├── moc_qtquick2applicationviewer.o
│   ├── myapplication.o
│   ├── qml
│   │   └── qt5app
│   │       └── main.qml
│   ├── qt5app
│   └── qtquick2applicationviewer.o
├── main.cpp
├── myobject.cpp
├── myobject.h
├── qml
│   └── qt5app
│       └── main.qml
├── qt5app64.png
├── qt5app80.png
├── qt5app.desktop
├── qt5app_harmattan.desktop
├── qt5app.pro
├── qt5app.pro.user
└── qtquick2applicationviewer
    ├── qtquick2applicationviewer.cpp
    ├── qtquick2applicationviewer.h
    └── qtquick2applicationviewer.pri




//qt5app.pro
# Add more folders to ship with the application, here
folder_01.source = qml/qt5app
folder_01.target = qml
DEPLOYMENTFOLDERS = folder_01

# Additional import path used to resolve QML modules in Creator's code model
QML_IMPORT_PATH =

# If your application uses the Qt Mobility libraries, uncomment the following
# lines and add the respective components to the MOBILITY variable.
# CONFIG += mobility
# MOBILITY +=

# The .cpp file which was generated for your project. Feel free to hack it.
SOURCES += main.cpp \
    myobject.cpp

# Installation path
# target.path =

# Please do not modify the following two lines. Required for deployment.
include(qtquick2applicationviewer/qtquick2applicationviewer.pri)
qtcAddDeployment()

HEADERS += \
    myobject.h



//myobject.h
#ifndef MYOBJECT_H
#define MYOBJECT_H

#include <QObject>
#include <QDebug>
#include <QQmlComponent>
#include <QQmlEngine>

class MyObject : public QObject
{
    Q_OBJECT
public:
    explicit MyObject(QObject *parent = 0);
    ~MyObject(void) {}
    QObject *object;
    QQmlComponent *component;

    void loadComponent(void);
signals:

public slots:
    void continueLoading();

private:
    QQmlEngine _engine;
};

#endif // MYOBJECT_H


//myobject.cpp
#include <iostream>
#include "myobject.h"

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

void MyObject::loadComponent(void)
{
    QQmlComponent *component = new QQmlComponent(&_engine);
    component->loadUrl(QStringLiteral("qml/qt5app/main.qml"));

    if(!component->isReady()){
        qWarning("qPrintable: %s", qPrintable(component->errorString()));
    }

    if (component->isLoading()){
        std::cout <<"==== component->isLoading ====";
        QObject::connect(component,
                         SIGNAL(statusChanged()),
                         this,
                         SLOT(continueLoading()));
    }
    else{
        std::cout <<"==== component is not Loading ====";
        continueLoading();
    }
}

void MyObject::continueLoading()
{
    QQmlComponent *component = new QQmlComponent(&_engine);
    component->loadUrl(QStringLiteral("qml/qt5app/main.qml"));

    if (component->isError()) {
        qWarning() << "component->isError()="<< component->errors();
    } else {
        object = component->create();
        std::cout <<"object created";
    }
}

//main.qml
import QtQuick 2.0

Rectangle {
   width: 360
   height: 360
   function myQmlFunction(msg_cpp) {
       console.log("Got msg_cpp:", msg_cpp)
       return "output"
   }
}

//main.cpp
#include <QtGui/QGuiApplication>
#include "qtquick2applicationviewer.h"
#include <QtQuick/QQuickItem>
#include <QtQuick/QQuickView>
#include <QQmlEngine>
#include <QtQml>
#include <QtCore>
#include <QtQuick/QtQuick>
#include <QQmlComponent>
#include <QtQml/qqml.h>
#include "myobject.h"

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

    QtQuick2ApplicationViewer viewer;
    viewer.setMainQmlFile(QStringLiteral("qml/qt5app/main.qml"));

    MyObject *myClass = new MyObject();
    myClass->loadComponent();

    QObject *object=myClass->object;
    qDebug() << "step 1";

    QVariant returnedValue;
    QVariant msg_cpp = "C++ message";
    QMetaObject::invokeMethod(object,
                              "myQmlFunction",
                              Q_RETURN_ARG(QVariant, returnedValue),
                              Q_ARG(QVariant, msg_cpp));
    qDebug() << "step 2";

    qDebug() << "Got QML return:" << returnedValue.toString();

    viewer.showExpanded();
    object->deleteLater();
    return app.exec();
}