QT Quick Application Window embed C++ object - c++

Question

I have a QT Quick 2.2 ApplicationWindow and I want to use inside this ApplicationWindow a C++ object.
I know QQuickView view, but this work only for objects which are derived from QQuickItem (not for ApplicationWindow).
I also know qmlRegisterType, but this adds only a general C++ class in QML. I want only to have one C++ object (instantiated in C++ code) in the ApplicationWindow.
Is there a possibility to use a C++ Object in a QT Quick 2.2 ApplicationWindow?
main.cpp
#include <QApplication>
#include <QQmlApplicationEngine>
#include <QQuickView>
#include <QQmlContext>
#include "myclass.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
MyClass myClass;
QQmlApplicationEngine engine;
engine.load(QUrl(QStringLiteral("qrc:///main.qml")));
return app.exec();
}
myclass.h
#include <QObject>
#include <QString>
class MyClass : public QObject
{
Q_OBJECT
public:
MyClass(QObject *parent = 0) {};
Q_INVOKABLE QString getValue();
};
myclass.cpp
#include "myclass.h"
#include <QString>
QString MyClass::getValue() {
return "42";
}
qrc:///main.qml
import QtQuick 2.2
import QtQuick.Controls 1.1
ApplicationWindow {
visible: true
Text {
text: myClass.getValue()
anchors.centerIn: parent
}
}
Thanks

Answer 1

It depends or your purpose. If you want to define QML type from C++, you should do this in your main.cpp for example :
qmlRegisterType< MyClass >("com.example.myclass", 1, 0, "MyClass");
now in your .qml file, first you need to import your newly created data type using import statement :
import com.example.myclass 1.0
and then you can create an item from your own data type:
import QtQuick 2.2
import QtQuick.Controls 1.1
import com.example.myclass 1.0
ApplicationWindow {
visible: true
Text {
text: myClass.getValue()
anchors.centerIn: parent
}
MyClass {
}
}
But you have another solution. You can pass a QObject object from c++ to QML.
QQmlApplicationEngine engine;
engine.rootContext()->setContextProperty("myClass", new MyClass);
engine.load(QUrl(QStringLiteral("qrc:///main.qml")));
Now inside of your qml file you can access myClass object.