Call C++ function from QML

YEAHYEAH

Hi

I followed this example (http://qt-project.org/doc/qt-5.0/qtqml/qtqml-cppintegration-exposecppattributes.html) but I can't make it run.

Can someone provide me a complete example of how call a c++ function from qml 2 (source code: cpp, qml, pro ).

Thanks in advance.

p3c0

Hi,

Although there are lot of example's related to this, here's a super simple example which call cpp function from QML on mouse click.

hellocpp.h

@
#ifndef HELLOCPP_H
#define HELLOCPP_H

#include <QObject>

class HelloCpp : public QObject
{
Q_OBJECT
public:
explicit HelloCpp(QObject *parent = 0);
Q_INVOKABLE void printMessage(QString txt);

signals:

public slots:

};

#endif // HELLOCPP_H
@

hellocpp.cpp

@
#include "hellocpp.h"
#include <QDebug>

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

void HelloCpp::printMessage(QString txt)
{
qDebug() << "Message from QML: " << txt;
}
@

main.qml

@
import QtQuick 2.0
import HelloCpp 1.0

Rectangle {
width: 360
height: 360

HelloCpp {
    id: demo
}

Text {
    text: qsTr("Hello World")
    anchors.centerIn: parent
}
MouseArea {
    anchors.fill: parent
    onClicked: {
        demo.printMessage("Hello Cpp. Nice to see you");
    }
}

}
@

main.cpp

@
#include <QtGui/QGuiApplication>
#include <QtQuick>
#include "qtquick2applicationviewer.h"
#include "hellocpp.h"

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

qmlRegisterType<HelloCpp>("HelloCpp", 1, 0, "HelloCpp");

QtQuick2ApplicationViewer viewer;
viewer.setMainQmlFile&#40;QStringLiteral("qml/QMLTest/main.qml"&#41;);
viewer.showExpanded();

return app.exec();

}
@

Just go through the code starting from main.cpp. Create a default QtQuick example from QtCreator and copy the above code to it.

The explanation for the functions like qmlRegisterType and Q_INVOKABLE are already nicely documented. Please refer docs for more details.

YEAHYEAH

Thanks p3c0, your example runs like a charm.

:D