Calling c++ function from qml

rockstar

i am using qt creator......

actually till yesterday i was doing programs only using qml.....this is my first project using both cpp and qml ......

i thought it was easy but it's not.......

lgeyer

It actually is easy.

Please don't get me wrong - but I have told you for the third time now how it is supposed to be done and how to circumvent the need of including generated files and I still sense that you do not even properly read what I write.
@
// testclass.h

class TestClass : public QObject
{
Q_OBJECT

public:
TestClass(QObject *parent = 0);

Q_INVOKABLE QString returnString();

};

// testclass.cpp

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

QString TestClass::returnString()
{
return "string";
}

// main.cpp

int main(int argc, char *argv[])
{
QApplication application(argc, argv);

QDeclarativeView view;

view.rootContext()->setContextProperty("TestClass", new TestClass(&view));
view.setSource(QUrl::fromLocalFile&#40;"Test.qml"&#41;);
view.show();

return application.exec&#40;&#41;;

}

// Test.qml

import QtQuick 1.1

Text {
text: TestClass.returnString()
}
@

rockstar

thanks a ton Lukas.....it worked....

mathiii

Hey guys,

I´m having exactly the same problem, but I think some of the Classes and Libraries have changed. The way Lukas explained this makes a lot of sense to me, but the code doesn´t work for me. I´m using Qt 5.3 with QtQuick 2.2 .
I would be very thankful if someone could look at my code, as I´m desperate at the moment.My goal is to write a String into an xml-file.
the c++function should be called from qml.

Thanks in advance

@
//header.h
class TestClass : public QObject
{
Q_OBJECT

public:
TestClass(QObject *parent = 0);

Q_INVOKABLE void writeXml(QString &text){ }

};@

@//func.cpp

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

void TestClass::writeXml(QString text)
{

        QString filename = "C:/Qt5/Tools/QtCreator/bin/CPPTEST2/example.xml";
        QFile file&#40;filename&#41;;
        if (file.open(QIODevice::ReadWrite)) {
            QTextStream stream(&file);
            stream << text << endl;
             }
        file.close();

}@

@
//main.cpp
{
QGuiApplication app(argc, argv);

QQmlApplicationEngine engine;
engine.load(QUrl(QStringLiteral("qrc:///main.qml")));
QQuickView *view = new QQuickView;
view->setSource(QUrl::fromLocalFile&#40;"qrc:///main.qml"&#41;);
view->show();

return app.exec();

}
@
@ //main.qml
import QtQuick 2.2
import QtQuick.Window 2.1

Window {
visible: true
width: 360
height: 360

MouseArea {
    anchors.fill: parent
    onClicked: {
        TestClass.writeXml("Hello World");
    }
}

}@

messi

Hi mathiii
this is not how it works.
You have to create a C++ object first.
Than make the object for QML visible.
Now you can access the object.

Check out the following link.
It describes every C++/QML interaction:
http://qt-project.org/wiki/Introduction_to_Qt_Quick_for_Cpp_developers#e70ea8482b12de725ec779f1bc55c92c

Best regards