Take the 2-minute tour ×
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free, no registration required.

According to Qt5 documentation: exposing methods including qt slots all public slots of C++ classes that inherit from QObject, are accessible from QML Here what I did:

C++

class MyClass : public QObject
{
    Q_OBJECT

public slots:
    void doStuffFromQmlSlot()
    {
        qDebug() << Q_FUNC_INFO;
    }

public:
    MyClass()
    {
        qDebug() << Q_FUNC_INFO;
    }
};

my main.cpp contains:

MyClass myClass;
QQmlEngine engine;
engine.rootContext()->setContextProperty( "myclass", &myClass );
QQmlComponent component( &engine, QUrl::fromLocalFile("qml/qtquick-01/main.qml") );
component.create();

QML

import QtQuick 2.0

Rectangle {
    width: 360
    height: 360
    Text {
        text: qsTr("Hello World")
        anchors.centerIn: parent
    }
    MouseArea {
        anchors.fill: parent
        onClicked: {
            myclass.doStuffFromQmlSlot();

            Qt.quit();
        }
    }
}

Actually the QtCreator seems to recognixe the exposed myclass object into the QML as it enables auto-completion of both class name (myclass) and the public slot doStuffFromQmlSlot(). When I run the application I unfortunately got the following error:

ReferenceError: myclass is not defined

Any clue on what I'm doing wrong?

share|improve this question
    
I posted on AskUbuntu as I found several questions regarding ubuntu-phone here. I agree that the topic is really programming specific, so the question is a good candidate for StackOverflow –  sergico Mar 11 at 16:29
1  
QML is a core progamming language for ubuntu & ubuntu-touch and hence is on-topic here, please re-open it. –  Sylvain Pineau Apr 12 at 12:31

1 Answer 1

up vote 4 down vote accepted

I reused your qml file to start a fresh project in QtCreator.

Please find below the files I used to compile and use the application successfully:

the project file: test.pro

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

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

HEADERS += myclass.h

myclass.h:

#include <QObject>
#include <qdebug.h>

class MyClass : public QObject
{
    Q_OBJECT

public slots:
    void doStuffFromQmlSlot()
    {
        qDebug() << Q_FUNC_INFO;
    }

public:
    MyClass()
    {
        qDebug() << Q_FUNC_INFO;
    }
};

main.cpp:

#include <QtGui/QGuiApplication>
#include "qtquick2applicationviewer.h"
#include <QQmlContext>
#include "myclass.h"

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

    QtQuick2ApplicationViewer viewer;
    viewer.rootContext()->setContextProperty("myclass", &myClass);
    viewer.setMainQmlFile(QStringLiteral("qml/main.qml"));
    viewer.showExpanded();

    return app.exec();
}

and qml/main.qml being exactly the snippet provided in your question

if you start the project using QtCreator you'll also have the qtquick2applicationviewer/ folder ready to be used. Then qmake && make && ./test will launch the application. If you click on the text element you'll get:

MyClass::MyClass() 
void MyClass::doStuffFromQmlSlot()
share|improve this answer
    
That worked! here what I was doing wrong: I was adding the classes to the wrong Context. Did not realized that the QtQuick2ApplicationViewer viewer is a QmlEngine as well. –  sergico Mar 9 at 9:52

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.