Using C++ with QML

[bobweaver]

Hello there and thanks for taking the time to look at this post. :)

I want to use some c++ code that I have hacked away at in QML

bonjourbrowser.h
@
#ifndef BONJOURBACKEND_h
#define BONJOURBACKEND_h
#include <QString>
#include <QTcpSocket>
#include "bonjourrecord.h"

class BonjourServiceBrowser;
class BonjourServiceResolver;
class QHostInfo;
class BonjourBackend : public QObject

{
Q_OBJECT
public slots:
void updateString(const QList<BonjourRecord> &list);
public:
BonjourBackend(QObject *parent = 0);

private:
quint16 blockSize;
BonjourServiceBrowser *bonjourBrowser;
BonjourServiceResolver *bonjourResolver;
};
#endif
@

bonjourbackend,cpp

@
#include <QtNetwork>
#include "bonjourbackend.h"
#include "bonjourservicebrowser.h"
#include "bonjourserviceresolver.h"

BonjourBackend::BonjourBackend(QObject *parent)
: QObject(parent), bonjourResolver(0)
{
BonjourServiceBrowser *bonjourBrowser = new BonjourServiceBrowser(this);
setenv("AVAHI_COMPAT_NOWARN","1",1);
connect(bonjourBrowser, SIGNAL(currentBonjourRecordsChanged(const QList<BonjourRecord> &)),
this, SLOT(updateString(const QList<BonjourRecord> &)));
bonjourBrowser->browseForServiceType(QLatin1String("_mythbackend-master._tcp"));
}
void BonjourBackend::updateString(const QList<BonjourRecord> &list)
{
QString backend;
foreach (BonjourRecord record, list) {
backend.append(record.serviceName);
qDebug() << backend;
}
}
@

main.cpp

@
#include "bonjourserviceresolver.h"
#include "bonjourservicebrowser.h"
#include "bonjourbackend.h"
#include "bonjourrecord.h"

int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QtQuick2ApplicationViewer viewer;
viewer.setMainQmlFile(QStringLiteral("qml/Mythbuntu-QML/main.qml"));
viewer.showExpanded();
viewer.show();

BonjourBackend updateString;
viewer.rootContext()->setContextProperty("backend",&updateString);
return app.exec();
}
@

The CPP runs great and returns the string that I am looking for but the QML on the other hand does not
qml/Mythbuntu-QML/main.qml

@
import QtQuick 2.0
import QtQuick.XmlListModel 2.0
import QtQuick.Particles 2.0
import QtQuick.LocalStorage 2.0
import QtQuick.Window 2.0
import Qt.labs.folderlistmodel 2.0
import "common"
import "common/models"
import "common/dbUtil.js" as DataBase
import "common/Util.js" as Util
import "common/Remote.js" as Remote
Rectangle{
id: root
............
.......................
..........................
.................................

    Text{
        id: tname
        width: Screen.width / 20
        height:    Screen.height / 20
        color: Qt.darker("orange", 1.5)
        text:{
           var q =  backend
            return q.toString()
        } //drives + "\n" +   appThemePath+DataBase.theme()
        anchors{
            left:  themeRec.left
            top: themeRec.top
        }
    }

......................................
................................................
.............................................................
....................................................................
MouseArea{
anchors.fill: mythImage
onClicked: {
var q = backend.toString()
console.log(q)
}
}
}
.............
....................
.
...........................
}
@

Here is a the output from qDebug ()the one that I want in QML in the end
@
"Mythbackend on ubuntu"
"Mythbackend on ubuntu"
@

and here is what I get with Mouse area and what not in QML
@
BonjourBackend(0xbfd46488)
@

Thanks again for taking the time to look this over and I look forward to solving this, Thanks

[sierdzio]

Your backend object does not contain "toString" method, as far as I can see. Add it as a slot or Q_INVOKABLE and it should work.

[portoist]

Calling toString on object in QML prints out type info about object. You should define property using Q_PROPERTY macro, or method using Q_INVOKABLE macro in your C++ backend and then use this in QML. Maybe you should take a look at this "doc":http://qt-project.org/doc/qt-5.0/qtqml/qtqml-cppintegration-definetypes.html .

[bobweaver]

thanks all I was able to fix it with your and some IRC help. I am very new to the fourms and would like to say thanks you made me feel welcomed .