Error while setting QQmlApplicationEngine ->rootContext()->setContextProperty

Slash200

Hello,

I'm setting a ContextProperty for a QQmlApplicationEngine and getting a this error:

C:\Qt\5.10.0\mingw53_32\include\QtCore\qmetatype.h:1377: Fehler: 'QObject' is an inaccessible base of 'DataSourceObject'
         enum { Value = sizeof(checkType(static_cast<T*>(Q_NULLPTR))) == sizeof(yes_type) };

C:\Qt\5.10.0\mingw53_32\include\QtCore\qglobal.h:756: Fehler: static assertion failed: Type is not registered, please use the Q_DECLARE_METATYPE macro to make it known to Qt's meta-object system
 #define Q_STATIC_ASSERT_X(Condition, Message) static_assert(bool(Condition), Message)

My Code:

#include "connect.h"
#include "updreceiver.h"
#include "datasourceobject.h"
#include <QDebug>
#include <QQmlContext>
#include <QQmlApplicationEngine>


Connect::Connect(QObject *parent) : QObject(parent)
{
    //Create connection to QML Application
    QQmlApplicationEngine *engine = dynamic_cast<QQmlApplicationEngine*>( parent );
    if (engine == Q_NULLPTR) return;

     m_UpdReceiver = new UpdReceiver();
    //this Object contains all datasources as Object! Definition in datasourceobject.h!
    auto m_datasourcelist = m_UpdReceiver->initDataSources();


    //Link m_datasourcelist to Model on QML side
    engine->rootContext()->setContextProperty("dataSourceModel", QVariant::fromValue(m_datasourcelist));

    //m_UpdReceiver starts now to listen to incoming UDP packages
    m_UpdReceiver->startUdpReceiver();

}

m_datasourcelist is from type QList<DataSourceObject*>

DataSourceObject is a class which should store values for a Datamodel for QML.

regards
Bastian

SGaist

Hi,

As the error suggest you have to register your custom type.

dheerendra

Inaddition to @SGaist, DataSourceObject is it inherited from QObject ? Also how did you declare QList ? Can you show the declaration ?

Slash200

@dheerendra
this is the declaration of the list:

QList<DataSourceObject*> m_DataSourceList;

And this the header of the DataSourceObject:

#ifndef DATASOURCEOBJECT_H
#define DATASOURCEOBJECT_H

#include <QObject>

class DataSourceObject : QObject
{
    Q_OBJECT

    Q_PROPERTY(int id READ id WRITE setid NOTIFY idChanged)
    Q_PROPERTY(QString name READ name WRITE setname NOTIFY nameChanged)
    Q_PROPERTY(QString displayname READ displayname WRITE setdisplayname NOTIFY displaynameChanged)

public:

    //Constructors and destructors
    DataSourceObject();
    DataSourceObject(int id, QString name, QString displayname){
        m_id = id;
        m_name = name;
        m_displayname = displayname;
    }
    DataSourceObject(const DataSourceObject&); //copy constructor
    ~DataSourceObject()=default;

    void setid(int id){
        m_id = id;
    }

    int id() const{
        return m_id;
    }

    void setname(QString name){
        m_name = name;
    }

    QString name() const{
        return m_name;
    }

    void setdisplayname(QString displayname){
        m_displayname = displayname;
    }

    QString displayname() const{
        return m_displayname;
    }

signals:

    void idChanged(int id);
    void nameChanged(QString name);
    void displaynameChanged(QString displayname);

private:

    int m_id;
    QString m_name;
    QString m_displayname;

};

Q_DECLARE_METATYPE(DataSourceObject);


#endif // DATASOURCEOBJECT_H

dheerendra

Have you registered the DataSourceObject using qmlRegisterMetaType(..) in main or somewhere ?

Slash200

I found the problem.
In the class definition I had

class DataSourceObject : QObject

instead of

class DataSourceObject : public QObject

Now registering with qmlRegisterType is working