QList<QObject*> as member that can be used as a list

fcarney

Okay, I have been playing around with using QList<QObject*> as a member of an object that acts like a list model in QML. This works and I can get to the custom properties defined in my SubObject that derives from QObject.

Q_PROPERTY(QList<QObject*> subList READ subList NOTIFY subListChanged)

However, when I try to use an object that inherits QObject I cannot use that object as a list:

Q_PROPERTY(QList<SubObject*> subList READ subList NOTIFY subListChanged)

I tried registering this SubObject class using:

Q_DECLARE_METATYPE
qmlRegisterType<SubObject>(); 
qRegisterMetaType<QList<SubObject*>>();

but I cannot get QML to recoqnize a new list type to use in a ListView as a model. The methods and properties seem to still work that define on the custom SubObject.

Is QList<QObject*> just special?

ODБOï

hi,
@fcarney said in QList<QObject*> as member that can be used as a list:

However, when I try to use an object that inherits QObject I cannot use that object as a list:

you can pass your SubObjects to QML as QVariantList and use it as list model

Q_PROPERTY(QVariantList selectedPrograms READ selectedPrograms NOTIFY selectedProgramsChanged)

   QVariantList selectedPrograms(){
       QVariantList progList;
       for(auto prg : m_selectedPrograms){
           progList.append(QVariant::fromValue(prg));
       }
       return progList;
   }

private :
 QList<Job*> m_selectedPrograms;

fcarney

@LeLev said in QList<QObject*> as member that can be used as a list:

you can pass your SubObjects to QML as QVariantList and use it as list model

Holy crap that was a lot easier than what I was trying. I looked all over for this and never found something this simple. I have been looking for a light weight list type for QML that was not based on the abstract list models. This is perfect!

Thanks.

ODБOï

@fcarney I'm glad it helped

GrecKo

@LeLev said in QList<QObject*> as member that can be used as a list:

you can pass your SubObject to QML as QVariantList and use it as list model

How is that better than a QObjectList?

fcarney

@GrecKo said in QList<QObject*> as member that can be used as a list:

How is that better than a QObjectList?

I think QObjectList is just a QList<QObject*> alias from what I read. I think internally the QVariant is probably just seeing my SubObject* as QObject*. But you can add non-qobject based types with Q_DECLARE_METATYPE. So QVariant version would be able to handle that.

GrecKo

Yes QObjectList is just a QList<QObject*>, but in your case, QVariantList is just adding another level of indirection.

If you don't mind using a 3rd party library and a bit more intrusive solution, you can use : QQmlObjectListModel from http://gitlab.unique-conception.org/qt-qml-tricks/qt-qml-models .

It behaves as a QList<T*> on the c++ side but also expose a QAIM (QAbstractItemModel) interface emitting the correct signals so you can plug a QML view onto it.

As for your original question, yes QList<QObject*> is specially handled by QML views.

ODБOï

@GrecKo said in QList<QObject*> as member that can be used as a list:

How is that better than a QObjectList?

i don't know, tell me