CODEWITHSUNDEEP
qtqmlqt-quick
s4eed
s4eed

Reputation: 7891

How to expose a C++ Model to QML

I'm writing a QML+Qt application . I defined a class like this :

class MainClass : public QObject
{
    Q_OBJECT

public:
    rosterItemModel m_rosterItemModel;
.
.
.
}

rosterItemModel model is a class derived from QAbstractListModel. I exposed MainClass to qml part using this function :

qmlRegisterType<MainClass>("CPPIntegrate", 1, 0, "MainClass");

Now I want to assign this model(m_rosterItemModel) from MainClass to model property of a ListView in QML. I tried the following ways but none of them were helpful :(

Could someone help me?

Upvotes: 8

Views: 7949

Answers (1)

Frank Osterfeld
Frank Osterfeld

Reputation: 25165

There shouldn't be any metatype registration necessary. All you need to is to call setContextProperty and pass the model by pointer:

QQmlContext* context = view->rootContext(); //view is the QDeclarativeView
context->setContextProperty( "_rosterItemModel", &mainClassInstance->m_rosterItemModel );

Use it in QML:

model: _rosterItemModel

By pointer is important, as QObject's are not copy-constructible and copying them would break their semantics anyway (as they have an "identity").

The alternative to registering the model directly is to register your main class' instance and using Q_INVOKABLE. In MainClass:

Q_INVOKABLE RosterItemModel* rosterItemModel() const;

Registering an instance of mainClass (mainClassInstance again is assumed to be a pointer):

context->setContextProperty( "_mainInstance", mainClassInstance );

In QML:

model: _mainInstance.rosterItemModel()

Upvotes: 8

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