Qt 5.5 (beta): Custom value types in QML

[Peter K]

One of the new features of Qt5.5 is the ability to expose custom value types to QML from C++, supposedly similar to Qt.vector3d, Qt.point, etc.

Is there any documentation or example available that explains how to do this? E.g. how do I write such a value type in C++ and how do I expose it to QML?

[richardo]

Have a look at https://doc-snapshots.qt.io/qt5-dev/qobject.html#Q_GADGET

You can simply write your plain struct just by adding the macro.

struct MyStruct {
     QPROPERTY(QString name MEMBER m_name)
     Q_GADGET;
     QString m_name;
}

Than you can convert it to a QJSValue by simply calling this function: https://doc-snapshots.qt.io/qt5-dev/qjsengine.html#toScriptValue

  MyStruct instance { "the name" };
  QJSValue value = engine.toScriptValue(instance);

Or you may just return it in a already registered QObject via Q_INVOKABLE or as QPROPERTY.

[Peter K]

Thanks for your response richardo. That looks remarkably simple. I will experiment with it later.