How to access C++ enum from QML?

Question

class StyleClass : public QObject {
public:
    typedef enum
        {
            STYLE_RADIAL,
            STYLE_ENVELOPE,
            STYLE_FILLED
        }  Styl         


        

Answer 1

As of Qt 5.8 you can expose enums from a namespace:

Define the namespace and enum:

#include <QObject>

namespace MyNamespace
{
    Q_NAMESPACE         // required for meta object creation
    enum EnStyle {
        STYLE_RADIAL,
        STYLE_ENVELOPE,
        STYLE_FILLED
    };
    Q_ENUM_NS(EnStyle)  // register the enum in meta object data
}

Register the namespace (eg. in main(), before creating a Qml View/Context):

qmlRegisterUncreatableMetaObject(
  MyNamespace::staticMetaObject, // static meta object
  "my.namespace",                // import statement (can be any string)
  1, 0,                          // major and minor version of the import
  "MyNamespace",                 // name in QML (does not have to match C++ name)
  "Error: only enums"            // error in case someone tries to create a MyNamespace object
);

Use it in a QML file:

import QtQuick 2.0
import my.namespace 1.0

Item {
    Component.onCompleted: console.log(MyNamespace.STYLE_RADIAL)
}

References:

https://www.kdab.com/new-qt-5-8-meta-object-support-namespaces/

http://doc.qt.io/qt-5/qqmlengine.html#qmlRegisterUncreatableMetaObject

http://doc.qt.io/qt-5/qobject.html#Q_ENUM_NS