multiple Q_ENUM_NS in one namespace OK?

mzimmers

Hi all -

This is what I'm trying to do:

// equipmentitem.h
namespace EquipmentNS {
Q_NAMESPACE
    enum Category {
        ...
    };
    Q_ENUM_NS(Category)
    enum PowerState {
        POWER_OFF,
        POWER_ON
    };
    Q_ENUM_NS(PowerState)
}
...
// main.cpp
    // register the Equipment state enums so they can be used in QML.
    qmlRegisterUncreatableMetaObject(
        EquipmentNS::staticMetaObject, // meta object created by Q_NAMESPACE macro
        "equipmentNS",                // import statement (can be any string)
        1, 0,                           // major and minor version of the import
        "EquipmentNS",                    // name used in QML (does not have to match C++ name)
        "Error: only enums"             // error in case someone tries to create an object
        );

A few questions:

~~is this legal?~~ dumb question; disregard.
is this correct?
is this complete?
is this a bad idea?
how do I reference the respective enums in QML? I'd have expected it to be something like this:

EquipmentNS.POWER_ON

But that gives me an undefined error.

Thanks...

mzimmers

The answer is "yes," it works. I had some mistakes in my attempt which caused me to question it, but it works fine when you do it right.

In simplest terms (credit to this post):

// header file of your choice
namespace EquipmentNS {
Q_NAMESPACE
    enum Category {
        ...
    };
    Q_ENUM_NS(Category)
    enum PowerState {
        POWER_OFF,
        POWER_ON
    };
    Q_ENUM_NS(PowerState)
}

// main.cpp
qmlRegisterUncreatableMetaObject(
    EquipmentNS::staticMetaObject, // meta object created by Q_NAMESPACE macro
    "equipment.enums",                // used in qml import statement
    1, 0,                           // major and minor version of the import
    "EquipmentNS",                    // name used in QML (does not have to match C++ name)
    "Error: only enums"             // error in case someone tries to create an object
    );

// your qml file
import equipment.enums // same as 2nd argument in call to qmlRegisterUncreatableMetaObject().
...
console.log(EquipmentNS.POWER_ON)

MikePooh

Yes. It works. However you won't be able to have same enum names since one will shadows another one.

namespace EquipmentNS {
Q_NAMESPACE
    enum Category {
        POWER_OFF = 100,
        ...
    };
    Q_ENUM_NS(Category)
    enum PowerState {
        POWER_OFF, #Here value 0 will shadow value 100
        POWER_ON
    };
    Q_ENUM_NS(PowerState)
}