metaenumtest.cpp

//
// Sometimes QML still surprise by really just doing the right thing.
// For instance the following lines:
//
//      console.info("Status:", Status.Unknown, Status.Good, Status.Warning, Status.Failing);
//      console.info("Sensor:", Sensor.Unknown, Sensor.Good, Sensor.Warning, Sensor.Failing);
//
// really print:
//
//      qml: Status: 0 1 2 3
//      qml: Sensor: 0 1 2 3
//
// eventhough there is no meta enum for Unknown in Sensor.
// It just does smartly because the property most likely needs it.
//

#include <QCoreApplication>
#include <QQmlComponent>
#include <QQmlEngine>

namespace SharedEnumTest {

class Status
{
    Q_GADGET

public:
    enum Value { Unknown, Good, Warning, Failing };
    Q_ENUM(Value)
};

class Sensor : public QObject
{
    Q_OBJECT
    Q_PROPERTY(SharedEnumTest::Status::Value status MEMBER m_status CONSTANT FINAL)

public:
    using QObject::QObject;
    ~Sensor() override = default;

private:
    Status::Value m_status = Status::Unknown;
};

} // namespace SharedEnumTest

int main(int argc, char *argv[])
{
    QCoreApplication app{argc, argv};

    qmlRegisterType<SharedEnumTest::Sensor>("SharedEnumTest", 1, 0, "Sensor");
    qmlRegisterUncreatableType<SharedEnumTest::Status>("SharedEnumTest", 1, 0, "Status", "Gadgets cannot be instantiated in QML");

    const QByteArray qml = R"(
        import SharedEnumTest 1.0

        import QtQml 2.2

        QtObject {
            Component.onCompleted: {
                console.info("Status:", Status.Unknown, Status.Good, Status.Warning, Status.Failing);
                console.info("Sensor:", Sensor.Unknown, Sensor.Good, Sensor.Warning, Sensor.Failing);
            }
        }
    )";

    QQmlEngine engine;
    QQmlComponent test{&engine};
    test.setData(qml, {});
    test.create();

    return EXIT_SUCCESS;
}

#include "main.moc"