qmlflags

main.cpp

#include <QDebug>
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QQmlContext>

class Foo : public QObject {
    Q_OBJECT
public:
    enum Ability {
        NONE = 0,
        RETRY = 1 << 0,
        CANCEL = 1 << 1,
        SHOW_PROGRESS = 1 << 2,
    };
    Q_DECLARE_FLAGS(Abilities, Ability)
    Q_FLAG(Abilities)

    Q_INVOKABLE void echoFlags(Abilities flags)
    {
        qDebug() << "flags" << flags;
    }
};

class Bar : public QObject {
    Q_OBJECT
public:
    Q_INVOKABLE void echoFlags(Foo::Abilities flags)
    {
        qDebug() << "flags from bar" << flags;
    }
};

#include "main.moc"

int main(int argc, char* argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

    QGuiApplication app(argc, argv);

    qmlRegisterType<Foo>("foo", 1, 0, "Foo");
    qmlRegisterType<Bar>("foo", 1, 0, "Bar");

    Foo foo;
    Bar bar;
    QQmlApplicationEngine engine;
    engine.rootContext()->setContextProperty("foo", &foo);
    engine.rootContext()->setContextProperty("bar", &bar);
    engine.load(QUrl(QStringLiteral("./main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    return app.exec();
}

main.qml

import QtQuick 2.9
import QtQuick.Controls 2.2
import QtQuick.Window 2.2
import foo 1.0

ApplicationWindow {
    id: window
    visible: true
    width: 640
    height: 480
    title: qsTr("Stack")

    Button {
        anchors.centerIn: parent
        onClicked: {
            foo.echoFlags(Foo.RETRY | Foo.CANCEL);
            bar.echoFlags(Foo.RETRY | Foo.CANCEL);
        }
    }
}