Adding and localizing menu items in the main menu of a Qt application menubar

Question

So first of all here is a screenshot of the said menu of Evernote, localized in French:

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As you can see, all the menu items in the main menu (by main menu I mean the one whose name is the application name, like here it is Evernote) are localized in French. There are lots of menu items which the Evernote app itself brings, like Évaluez Evernote pour Mac (Rate Evernote for Mac), Information du compte... (Account Info...), etc. Plus there are the standard OS X provided menu items like Quit Evernote, Preferences, etc which are also localized.

My questions:

1. How do I add a new item in this main menu? How to access this menu to add items?
2. How do I localize these items based on my app localization, both OS X provided default ones and the ones I add?
3. In the Evernote menu, everything seems to be localized except the Services menu option (the submenu options are however localized!)? Can't this be localized as well?

What I have tried:

fMenuBar = fMainWindow->menuBar();
fMenuFile = fMenuBar->addMenu(QObject::tr(qPrintable(String_Class::FileMenu))); //"File" in English, translated into other languages
fAboutAppAct = new QAction(QObject::tr(qPrintable(String_Class::About_App)), fMainWindow); //prints "About App", localized in all languages
fMenuFile->addAction(fAboutAppAct);
fAboutAppAct->setMenuRole(QAction::AboutRole); //otherwise it sits with the other file menu options in the File menu

//reset UI language slot, called whenver UI language is reset. It retranslates all strings in all menus, except this
void AppMenu::reTranslateUISlot()
{
    fAboutAppAct->setText(QObject::tr(qPrintable(String_Class::About_App))); 
}

Answer 1

Maybe you could reimplement in MainWindow or in AppMenu the changeEvent.

void MainWindow::changeEvent(QEvent *event)
{
    if (event->type() == QEvent::LanguageChange) {
        this->retranslateUi(this);
        quickStart->retranslateUi(quickStart);
        //etc...
    } else {
        QMainWindow::changeEvent(event);
    }
}

You could force Widgets to retranslate themselves. But you need to have registered some QTranslator first.

For example, in the constructor of MainWindow (or in some config dialog) if it's possible to change language at runtime (what I've done in my software):

CustomizeOptionsDialog::CustomizeOptionsDialog(QWidget *parent)
    : QDialog(parent, Qt::Tool)
{
    // Load the language of the application
    customTranslator.load(languages.value( SettingsPrivate::instance()->language()) );

    // Translate standard buttons (OK, Cancel, ...)
    defaultQtTranslator.load("qt_" + SettingsPrivate::instance()->language(), QLibraryInfo::location(QLibraryInfo::TranslationsPath));
    QApplication::installTranslator(&customTranslator);
    QApplication::installTranslator(&defaultQtTranslator);
}

Where language() returns "fr", "gb" or "cs" (initialized from a signal emitted when one has chosen a new language in options).

/** Change language at runtime. */
void CustomizeOptionsDialog::changeLanguage(const QString &language)
{
    QString lang = languages.value(language);
    SettingsPrivate *settings = SettingsPrivate::instance();

    // If the language is successfully loaded, tells every widget that they need to be redisplayed
    if (!lang.isEmpty() && lang != settings->language() && customTranslator.load(lang)) {
        settings->setLanguage(language);
        defaultQtTranslator.load("qt_" + lang, QLibraryInfo::location(QLibraryInfo::TranslationsPath));
        QApplication::installTranslator(&customTranslator);
        /// TODO: reload plugin UI
        QApplication::installTranslator(&defaultQtTranslator);
    } else {
        labelStatusLanguage->setText(tr("No translation is available for this language :("));
    }
}

I hope it's helping.

Answer 2

I still haven't found the complete answer to my problems. But here some of the observations I have made over the last few days:

1. To be able to add menu items in the main menu, you have to set the menu role accordingly, i.e after adding it wherever you want to (it won't matter, because it will move out), you set the menu role like this:

   fYourAction->setMenuRole(QAction::ApplicationSpecificRole);
   

This will add the menu item in the main menu. If you add more than item in this way, they will appear in the order in which you set their menu roles.

2. There are few specific roles Qt already provides - i.e for the About <app> item, Quit <app> item, Preferences... item, etc. They are mentioned here. For example, if your action has a text "Foo", and you add it somewhere as a menu item, and set the role like

   fFooAction->setMenuRole(QAction:: PreferencesRole);
   

then it will automatically move to the main menu and show as Preferences..., what text you actually put in the action will be immaterial. Whatever slot you have attached to it as a response to the triggered() signal will still fire correctly, though. Same goes for QAction::AboutRole as well, whatever text you add in that action, it will move to the main menu and show as About <your_app_name>.

3. The problem with QAction::AboutRole or QAction:: PreferencesRole is like I said, they won't localize even if you try. They will get localized only when the system locale changes, if you change it just within your app by installing a new translator, it won't change. The workaround? Avoid them and use QAction::ApplicationSpecificRole for all items you want to appear in the main menu. Then they will get properly localized as per your custom translator, and will respect whatever text you provide in the action, i.e if you give foo as text in the action, it will appear as foo in the main menu, and get localized accordingly. Again, mind you, when you are adding multiple items, set the role of the items in order of their appearance, i.e to simulate the Evernote menu above, first set the menu role for the about_app action, then the preferences action. Where you are adding them will be of no importance since they will be moved to a new menu, so the order in which you set the menu role for the items will determine the order in which they appear in the main menu.

4. The problem with the above approach is that I don't know how to insert separators between the items I am adding in the main menu. It is easy to do that in the menus we add, since we have access to the menu object, but here we don't have access (we add the items somewhere else, and make them move to the main menu by setting the menu role), so I don't know yet how to add multiple separators in the main menu.