QLocale detects system language incorrectly on Windows with language pack installed - windows

Question

I am attempting to detect current system language with QLocale:
QLocale::Language sysLangId = QLocale::system().language();
However, it's not working correctly. I'm on Russian Windows 7 with English language pack applied, but language() returns Russian instead of English. Is there any workaround?

Answer 1

When I was working on Localization in Qt, I used
QString locale = QLocale::system().name();
When I tested getting the locale, I found it was dependent on the Format in the Region and Language settings:
Control Panel > Region and Language > Format
Hope that helps.

Answer 2

I've found 2 ways to solve my problem. The Qt way is to use QLocale::system().uiLanguages().
On my system it returns a list with a single item "en-US". The problem with that is I need a language name, like "english", so I'd have to add a map for converting language code to language name. It's no big deal, but I've decided to use WinAPI:
QString sysLangName;
const LANGID langId = GetUserDefaultUILanguage();
WCHAR langName[1000] = {0};
if (GetLocaleInfoW(MAKELCID(langId, SORT_DEFAULT), LOCALE_SENGLANGUAGE, langName, sizeof langName / sizeof langName[0] - 1) != 0)
sysLangName = QString::fromWcharArray(langName);

Answer 3

I had the same problem and I solved with this code.
QString local = QLocale::languageToString(QLocale::system().language());

Answer 4

To get the language name you can simply use QLocale::languageToString(QLocale::system().language()); or maybe QLocale::system().nativeLanguageName(); but the real problem is as you mentioned that the QLocale::system() does not always match the actual system locale on windows. This can be observed if you change the locale during program execution. In this case the QLocale::system() does not get up-to-date and returns the old value. Here is a workaround I used in Qt5:
class WinEventFilter : public QAbstractNativeEventFilter
{
public:
bool nativeEventFilter(const QByteArray &eventType, void *message, long *result)
{
if (((MSG*)message)->message == WM_WININICHANGE )
{
// Workaround - in Qt5 the system locale is not up to date and we have to manually update it.
#ifdef _DEBUG
QLibrary lib("Qt5Cored.dll");
#else
QLibrary lib("Qt5Core.dll");
#endif
void (* func)() = lib.resolve("?updateSystemPrivate#QLocalePrivate##SAXXZ");
if (func)
func();
else
qDebug()<<"! Unable to resolve updateSystemPrivate()";
// Workaround end
qDebug()<<"WM_WININICHANGE"<<QLocale::languageToString(QLocale::system().language());
}
return false;
}
};
and my application class constructor looks like this:
MyApplication::MyApplication( int & argc, char ** argv )
: QApplication(argc, argv)
{
WinEventFilter *pFilter = new WinEventFilter(this);
installNativeEventFilter(m_pEventFilter);
}
Hope this helps.