strange behaviour of QLocale with QTranslator

django.Reinhard

Hi,

when I use QLocale with default constructor, then QTranslator fails to load translated texts. When I print the settings of QLocale - they are the same, as with second usage using explicit constructor.

This is the code:

//#define USE_SYSTEM_LOCALE


int main(int argc, char *argv[]) {
  QTranslator  translator;
  QApplication a(argc, argv);

#ifdef USE_SYSTEM_LOCALE
  QLocale      curLocale;

/*
 * qDebug output:
 *
 * current locale settings - lang:  QLocale::German 	country:  QLocale::Germany
 * locale messages found:  false
 */
#else
  QLocale      curLocale(QLocale::German, QLocale::Germany);

  /*
   * qDebug output:
   *
   * current locale settings - lang:  QLocale::German 	country:  QLocale::Germany
   * locale messages found:  true
   */
#endif
  bool         ok = translator.load(curLocale
                                  , "QtScreen"
                                  , "_"
                                  , "../QtScreen/src/i18n");

  qDebug() << "current locale settings - lang: " << curLocale.language()
           << "\tcountry: " << curLocale.country();
  qDebug() << "locale messages found: " << ok;
  a.installTranslator(&translator);
  MainWindow w;

  w.show();

  return a.exec();
  }

Any idea, how I could load localized strings without hardcoding my locale?

django.Reinhard

Hi,

ridiculous and strange, but I found a workaround:

  QLocale           sysLocale;
  QLocale::Language lang    = sysLocale.language();
  QLocale::Country  country = sysLocale.country();
  QLocale           curLocale(lang, country);

with that curLocale QTranslator finds the messages =:>

SGaist

Hi,

Pretty strange indeed...
Which version of Qt are you using ?
On which platform ?

django.Reinhard

I use qt5.15.2 at debian 11 (bullseye)

The solution sounds so unbelievable, that I did't check it earlier.
But hey - the workaround does what I want, so ... :)

SGaist

Would it be possible for you to provide a minimal compilable example that triggers this ?

django.Reinhard

Hi,

you could have a look at https://github.com/DjangoReinhard/QtUi
Its not minimal, but compilable.

You just need to look at main.cpp - current version is fixed to English.
So add a few comments and it should run/fail as described.

SGaist

Did you check what sysLocale.name() returns ?

I just tested with sysLocale on my system and it worked correctly (using a copy of your file renamed using my sysLocale name).

django.Reinhard

Result:

current locale settings - lang:  QLocale::German 	country:  QLocale::Germany 	name:  "de_DE"
syslocale.name:  "de_DE"
locale messages found:  false

from code:


int main(int argc, char *argv[]) {
  QTranslator       translator;
  QApplication      a(argc, argv);
  QLocale           sysLocale;
  QLocale::Language lang    = sysLocale.language();
  QLocale::Country  country = sysLocale.country();
  QLocale           curLocale; // (lang, country);
  bool              ok = translator.load(curLocale
                                       , "QtUi"
                                       , "_"
                                       , "../QtUi/src/i18n");

  qDebug() << "current locale settings - lang: " << curLocale.language()
           << "\tcountry: " << curLocale.country()
           << "\tname: " << curLocale.name();
  qDebug() << "syslocale.name: " << sysLocale.name();
  qDebug() << "locale messages found: " << ok;
  a.installTranslator(&translator);
  MainWindow w;

  w.show();

  return a.exec();
  }

... by the way: using Qt 6.2 works as expected :)

SGaist

5.15.2 from the online installer ?
Did you try with the one provided with your distribution ?

On my side it's 5.15.2 on macOS.

django.Reinhard

@SGaist said in strange behaviour of QLocale with QTranslator:

Did you try with the one provided with your distribution ?

Of cause, that was my first choice. Qt 5.15.2 on debian bullseye

Then with increasing issues I was curious about newer qt releases, so i started to use the online installer ...

SGaist

In that case, can you test the 5.15.2 from the installer ?

django.Reinhard

Hi,

I wasn't sure about my memory, so I repeated the tests:

5.15.2 provided by debian bullseye: fail
5.15.2 online installer: fail
6.2 online installer: works as expected

SGaist

Did you try to compare the system QLocale with the one you build by hand ?

django.Reinhard

If you look at my post before your last 3 questions you see the code, I'm using.