Translation does not work when the text of QLineEdit is modified

Zoltan

I have a desktop application I want to translate. All translations work well except in the following case. I have a QLineEdit object called resultEdit whose text is updated when a pushbutton is clicked on. resultEdit can display the following strings:

const QString days[7] = {QCoreApplication::tr("Monday"), \
                         QCoreApplication::tr("Tuesday"), \
                         QCoreApplication::tr("Wednesday"), \
                         QCoreApplication::tr("Thursday"), \
                         QCoreApplication::tr("Friday"), \
                         QCoreApplication::tr("Saturday"), \
                         QCoreApplication::tr("Sunday")};

So days is a global array. One callback functions which calculates which day to print is

void ZellerGUI::on_yearEdit_editingFinished()
{
    // Calculate the day of the week
    int calculatedDay = some_integer_from_1_to_7;
    ui->resultEdit->setText(days[calculatedDay - 1]);
}

However, when I select the translation, the names of the days remain in English. It is weird as all other stings are translated well. When I opened the Linguist, it recognised all seven days. What happens in the background that the translations do not work for this global array?

Zoltan

@kshegunov I just used your previous solution:

QString day = QCoreApplication::tr(days[calculatedDay - 1]);

Using your last command

QString day = QCoreApplication::translate("Weekdays", days[calculatedDay - 1]);

perfectly works. Now I just have to think it over why it works.

Thank you very much for your precious help!

sierdzio

Could it be that static string is built into the binary so it is not being initialized after you load translation QM file?

Zoltan

@sierdzio I don't know the inner working of Qt. If it is so, then what would you recommend me to modify?

sierdzio

This is rather inner working of C++ itself. But I am only guessing to be honest.

What you can try is to define this string array (btw. you can also use QStringList) in a singleton class that is initialized after translation is loaded, so that it gets correct data.

Zoltan

@sierdzio My constant variable is called from the ui. But the ui class is instantiated after the translation is loaded. Shouldn't it be OK (it isn't)?

kshegunov

Try something like this:

const char * const days[7] = {
    QT_TR_NOOP("Monday"),
    QT_TR_NOOP("Tuesday"),
    // ... and so on
}

void ZellerGUI::on_yearEdit_editingFinished()
{
    // ... calculate day
    QString day = QCoreApplication::tr(days[calculatedDay - 1]);
    ui->resultEdit->setText(day);
}

Zoltan

@kshegunov When I call lupdate on the project file, it throws these warnings:

tr() cannot be called without context

and these strings do not appear in Linguist.

kshegunov

Yes I think my example is rotten. Try with QT_TRANSLATE_NOOP and give it a context:

const char * const days[7] = {
    QT_TRANSLATE_NOOP("Weekdays", "Monday"),
    QT_TRANSLATE_NOOP("Weekdays", "Tuesday"),
    // ... and so on
}

Zoltan

@kshegunov Thank you. Now Linguist recognizes it but my application doesn't appreciate it yet. In the debugger, I also see the English name.

kshegunov

Well, did you translate it?

QString day = QCoreApplication::translate("Weekdays", days[calculatedDay - 1]);

Zoltan

@kshegunov I just used your previous solution:

QString day = QCoreApplication::tr(days[calculatedDay - 1]);

Using your last command

QString day = QCoreApplication::translate("Weekdays", days[calculatedDay - 1]);

perfectly works. Now I just have to think it over why it works.

Thank you very much for your precious help!

kshegunov

You're welcome.
Happy coding!

Edit:
Btw, moving the keys to the function should also work:

void ZellerGUI::on_yearEdit_editingFinished()
{
    // If this is initialized here it should work okay
    static const char * const days[7] = {
        QT_TR_NOOP("Monday"),
        QT_TR_NOOP("Tuesday"),
        // ... and so on
    };
    // ... calculate day
    QString day = QCoreApplication::tr(days[calculatedDay - 1]);
    ui->resultEdit->setText(day);
}

@Zoltan I have the same problem, must I do?

Update: Forum Guidelines & Code of Conduct

Qt World Summit: Early-Bird Tickets

Solved Translation does not work when the text of QLineEdit is modified