Qt Linguist translation error

[ivanicy]

Hello!

I am using Qt Linguist to translate my app to chinese. I want to do it inside the application, in a settings window.

I have a QComboBox to switch between the languages, and when I select the option, this is my code:

if (arg1.compare("Chinese", Qt::CaseInsensitive) == 0) {
        T.load(":/Translations/resources/translations/myApp_ch.qm");
        QApplication::installTranslator(&T);
        QCoreApplication::installTranslator(&T);
        ui->retranslateUi(this);
}

The problem is that there are some windows that do not translate.

However, if I do it from main.cpp, it works fine:

QApplication a(argc, argv);
QTranslator T;
T.load(":/Translations/resources/translations/myApp_ch.qm");
a.installTranslator(&T);

What am I doing wrong?

Thank you very guys!

[Christian Ehrlicher]

@ivanicy said in Qt Linguist translation error:

What am I doing wrong?

Only newly created windows are using the translator automatically. For the rest you have to watch for the LanguageChange event as explained here.

[ivanicy]

@Christian-Ehrlicher And, how should I do that? I have to reimplement the changeEvent in every windows in my app?

[Christian Ehrlicher]

@ivanicy said in Qt Linguist translation error:

I have to reimplement the changeEvent in every windows in my app?

if you want online translation, yes. I would simply restart the app / tell the user to do so.

[J.Hilk]

@ivanicy if all your translatable texts are inside your ui form classes, than it's a simple matter of calling

ui->retranslateUi(this);

on each form, after the translator is installed.

However, if you yourself set a - for translation marked -string inside your application (tr("")), you will have to set that string again after the translator is loaded and installed

[artwaw]

@ivanicy It's not that complicated. Basically you need to write custom slot for every class that has a form. Slot is rather simple:

void MainWindow::changeEvent(QEvent *e)
{
    QMainWindow::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        ui->retranslateUi(this);
        break;
    default:
        break;
    }
}

This is the example for a main program window (hence MainWindow and QMainWindow), but for classes that origin in, let's say, QDialog you'd obviously need to change code a bit.

[ivanicy]

@artwaw Yes, I know how to do it, but I have a lot of windows in my app hehe. Thank you very much guys. @J-Hilk @Christian-Ehrlicher.

I have another question about it. I have lines like this in my code:

QString sText;
if (sText.compare(tr("something"), Qt::CaseInsensitive) == 0) { ... }

In these cases, the compare function doesn't work. But I need to compare with the translated word. How can I fix it?

[Christian Ehrlicher]

@ivanicy said in Qt Linguist translation error:

In these cases, the compare function doesn't work.

What does this mean?

[ivanicy]

@Christian-Ehrlicher The compare function doesn't work when I have a tr() inside it. It doesn't enter in this if().

[Christian Ehrlicher]

Then you should look what tr("seomthing") returns matches what you're expecting.

[ivanicy]

@artwaw I have a stack overflow error in this function:

Do you know what is happening here?

Thank you very much!

[J.Hilk]

@ivanicy I would change your last line from
MainWindow::changeEvent(...)
to
QMainWindow::changeEvent(...)

therefore, making it nor a recursive function but rather a call to the base class.

[ivanicy]

@J-Hilk I use this function in more windows. I have to use QMainWindow in this windows too?

[artwaw]

@ivanicy Please look again at my example - let the QMainWindow try to handle the event first.
In your code you call QMainWindow at the last line of the method.

[artwaw]

@ivanicy said in Qt Linguist translation error:

I use this function in more windows. I have to use QMainWindow in this windows too?

First thing in the changeEvent is to call respective ancestor's changeEvent.

EDIT: I use QMainWindow in the example since I stated that it is for QMainWindow descendant. If your window inherits from QDialog you should call QDialog, etc...

[ivanicy]

This post is deleted!

[ivanicy]

@artwaw Thank you very much!

[ivanicy]

Sorry for bothering so much. I have detected that this method don't translate texts that I have put by coding, for example context menus or treeviews.

I use

ui->retranslateUi(this);

Is there something missing to translate the code part as well?

Thank you and sorry guys :(

[Christian Ehrlicher]

@ivanicy said in Qt Linguist translation error:

ui->retranslateUi(this);

As you can see, only the stuff in the ui struct can be translated with this call - how should this translate e.g. text from a model or somewhere else? The rest has to be done manually.

[J.Hilk]

@ivanicy said in Qt Linguist translation error:

Sorry for bothering so much. I have detected that this method don't translate texts that I have put by coding, for example context menus or treeviews.

I use

ui->retranslateUi(this);

Is there something missing to translate the code part as well?

Thank you and sorry guys :(

@J-Hilk said in Qt Linguist translation error:

However, if you yourself set a - for translation marked -string inside your application (tr("")), you will have to set that string again after the translator is loaded and installed