wxLocale and static wxString's translation

[ollydbg23]

Hi, What is the best place to set the language translation initialization?

For me, I have initialization the language here:

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bool MainApp::OnInit()
{
    int sysLang =  wxLocale::GetSystemLanguage();
    m_locale.Init(sysLang, wxLOCALE_LOAD_DEFAULT);
    wxLocale::AddCatalogLookupPathPrefix("yyyyy");
    if(!m_locale.AddCatalog("xxx.mo", xxxxx))
    {
        wxMessageBox("Can not load locals files");
    }
    ...

While, in some other cpp files, I have some static wxString members, such as:

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wxString SomeClass::m_Text = _("hello world");

But as the m_Text is a static member, it initialized before the MainApp::OnInit() function call.

So, my question is: What is the best place to initialize the language translation?

One possible way is to set this static member variable after MainApp::OnInit() function call, that it means I have to set this static member string twice. Any ideas? Thanks.

[PB]

I think the only other way besides initializing the string after the locale is set would be something like the code here
https://docs.wxwidgets.org/trunk/group_ ... 5ae9e14c45

[ollydbg23]

Thanks for the suggestion.

I think the only other way besides initializing the string after the locale is set would be something like the code here
https://docs.wxwidgets.org/trunk/group_ ... 5ae9e14c45

I'm a little puzzled, that:

I see the link suggest such usage:

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static const char * const elements[] = { wxTRANSLATE("Hydrogen"), wxTRANSLATE("Helium"), ... };
 ...
// use wxGetTranslation(elements[n])

But I see this still works:

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static const char * const elements[] = { _("Hydrogen"), _("Helium"), ... };
 ...
// use wxGetTranslation(elements[n])

[PB]

You mean it works when you only use _() when initializing elements and never calling wxGetTranslation()/_() on it?

I did not test it but TBH I find it suprising, unless elements is local and hence initialized after the locale is changed, i.e., when a function where it is defined is called for the first time...


EDIT
Does not work for me without wxGetTranslation(). Running this

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#include <wx/wx.h>

class MyDialog : public wxDialog
{
public:
    MyDialog(): wxDialog(nullptr, wxID_ANY, "Test")
    {
        wxBoxSizer* mainSizer = new wxBoxSizer(wxVERTICAL);

        wxButton* button = new wxButton(this, wxID_ANY, "Show strings");
        mainSizer->Add(button, wxSizerFlags().Expand().Border());
        button->Bind(wxEVT_COMMAND_BUTTON_CLICKED, &MyDialog::OnShowStrings, this);

        wxTextCtrl* logCtrl = new wxTextCtrl(this, wxID_ANY, wxEmptyString, wxDefaultPosition, wxDefaultSize, wxTE_MULTILINE | wxTE_READONLY | wxTE_RICH2);
        mainSizer->Add(logCtrl, wxSizerFlags().Proportion(1).Expand().Border());        
        wxLog::DisableTimestamp();
        wxLog::SetActiveTarget(new wxLogTextCtrl(logCtrl));    

        SetSizer(mainSizer);
    }	
private:
    static const char* ms_staticStr1;
    static const char* ms_staticStr2;
    
    void OnShowStrings(wxCommandEvent&)
    {    
        wxLogMessage("ms_staticStr1: %s", ms_staticStr1);        
        
        wxLogMessage("wxGetTranslation(ms_staticStr1): %s", wxGetTranslation(ms_staticStr1));
        wxLogMessage("wxGetTranslation(ms_staticStr2): %s", wxGetTranslation(ms_staticStr2));
    }
};

const char* MyDialog::ms_staticStr1 = _("ms_staticStr1 English");
const char* MyDialog::ms_staticStr2 = wxTRANSLATE("ms_staticStr2 English");

class MyApp : public wxApp
{
public:
    bool OnInit() override
    {
        wxLog::AddTraceMask(wxS("i18n"));

        if ( !m_locale.Init(wxLANGUAGE_CZECH) )
        {
            return false;
        }
        
        wxLocale::AddCatalogLookupPathPrefix(".");
        m_locale.AddCatalog("minimal");    
        m_locale.AddCatalog("wxstd");

        MyDialog().ShowModal();
        return false;
    }
private:
    wxLocale m_locale;
}; wxIMPLEMENT_APP(MyApp);

I get this

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ms_staticStr1: ms_staticStr1 English
wxGetTranslation(ms_staticStr1): ms_staticStr1 CZECH
wxGetTranslation(ms_staticStr2): ms_staticStr2 CZECH

[ollydbg23]

You mean it works when you only use _() when initializing elements and never calling wxGetTranslation()/_() on it?

I mean I use _() in the initialization of the static string instead of wxTRANSLATE(), and later I call wxGetTranslation() on the string.
I mean using _() is still OK, but we must call wxGetTranslation() later.

But the link https://docs.wxwidgets.org/trunk/group_ ... 5ae9e14c45
says we must use wxTRANSLATE() for the initialization of the static string, and later call wxGetTranslation() on the string.

And I see that in your below example, you have test both _() and wxTRANSLATE() cases, and the result is the same.

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const char* MyDialog::ms_staticStr1 = _("ms_staticStr1 English");
const char* MyDialog::ms_staticStr2 = wxTRANSLATE("ms_staticStr2 English");

result:

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wxGetTranslation(ms_staticStr1): ms_staticStr1 CZECH
wxGetTranslation(ms_staticStr2): ms_staticStr2 CZECH

Thanks for your time and effort to test it.

[doublemax]

The main issue is still that if you use _() for global variables, wxWidgets functions will be called before wxWidgets itself is initialized. Which may work or not and should be avoided.

In general, there shall be no global variable of a non-trivial wxWidgets class.

[ollydbg23]

The main issue is still that if you use _() for global variables, wxWidgets functions will be called before wxWidgets itself is initialized. Which may work or not and should be avoided.

I see, thanks.

In general, there shall be no global variable of a non-trivial wxWidgets class.

So, you suggest that using wxString as static member of a class is not a good idea?

Well, I do need to share some const strings(wxString) between classes, any good way to avoid this issue?

[ONEEYEMAN]

Hi,
What's wrong with passing it between functions as parameters?

And yes - static variable of all wx classes, but wxApp-descendant should be avoided.

Thank you.

[doublemax]

Well, I do need to share some const strings(wxString) between classes, any good way to avoid this issue?

Initialize them at run-time, e.g. with a static Init() function you call from wxApp::OnInit()

[ollydbg23]

Well, I do need to share some const strings(wxString) between classes, any good way to avoid this issue?

Initialize them at run-time, e.g. with a static Init() function you call from wxApp::OnInit()

OK, I understand, thanks.

The steps are:
1, leave the static member string as empty string in cpp, this way, the wxString default constructor will be call when initialized.

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wxString MyClass::s_String;

2, define a static member function like: MyClass::InitializedStaticString()

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MyClass::InitializedStaticString()
{
	s_String = _("XXX");
}

3, call this static function after I initialized the wxLocale staff in wxApp::OnInit().

[ONEEYEMAN]

Hi,
Why not just make it a member of wxApp-derived class and then make a getter/setter pair?

Thank you.

[ollydbg23]

Hi,
Why not just make it a member of wxApp-derived class and then make a getter/setter pair?

Thank you.

Hi, ONEEYEMAN, a bit late reply.
In-fact, I have a string array which is used to construct a wxChoice list in a setting dialog or a panel. I don't think this string array should belong to a wxApp-derived class.

[ONEEYEMAN]

Hi,
No it shouldn't.

Look at the widgets sample. It has a code showing how to implement it without using static variable.

Thank you.

[ollydbg23]

Hi,
No it shouldn't.

Look at the widgets sample. It has a code showing how to implement it without using static variable.

Thank you.

Which sample? Thanks.

[ONEEYEMAN]

Hi,
widgets sample.
Found in the wxWidgets\samples\widgets.

Thank you.