[wxPython-users] Re: wx.Locale mystery

[Robin Dunn]

Donn Ingle wrote:
> Well, 
>  In follow up: I have had some success. With that great tip from Stefano
> things are looking up. Here's the nutshell:

I'd like to add a bit more info here for the record.

1. The reason that you need to keep a reference to the wx.Locale object 
is because the former locale is restored when the C++ wx.Locale instance 
is destroyed.  So if you are setting to a locale other than what is the 
system's default you must keep that reference until the end of the 
program or until you want to switch or restore locales.

2. If you have already created one wx.Locale, and want to create another 
one to switch to a different language, then because of the order that 
Python manages garbage collection you have to be careful how you do it. 
  The problem arises when you have code like this:

	self.loc = wx.Locale(FOO1)
	...
	self.loc = wx.Locale(FOO2)

In this case the first locale object is not destroyed until after the 
2nd one is created, but since the C++ object will restore the "former" 
locale when the object is destroyed then you end up with no current 
locale set, and a bad pointer that will likely cause a crash when the 
FOO2 object is eventually destroyed.  So instead you  need to do 
something like this to give the first object a chance to be destroyed 
before the 2nd one is created (and make sure you only have the single 
reference to the locale object):

	self.loc = wx.Locale(FOO1)
	...
	del self.loc
	self.loc = wx.Locale(FOO2)

3. On Linux/Unix there are a few non-obvious things that need to be done 
to make it work.  First the system locales need to be set up for the 
languages that you want to support, otherwise the C runtime library will 
refuse to switch to the locale and the init of wx.Locale will fail.  You 
can run "locale -a" to see what locales the system can support.  Second 
the message catalogs for GTK need to be installed for the "native" 
buttons, dialogs, etc. to get the translated text.  (It seems like there 
was a 3rd item that I can't remember right now...)


-- 
Robin Dunn
Software Craftsman
http://wxPython.org  Java give you jitters?  Relax with wxPython!