Define and use TranslatableStringArray. This lets you define "listeners"...

... for language changes, without inserting extra code to send the
notifications.

src/TranslatableStringArray.h

@@ -0,0 +1,80 @@
+/**********************************************************************
+
+Audacity: A Digital Audio Editor
+
+TranslatableStringArray.h
+
+Paul Licameli
+
+**********************************************************************/
+
+#ifndef __AUDACITY_TRANSLATABLE_STRING_ARRAY__
+#define __AUDACITY_TRANSLATABLE_STRING_ARRAY__
+
+#include <vector>
+#include <wx/app.h>
+#include <wx/event.h>
+
+class wxArrayString;
+
+DECLARE_EXPORTED_EVENT_TYPE(AUDACITY_DLL_API, EVT_LANGUAGE_CHANGE, -1);
+
+/*
+This class can maintain a static table containing user visible strings that updates
+itself properly when the language is changed in Preferences.
+
+Typical usage is to define a derived class, override Populate(), and then
+make a singleton instance of the class.
+
+Populate() is called only as needed to fill the table on demand the first
+time it is used after application startup or language change.
+*/
+
+template<typename ArrayType> class TranslatableArray
+   : public wxEvtHandler
+{
+public:
+
+   TranslatableArray()
+   {
+      if (wxTheApp)
+         wxTheApp->Connect(EVT_LANGUAGE_CHANGE,
+            wxCommandEventHandler(TranslatableArray::Invalidate),
+            NULL,
+            this);
+   }
+
+   ~TranslatableArray()
+   {
+      if (wxTheApp)
+         wxTheApp->Disconnect(EVT_LANGUAGE_CHANGE,
+            wxCommandEventHandler(TranslatableArray::Invalidate),
+            NULL,
+            this);
+   }
+
+   const ArrayType& Get()
+   {
+      if (mContents.empty())
+         Populate();
+      return mContents;
+   }
+
+protected:
+   // Override this function to fill in mContents,
+   // typically by lines like
+   // mContents.push_back(_("Translate me"));
+   virtual void Populate() = 0;
+
+   void Invalidate(wxCommandEvent &evt)
+   {
+      mContents.clear();
+      evt.Skip();
+   }
+
+   ArrayType mContents;
+};
+
+typedef TranslatableArray<wxArrayString> TranslatableStringArray;
+
+#endif