Add localization for UI

Author: osamacis

src/bitmessagekivy/base_navigation.py

@@ -2,7 +2,8 @@
 """
     Base class for Navigation Drawer
 """
-
+import gettext
+import os
 from kivy.lang import Observable
 
 from kivy.properties import (
@@ -35,9 +36,36 @@ def __init__(self, defaultlang):
         self.ugettext = None
         self.lang = defaultlang
 
-    @staticmethod
-    def _(text):
-        return text
+    def _(self, text):
+        # return  text
+        return self.ugettext(text)
+
+    def fbind(self, name, func, args, **kwargs):
+        """Function for binding to observers """
+        if name == "_":
+            self.observers.append((func, args, kwargs))
+        else:
+            return super(BaseLanguage, self).fbind(name, func, *args, **kwargs)
+
+    def funbind(self, name, func, args, **kwargs):
+        """Function for unbinding to observers """
+        if name == "_":
+            key = (func, args, kwargs)
+            if key in self.observers:
+                self.observers.remove(key)
+        else:
+            return super(BaseLanguage, self).funbind(name, func, *args, **kwargs)
+
+    def switch_lang(self, lang):
+        """Function language switching """
+        # get the right locales directory, and instanciate a gettext
+        locale_dir = os.path.join(os.path.dirname(__file__), 'translations', 'locales')
+        locales = gettext.translation('langapp', locale_dir, languages=[lang])
+        self.ugettext = locales.gettext
+
+        # update all the kv rules attached to this text
+        for func, largs, in self.observers:
+            func(largs, None, None)
 
 
 class BaseNavigationItem(OneLineAvatarIconListItem):