Add context to the evaluation of states and add readonly state for buttons

tryton/gui/window/view_form/view/form.py

@@ -178,7 +178,8 @@ class ViewForm(ParserView):
 
     def display(self):
         model = self.screen.current_model
-        values = {'state': 'draft'}
+        values = rpc.session.context.copy()
+        values['state'] = 'draft'
         if model:
             for field in model.mgroup.fields:
                 values[field] = model[field].get(model, check_load=False)

tryton/gui/window/view_form/view/form_gtk/parser.py

@@ -77,6 +77,13 @@ class Button(object):
                 self.widget.show()
         else:
             self.widget.show()
+        if 'readonly' in state_changes:
+            if eval(state_changes['readonly'], values):
+                self.widget.set_sensitive(False)
+            else:
+                self.widget.set_sensitive(True)
+        else:
+            self.widget.set_sensitive(True)
 
 class Label(gtk.Label):