上移下移功能

app/controllers/courses_controller.rb

@@ -291,8 +291,8 @@ class CoursesController < ApplicationController
       if next_inform.blank?
         render_error('已经到达最顶部')
       else
-        inform.update_attribute(:position, (position + 1))
-        next_inform.update_attribute(:position, last_inform.position - 1)
+        inform.update_attribute(:position, (inform.position + 1))
+        next_inform.update_attribute(:position, inform.position - 1)
         render_ok
       end
     end
@@ -305,8 +305,8 @@ class CoursesController < ApplicationController
       if last_inform.blank?
         render_error('已经到达最底部')
       else
-        inform.update_attribute(:position, (position - 1))
-        last_inform.update_attribute(:position, last_inform.position + 1)
+        inform.update_attribute(:position, (inform.position - 1))
+        last_inform.update_attribute(:position, inform.position + 1)
         render_ok
       end
     end