百分比除数为0问题

app/controllers/poll_controller.rb

@@ -178,20 +178,26 @@ class PollController < ApplicationController
       #单选题
       pv = PollVote.find_by_poll_question_id_and_user_id(params[:poll_question_id],User.current.id)
       if pv.nil?
+        #尚未答该题，添加答案
         pv = PollVote.new
         pv.user_id = User.current.id
         pv.poll_question_id = params[:poll_question_id]
       end
+      #修改该题对应答案
       pv.poll_answer_id = params[:poll_answer_id]
       if pv.save
+        #保存成功返回成功信息及当前以答题百分比
         @percent = get_percent(@poll,User.current)
         render :json => {:text => "ok" ,:percent => format("%.2f" ,@percent)}
       else
+        #返回失败信息
         render :json => {:text => "failure"}
       end
     elsif pq.question_type == 2
+      #多选题
       pv = PollVote.find_by_poll_answer_id_and_user_id(params[:poll_answer_id],User.current.id)
       if pv.nil?
+        #尚未答该题，添加答案
         pv = PollVote.new
         pv.user_id = User.current.id
         pv.poll_question_id = params[:poll_question_id]
@@ -203,6 +209,7 @@ class PollController < ApplicationController
           render :json => {:text => "failure"}
         end
       else
+        #pv不为空，则当前选项之前已被选择，再次点击则是不再选择该项，故删除该答案
         if pv.delete
           @percent = get_percent(@poll,User.current)
           render :json => {:text => "false" ,:percent => format("%.2f" ,@percent)}
@@ -211,12 +218,16 @@ class PollController < ApplicationController
         end
       end
     elsif pq.question_type == 3 || pq.question_type == 4
+      #单行文本，多行文本题
       pv = PollVote.find_by_poll_question_id_and_user_id(params[:poll_question_id],User.current.id)
       if pv.nil?
+        #pv为空之前尚未答题，添加答案
         if params[:vote_text].nil? || params[:vote_text].blank?
+          #用户提交空答案，视作不作答
           @percent = get_percent(@poll,User.current)
           render :json => {:text => pv.vote_text,:percent => format("%.2f" ,@percent)}
         else
+          #添加答案
           pv = PollVote.new
           pv.user_id = User.current.id
           pv.poll_question_id = params[:poll_question_id]
@@ -229,7 +240,9 @@ class PollController < ApplicationController
           end
         end
       else
+        #pv不为空说明用户之前已作答
         if params[:vote_text].nil? || params[:vote_text].blank?
+          #用户提交空答案，视为删除答案
           if pv.delete
             @percent = get_percent(@poll,User.current)
             render :json => {:text => pv.vote_text,:percent => format("%.2f" ,@percent)}
@@ -237,6 +250,7 @@ class PollController < ApplicationController
             render :json => {:text => "failure"}
           end
         else
+          #用户修改答案
           pv.vote_text = params[:vote_text]
           if pv.save
             @percent = get_percent(@poll,User.current)
@@ -335,7 +349,11 @@ class PollController < ApplicationController
 
   def get_percent poll,user
     complete_count = get_complete_question(poll,user).count
-    (complete_count.to_f / poll.poll_questions.count.to_f)*100
+    if poll.poll_questions.count == 0
+      return 0
+    else
+      return (complete_count.to_f / poll.poll_questions.count.to_f)*100
+    end
   end
 
   #PollUser记录用户是否已提交问卷有对应的记录则已提交，没有则新建一个