Rails，是否可以根據包含餘額的表的列值更改顏色？

Question

index.html.erb

<% balance = 0 %> 

    <table align="center" width="50%" cellpadding="1" cellspacing="5"> 
     <tr> 
      <td>Amount</td> 
      <td>Discount</td> 
      <td>Paid</td> 
      <td>Balance</td> 
     </tr> 

<% @statements.each do |statement| %> 

    <tr class="tr-<%= cycle('odd', 'even') %>"> 

    <td class="col-1"><%= statement.date %></td> 
    <td class="col-3"><%= statement.description %></td> 

    <td class="col-1"><%= number_with_precision(statement.amount, :delimiter => ",", :precision => 2) %></td> 

    <td class="col-1 neg"><%= number_with_precision(statement.discount, :delimiter => ",", :precision => 2) %></td> 

    <td class="col-1 neg"><%= number_with_precision(statement.paid, :delimiter => ",", :precision => 2) %></td> 


<% balance += statement.amount.to_f - statement.discount.to_f - statement.paid.to_f %> 

     <% color = balance >= 0 ? "pos" : "neg" %> 

     <td class="col-1 <%= color %>"><%= number_with_precision(balance.abs, :delimiter => ",", :precision => 2) %></td> 

</tr> 

    <% end %> 

    </table> 

<center><p><b><%= number_to_currency(balance.abs, :unit => 'AED ', :delimiter => ",", :precision => 2) %></b></p></center> 

我想有一個是平衡實體的顏色變化時餘額是正就必須表現出黑色和變負時，它必須顯示爲紅色。

這裏是我的application.css.scss

.pos { color: #000; } 
.neg { color: #f00; } 

我沒有得到的結果如預期。

請看下面的結果;

Sample data

picture

Answer 1

裏克是正確的，但有一個小故障。

正如我在上面的評論中提到的那樣，在計算新值之前，正在使用餘額值來分配類.neg or .pos。這是負責它採取以前的balance價值給它的類如附件中所示的樣本。

下面是你如何使用它來得到它正常工作之前計算出新的價值：

<% balance = 0 %> 

<table align="center" width="50%" cellpadding="1" cellspacing="5"> 
    <tr> 
     <td>Amount</td> 
     <td>Discount</td> 
     <td>Paid</td> 
     <td>Balance</td> 
    </tr> 

    <% @statements.each do |statement| %> 

    <tr> 

     <td><%= statement.amount %></td> 

     <td class="neg"><%= statement.discount %></td> 
     <td class="neg"><%= statement.paid %></td> 

     <% balance += statement.amount.to_f - statement.discount.to_f - statement.paid.to_f %> 

     <% color = balance >= 0 ? "pos" : "neg" %> 

     <td class="<%= color %>"><%= balance %></td> 

    </tr> 

    <% end %> 

</table> 

發現，我們首先在任何操作在使用它之前計算的balance新值。這樣，在分配課程時，balance保留了當前循環的真實和正確的值。

試試這個，讓我們知道你在視圖上得到了什麼......

Answer 2

當然，just use CSS：

#app/assets/stylesheets/application.css 
tr.pos { color: #000; } 
tr.neg { color: #f00; } 

#app/views/controller/index.html.erb 
<% color = balance >= 0 ? "pos" : "neg" %> 

<td class="col-1 <%= color %>"><%= number_with_precision(statement.discount, :delimiter => ",", :precision => 2) %></td> 
<td class="col-1 <%= color %>"><%= number_with_precision(statement.paid, :delimiter => ",", :precision => 2) %></td> 
<td class="col-1 <%= color %>"><%= number_with_precision(balance += statement.amount.to_f - statement.discount.to_f - statement.paid.to_f, :delimiter => ",", :precision => 2) %></td>