如何根据Rails中它的属性值更改记录的颜色？

Question

我有条目带属性的模型卡路里和日期。我也有用户模型属性expected_calories。当我显示条目列表时，如果每天的卡路里总和大于expected_calories，则应该显示为红色，否则应为绿色。

entries_controller.rb

def index 
@entries = Entry.where(user_id: current_user.id) 
@user = current_user 
if @user.role == 'admin' 
    @entries = Entry.all 
end 

末

index.html.slim

 h1 Listing entries 

    table.table 
     thead 
     tr 
      th Date 
      th Time 
      th Content 
      th Cal 
      th User 
      th 
      th 
      th 

     tbody 
     - if can? :manage, Entry 
      - @entries.each do |entry| 
      tr 
       td = entry.date 
       td = entry.time.strftime("%H:%M") 
       td = entry.content 
       td = entry.cal 
       td = entry.user.role 
       td = link_to 'Show', entry 
       td = link_to 'Edit', edit_entry_path(entry) 
       td = link_to 'Destroy', entry, data: { confirm: 'Are you sure?' }, method: :delete 

    br 

    = link_to 'New Entry', new_entry_path 

Answer 1

这是这样做的一个非常快速的肮脏的方式：

- if can? :manage, Entry 
    - @entries.each do |entry| 
    tr(style="background-color: #{entry.calories > current_user.expect_calories ? 'red' : 'green'}) 

我建议你创建一些css类。例如：

.expected-calories { 
    background: green 
} 
.unexpected-calories { 
    background: green 
} 

然后创建在helpers/entries_helper的方法：

def expected_calories_class(user, entry) 
    if user.expected_calories <= entry.calories 
    'expected-calories' 
    else 
    'unexpected-calories' 
    end 
end 

所以，你的看法会更可读（和逻辑是可测试）：

- if can? :manage, Entry 
    - @entries.each do |entry| 
    tr(class=expected_calories_class(current_user, entry))