Rails的表視圖表示

Question

我試圖建立如下表視圖：

+----------+Actor 1+Actor 2+Actor 3+ 
+ REQ 1 + X +  + X + 
+ REQ 2 +  + X + X + 
+ REQ 3 + X + X + X + 
+ REQ 4 +  +  +  + 
+----------------------------------+ 

目前，我有以下代碼（不知道的方式，雖然建立它）：

<table class="table table-striped"> 
    <tr> 
    <th></th> 
    <% @project.actors.order('name').uniq.each do |actor| %> 
     <th><%= actor.name %></th> 
    <% end %> 
    </tr> 
    <% @project.requirements.order('position').each do |req, actors| %> 
    <tr> 
     <td><%= req.name_for_display %></td> 
     <% actors.sort_by{|a| a.name}.each do |actor| %> 
     <td><%= actor.name %></td> 
     <% end %> 
    </tr> 
    <% end %> 
</table> 

異常提出：undefined method `sort_by' for nil:NilClass

感謝您的幫助。

Answer 1

解決：這裏是工作的代碼

在控制器

def method_name 
    @project = Project.includes(:requirements => [:actors]).find(params[:id]) 
    @actors = @project.actors.index_by(&:id) 
end 

鑑於

<table class="table table-striped"> 
    <tr> 
    <th></th> 
    <% @actors.values.each do |actor| %> 
     <th><%= actor.name.titleize %></th> 
    <% end %> 
    </tr> 

    <% @project.requirements.order('position').each do |requirement, actors| %> 
    <% hash = requirement.actors.index_by(&:id) %> 
    <tr> 
     <td><%= link_to requirement.name_for_display, project_requirement_path(@project, requirement) %></td> 
     <% @actors.keys.each do |id| %> 
     <td><%= hash[id].present? ? "X" : nil %></td> 
     <% end %> 
    </tr> 
    <% end %> 
</table>