Ruby on rails 3.1 如何在视图中调用嵌套的_li

我正在创建一个rails应用程序，其中我必须创建一个教程网站，因为我想在我的索引页面上显示课程列表，当用户选择一门课程时，它将重定向到其显示页面，其中包含该课程的不同部分和子部分，在一个部分下可以没有任何子部分<代码>**例如**

课程是rubyonrails，

下面我们有这样一节

1.Introduction
 1.1 What is ruby
 1.2 Small program in ruby
  1.2.1 Say hello world
   1.2.1.1 Welcome user
   1.2.1.2 array in ruby
  1.2.2 User Interface
 1.3 Introduction to irb
2. Introduction to rails.

我希望在我的应用程序中使用这种嵌套li

我已经在助手窗体中为嵌套li编写了代码。我的

courses\u helper.rb

文件中的代码是

def nested_li(objects)
  output = ""

  output += "<ul>"
  path = [nil]
  objects.each do |o|
    if o.parent_id != path.last
      # we are on a new level, did we decent or ascent?
      if path.include?(o.parent_id)
        # remove wrong wrong tailing paths elements
        while path.last != o.parent_id
          path.pop
          output += "\n</ul>"
        end
      else
        path << o.parent_id
        output += "\n<ul>"
      end
    end
    output += "\n<li>#{yield o}</li>"
  end
  #pop off unfinished paths elements
  while path.length > 1
    path.pop
    output += "\n</ul>"
  end
  output += "\n</ul>"
  return output.html_safe
end

谁能帮我解决这个问题。正如我在上面的示例中所示，此代码无法正确调用嵌套的子节。我用了一颗树宝石。请帮帮我。谢谢

def显示部分（部分，课程id）
def display_sections(sections, course_id)
section_array = []
       <ul class='nav nav-list '>"
  for section in sections
   if(!section_array.include?(section.id))
       if section.children.present?
          ret += "<li class='item'>"
        ret += "<div id='sectiontitle_#{section.id}' class='section_title'>" 
        ret +="<span id='section_#{section.id}'>"            
        ret += "</span>"
        ret += "<br/>"
        ret += "</div>"
          ret += find_all_subsections(section, section_array, course_id)

          ret += "</li>"

          section_array << section.id
      else
         ret += "<li class='item'>"
         ret += "<div id='sectiontitle_#{section.id}' class='section_title'>"
           ret += link_to section.title,course_section_path(course_id, section.id), :title=> "#{section.id}"
         ret +="<span id='section_#{section.id}'>"
         ret += "</span>"
         ret += "</div>"
           ret += "</li>"


           section_array << section.id
       end
   end
  end
  ret += "</ul>"
  ret.html_safe
  end

 def find_all_subsections(section, section_array, course_id)

  if section.children.size > 0
    ret = '<ul class="nav nav-list">'
    section.children.each { |subsection|
      section_array << subsection.id
      if subsection.children.present?
        ret += "<li>"
        ret += "<div id='sectiontitle_#{subsection.id}' class='section_title'>"
        ret += link_to h(subsection.title),course_section_path(course_id, subsection.id), :class => 'sub_item', :title=> "#{subsection.id}"
        ret += "<br/>"
        ret +="<span id='section_#{subsection.id}'>"            
        ret += "</span>"
        ret += "</div>"
        ret += find_all_subsections(subsection, section_array, course_id)
        ret += '</li>'

      else
        ret += "<li class='item'>"
        ret += "<div id='sectiontitle_#{subsection.id}' class='section_title'>"
        ret += link_to h(subsection.title),course_section_path(course_id, subsection.id), :class => 'sub_item', :title=> "#{subsection.id}"
        ret +="<span id='section_#{subsection.id}' style='display:none;' class='pull-right'>"
        ret += "<br/>"

        ret += "</div>"
        ret += '</li>'
        section_array << subsection.id
      end
      }
    ret += '</ul>'
  end
end

节_数组=[]
“
一节接一节
if（！section_array.include？（section.id））
如果你的孩子在场？
ret+=“
”
ret+=“”
ret+=“”
ret+=“”
ret+=“
”
ret+=“”
ret+=查找所有子部分（节、节数组、课程id）
ret+=“
”
节数组“#{section.id}”
ret+=“”
ret+=“”
ret+=“”
ret+=“”
节数组0
ret='
'
第3.1节儿童每{|小节|
节数组'sub_item'，：title=>“#{subsection.id}”
ret+=“
”
ret+=“”
ret+=“”
ret+=“”
ret+=查找所有子部分（子部分、节数组、课程id）
ret+=''
其他的
ret+=“
”
ret+=“”
ret+=链接到h（subsection.title），课程部分路径（课程id，subsection.id），：class=>“subsection\u item”，：title=>“#{subsection.id}”
ret+=“”
ret+=“
”
ret+=“”
ret+='
'
由于我的问题没有找到答案，我试图自己解决它，我发现下面的解决方案对我来说绝对有效。任何人都可以尝试。
def display_sections(sections, course_id)
section_array = []
       <ul class='nav nav-list '>"
  for section in sections
   if(!section_array.include?(section.id))
       if section.children.present?
          ret += "<li class='item'>"
        ret += "<div id='sectiontitle_#{section.id}' class='section_title'>" 
        ret +="<span id='section_#{section.id}'>"            
        ret += "</span>"
        ret += "<br/>"
        ret += "</div>"
          ret += find_all_subsections(section, section_array, course_id)

          ret += "</li>"

          section_array << section.id
      else
         ret += "<li class='item'>"
         ret += "<div id='sectiontitle_#{section.id}' class='section_title'>"
           ret += link_to section.title,course_section_path(course_id, section.id), :title=> "#{section.id}"
         ret +="<span id='section_#{section.id}'>"
         ret += "</span>"
         ret += "</div>"
           ret += "</li>"


           section_array << section.id
       end
   end
  end
  ret += "</ul>"
  ret.html_safe
  end

 def find_all_subsections(section, section_array, course_id)

  if section.children.size > 0
    ret = '<ul class="nav nav-list">'
    section.children.each { |subsection|
      section_array << subsection.id
      if subsection.children.present?
        ret += "<li>"
        ret += "<div id='sectiontitle_#{subsection.id}' class='section_title'>"
        ret += link_to h(subsection.title),course_section_path(course_id, subsection.id), :class => 'sub_item', :title=> "#{subsection.id}"
        ret += "<br/>"
        ret +="<span id='section_#{subsection.id}'>"            
        ret += "</span>"
        ret += "</div>"
        ret += find_all_subsections(subsection, section_array, course_id)
        ret += '</li>'

      else
        ret += "<li class='item'>"
        ret += "<div id='sectiontitle_#{subsection.id}' class='section_title'>"
        ret += link_to h(subsection.title),course_section_path(course_id, subsection.id), :class => 'sub_item', :title=> "#{subsection.id}"
        ret +="<span id='section_#{subsection.id}' style='display:none;' class='pull-right'>"
        ret += "<br/>"

        ret += "</div>"
        ret += '</li>'
        section_array << subsection.id
      end
      }
    ret += '</ul>'
  end
end