ruby-on-rails - 分组形式选择

现在使用Formtastic，我可以选择:

= f.input :category, :as => :select, :include_blank => false, :collection => subcategories

在这里，我仅显示子类别。我将 actions_as_tree 插件用于父子关系。我也想显示父类别。

Formtastic生成的select应该如下所示:

<select name="favoritefood">
  <optgroup label="Dairy products">
    <option>Cheese</option>
    <option>Egg</option>
  </optgroup>
  <optgroup label="Vegetables">
    <option>Cabbage</option>
    <option>Lettuce</option>
    <option>Beans</option>
    <option>Onions</option>
  <option>Courgettes</option>
  </optgroup>
  ⋮
</select>

如何在带有act_as_tree功能的模型的Formtastic select中使用分组？有人知道吗

更新了

我发现这应该可行:

= f.input :category, :include_blank => false, :group_by => :parent

但这并没有错误:

undefined local variable or method `object_class' for #<Formtastic::SemanticFormBuilder:0x87d3158>

看来Formtastic中有一些错误。我浏览了formtastic.rb，并在 detect_group_association 方法中找到了object_class:

  def detect_group_association(method, group_by)
    object_to_method_reflection = self.reflection_for(method)
    method_class = object_to_method_reflection.klass

    method_to_group_association = method_class.reflect_on_association(group_by)
    group_class = method_to_group_association.klass

    # This will return in the normal case
    return method.to_s.pluralize.to_sym if group_class.reflect_on_association(method.to_s.pluralize)

    # This is for belongs_to associations named differently than their class
    # form.input :parent, :group_by => :customer
    # eg.
    # class Project
    #   belongs_to :parent, :class_name => 'Project', :foreign_key => 'parent_id'
    #   belongs_to :customer
    # end
    # class Customer
    #   has_many :projects
    # end
    group_method = method_class.to_s.underscore.pluralize.to_sym
    return group_method if group_class.reflect_on_association(group_method) # :projects

    # This is for has_many associations named differently than their class
    # eg.
    # class Project
    #   belongs_to :parent, :class_name => 'Project', :foreign_key => 'parent_id'
    #   belongs_to :customer
    # end
    # class Customer
    #   has_many :tasks, :class_name => 'Project', :foreign_key => 'customer_id'
    # end
    possible_associations =  group_class.reflect_on_all_associations(:has_many).find_all{|assoc| assoc.klass == object_class}
    return possible_associations.first.name.to_sym if possible_associations.count == 1

    raise "Cannot infer group association for #{method} grouped by #{group_by}, there were #{possible_associations.empty? ? 'no' : possible_associations.size} possible associations. Please specify using :group_association"

  end

的确，此方法未定义 object_class ，formtastic.rb中没有使用该名称的privat方法。但是我们可以使用:group_association 显式定义关联。

- semantic_form_for ([:manager, @purchase_profile]) do |f|
  - f.inputs do
    = f.input :category, :include_blank => false, :group_by => :parent, :group_association => :children
  = f.buttons

但我遇到了另一个错误:

undefined method `children' for nil:NilClass

我尝试了关闭 Acts_as_tree 并编写了自己的自引用关联。与Acts_as_tree相同的作品应如下所示:

class Category < ActiveRecord::Base
  belongs_to :parent, :class_name => "Category", :foreign_key => "parent_id"
  has_many :children, :class_name => "Category", :foreign_key => "parent_id"
end

错误是一样的。有人可以帮忙吗？

更新了

下一步。这段没有Formtastic的代码可以正常工作:

= grouped_collection_select('', :category_id, top_categories, :children, :name, :id, :name, :include_blank => true)

附注:top_categories是带有父类别集合的帮助方法。

最后一件事是将其转换为Formtastic语法:)

最佳答案

如果有人遇到相同的问题，则可以执行以下操作:

<%= f.input :category, :as => :select, :collection => option_groups_from_collection_for_select(ParentCategory.all, :categories, :name, :id, :name) %>

Reference from Rails API
Recommendation from Justin French(他提到删除:group_by)