现在有了 Formtastic，我有了简单的选择：
= f.input :category, :as => :select, :include_blank => false, :collection => subcategories
在这里，我只显示儿童类别。我使用acts_as_tree插件来处理父子关系。我也想显示父类别。
Formtastic 生成的选择应该如下所示：
<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 Formtastic 中为具有acts_as_tree 功能的模型选择分组？有人知道吗？
更新
我发现这应该可行：
= f.input :category, :include_blank => false, :group_by => :parent
但它没有错误：
undefined local variable or method `object_class' for #<Formtastic::SemanticFormBuilder:0x87d3158>
看起来 Formtastic 中存在一些错误。我查看了 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
实际上object_class在此方法中未定义，并且在 formtastic.rb 中没有具有该名称的 privat 方法。但是我们可以使用:group_association明确定义关联。
- 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
我尝试关闭Acts_as_tree并编写我自己的自引用关联。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
下一个小步骤。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)
ps：top_categories 是带有父类别集合的辅助方法。
最后一件事是将它翻译成 Formtastic 语法:)