问题
Now with Formtastic I have plain select:
= f.input :category, :as => :select, :include_blank => false, :collection => subcategories
Here I show only children categories. I use acts_as_tree plugin for parent-child relationship. I would like to show parent categories as well.
Formtastic generated select should look like this one:
<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>
How to use grouping in Formtastic select for model with acts_as_tree functionality? Does anybody know?
UPDATED
I figured out that this should work:
= f.input :category, :include_blank => false, :group_by => :parent
but it doesn't with error:
undefined local variable or method `object_class' for #<Formtastic::SemanticFormBuilder:0x87d3158>
It looks like there is some bug in Formtastic. I have looked through formtastic.rb and found object_class in detect_group_association method:
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
Indeed object_class undefined in this method and there is no privat method with that name in formtastic.rb. But we can use :group_association to define association explicitly.
- 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
but I ran into another error:
undefined method `children' for nil:NilClass
I tried swith off Acts_as_tree and write my own self-referenced assositions. The same as Acts_as_tree works should look like:
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
Error is the same. Can anybody help?
Updated
Next little step. This code without Formtastic works fine:
= grouped_collection_select('', :category_id, top_categories, :children, :name, :id, :name, :include_blank => true)
p.s: top_categories is helper method with collection of parent categories.
The last thing is translate it into Formtastic syntax :)
回答1:
In case anyone is having the same problem, you can do the following:
<%= 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 (he mentions removing the :group_by)
回答2:
Hey, so I was trying to solve a particular problem with formtastic, and discovered that you can modify the query used to build the list by using :find_options. Looking at the code, I saw that if you don't specify :group_by, then the list of values ultimately comes down to a find(:all) on the model object (in a method called find_raw_collection_for_column in formtastic.rb). The parameters after the :all are the set of parameters specified by :find_options. Thus, you can apply any conditions or other parameters that you would normally use in find(*args) (see http://ar.rubyonrails.org/classes/ActiveRecord/Base.html#M000333). Personally, I added this to my f.input statement:
:find_options => {:conditions => {:country_id => @business.country ? @business.country.id : nil}}
By doing this, I limited the select statement for the query to only the current county ID. But you should be able to use :group in a similar manner to specify who you wanted to GROUP BY in your query, like this:
:find_options => {:group => 'parent.id'}
Hopes this helps.
回答3:
Why not try building your list of items in a helper and then passing that into the select tag?
I don't know much about formtastic, or acts_as_tree, but if you are having problems getting it working how you have above, I think resorting to building your options before passing them to your select is perfectly reasonable.
来源:https://stackoverflow.com/questions/2154169/formtastic-select-with-grouping