How do I use select2-rails with simple_form?

Question

This select2 jquery library looks awesome. There is a Rails gem but it is very light on the documentation. I would like to generate a simple multiple drop-down menu, using autocomplete. How do I do that?

This is my simple_form_for call:

<%= f.input_field :neighborhood_names, url: autocomplete_neighborhood_name_searches_path, as: :autocomplete, data: { delimiter: ',', placeholder: "Where do you want to live?"}, multiple: true, id: "selectWhereToLive", class: "span8" %>

I have successfully installed the select2-rails gem, but not quite sure how to get it working.

I add this to my home.js.coffeefile:

jQuery ->
    $('#selectWhereToLive').select2()

And am getting this error:

Uncaught query function not defined for Select2 selectWhereToLive 

Thoughts?

Edit 1:

The above simple_form_for call is producing this HTML:

<input class="autocomplete optional span8" data-autocomplete="/searches/autocomplete_neighborhood_name" data-delimiter="," data-placeholder="Where do you want to live?" id="selectWhereToLive" multiple="multiple" name="search[neighborhood_names][]" size="30" type="text" url="/searches/autocomplete_neighborhood_name" value="" />

Indicating that the id attribute is being properly set.

Edit 2 - Updated

As @moonfly suggested, I tried adding as: :select to the f.input_field - both with as: :autocomplete included and not included.

The resulting HTML without as: :autocomplete was this:

<input name="search[neighborhood_names][]" type="hidden" value="" /><select class="select optional span8" data-delimiter="," data-placeholder="Where do you want to live?" id="selectWhereToLive" multiple="multiple" name="search[neighborhood_names][]" url="/searches/autocomplete_neighborhood_name"><option value="true">Yes</option>
<option value="false">No</option></select>

It pre-populates 2 option values 'Yes' and 'No'. Not quite sure why, but that is what it does.

Update

So I had changed the jquery selector to look for input#ID, and forgot. So I set that back and now it is generating the select box - but it is giving me those 2 Yes & No options. Not quite sure why it is doing that. It's not returning the values in from my url attribute.

Edit 3

@harish-shetty's suggestion seems to be working. But now, after it has successfully found the records via autocomplete and using the select2 menu, it is bypassing the setter method I have on my search.rb model.

Basically, what I want to happen is, once the user has finished filling out the form - and I have all the IDs/names for the neighborhoods they want, I want to create a new record in search_neighborhoods for those IDs.

So these are the methods I have:

Search.rb

  def neighborhood_names
    neighborhoods.map(&:name).join(',')
  end

  # we need to put [0] because it returns an array with a single element containing
  # the string of comma separated neighborhoods
  def neighborhood_names=(names)
    names[0].split(',').each do |name|
      next if name.blank?
      if neighborhood = Neighborhood.find_by_name(name)
        search_neighborhoods.build neighborhood_id: neighborhood.id
      end
    end
  end

My SearchController.rb

  def autocomplete_neighborhood_name
    @neighborhood = Neighborhood.select("id, name").where("name LIKE ?", "#{params[:name]}%").order(:name).limit(10)

    respond_to do |format|
      format.json { render json: @neighborhood , :only => [:id, :name] }
    end    
  end

This is what a request looks like right now - which shows that no search_neighborhood records are being created:

Started POST "/searches" for 127.0.0.1 at 2013-03-06 04:09:55 -0500
Processing by SearchesController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"7SeA=", "search"=>{"boro_id"=>"", "neighborhood_names"=>"1416,1394", "property_type_id"=>"", "min_price"=>"", "max_price"=>"", "num_bedrooms"=>"", "num_bathrooms"=>""}}
  Neighborhood Load (0.5ms)  SELECT "neighborhoods".* FROM "neighborhoods" WHERE "neighborhoods"."name" = '1' LIMIT 1
   (0.3ms)  BEGIN
  SQL (0.8ms)  INSERT INTO "searches" ("amenity_id", "boro_id", "created_at", "keywords", "listing_type_id", "max_price", "min_price", "neighborhood_id", "num_bathrooms", "num_bedrooms", "property_type_id", "square_footage", "updated_at") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13) RETURNING "id"  [["amenity_id", nil], ["boro_id", nil], ["created_at", Wed, 06 Mar 2013 09:09:55 UTC +00:00], ["keywords", nil], ["listing_type_id", nil], ["max_price", nil], ["min_price", nil], ["neighborhood_id", nil], ["num_bathrooms", nil], ["num_bedrooms", nil], ["property_type_id", nil], ["square_footage", nil], ["updated_at", Wed, 06 Mar 2013 09:09:55 UTC +00:00]]
   (32.2ms)  COMMIT
Redirected to http://localhost:3000/searches/29

Answer 1

The select2 plugin supports auto-completion. You can use the native auto-completion as follows:

<%= f.input_field :ac_neighborhood_ids, 
      data: { 
        placeholder: "Where do you want to live?",
        saved: @search.neighborhoods.to_json,
        url: autocomplete_neighborhood_name_searches_path
      }, 
      input_html:  { class: "span8 ac-select2" }
%>

Javscript

$(document).ready(function() {  
  $('.ac-select2').each(function() {
    var url = $(this).data('url'); 
    var placeholder = $(this).data('placeholder'); 
    var saved = jQuery.parseJSON($(this).data('saved'));
    $(this).select2({
      minimumInputLength: 2,
      multiple: true,
      placeholder : placeholder,
      allowClear: true,
      ajax: {
        url: url,
        dataType: 'json',
        quietMillis: 500,
        data: function (term) {
          return {
            name: term
          };
        },
        results: function (data) {
          return {results: data};
        }
      },

      formatResult: function (item, page) {
        return item.name; 
      },

      formatSelection: function (item, page) {
        return item.name; 
      },

      initSelection : function (element, callback) {
        if (saved) {
          callback(saved);
        }
      }

    });
  });
});

Make sure the action at autocomplete_neighborhood_name_searches_path returns a json array of hashes. Each hash should contain id and name fields. The term for auto-completion is passed via the query parameter name.

  def autocomplete_neighborhood_name
    @neighborhood = Neighborhood.select("id, name").where("name LIKE ?", "#{params[:name]}%").order(:name).limit(10)

    respond_to do |format|
      format.json { render json: @neighborhood , :only => [:id, :name] }
    end    
  end

Your search model:

class Search

  attr_accessor :ac_neighborhood_ids

  has_many :search_neighborhoods
  has_many :neighborhoods, through: :search_neighborhoods

  def ac_neighborhood_ids
    neighborhood_ids.join(",")
  end

  def ac_neighborhoods
    neighborhoods.map{|n| {:id => n.id, :name => n.name}}
  end

  def ac_neighborhood_ids=(ids)
    search_neighborhoods.clear # remove the old values
    ids.split(',').select(&:present?).map do |neighborhood_id|
      search_neighborhoods.build neighborhood_id: neighborhood_id
    end
  end

end