Dynamic Select Menus for Rails 3

Guys help me please. How to convert this rails-cast to rails 3 ? I'm
trying to convert it but still there is no luck.

http://railscasts.com/episodes/88-dynamic-select-menus

Thanks in Advanced. c",)

Are you using jQuery or Prototype in the rest of your app? The code on this 'cast is Prototype, so the only differences you will need to cover are in that realm. Everything else should just work.

Walter

Hi,

I also want a dynamic select menu but I want use jQuery and in my case
it doesn't works (I follow a different sly verano's tutorial) follow all
my steps

NOTE: I want use a list of data from a database

HOW CREATE the MODELS

$ rails generate model basket shape:string
$ rails generate model apple color:string shape_id:integer
$ rails generate model table basket:string apple:string

populate the database with a migration

$ rails generate migration create_hierarchy

/db/20120306193843_create_hierarchy.rb

class CreateHierarchy< ActiveRecord::Migration
  def self.up
    g1 = Basket.create(:shape => "awesome")
    g2 = Basket.create(:shape => "normal")

    a1 = Apple.create(:color => "Green", :basket_id => g1.id)
    a2 = Apple.create(:color => "Reds", :basket_id => g1.id)
    a3 = Apple.create(:color => "White", :basket_id => g2.id)
    a4 = Apple.create(:color => "Purple", :basket_id => g2.id)

  end

  def self.down
# you can fill this in if you want.
  end
end

MODELS

I have 3 model @table, @basket, @apple

class Apple
    belongs_to :tables
    belongs_to: baskets
end

class Basket
    belongs_to :tables
    has_many :apples
end

class Table
    has_many :baskets
    has_many :apples
end

CONTROLLER

in the @table controller I have

def index
    @basket = Basket.find(:all)
    @apple = Apple.find(:all)
    @table = Table.new
  end

VIEWS

the form is in app/views/tables/index.html.erb file

<%= form_for @table do |f| %>
<%= f.collection_select(:basket, @basket, :id, :shape, {:prompt =>true})
%>
<%= f.collection_select(:apple, @apple, :id, :color, {:prompt => true})
%>
<%= f.submit %>
<% end %>

IN THE ROUTES

root :to => 'table#index'

NOW when I load the page

http://localhost:3000

I have 2 list menu

{basket}

{apple}

**** jQuery ******

I use Rails 3.1 and this is my Gemfile I have

/////////////////////

source 'http://rubygems.org'

gem 'rails', '3.1.0'

gem 'sqlite3'

# Gems used only for assets and not required
# in production environments by default.
group :assets do
  gem 'sass-rails', " ~> 3.1.0"
  gem 'coffee-rails', "~> 3.1.0"
  gem 'uglifier'
end

gem 'jquery-rails'

group :test do
  # Pretty printed test output
  gem 'turn', :require => false
end
//////////////

in the app/assest/javascript/table.js.coffee I have

jQuery ->
  apple = $('#table_apple').html()
  console.log(apple)
  $('#table_basket').change ->
    basket = $('#table_basket :selected').text()
    options = $(apple).filter("[label=#{basket}]").html()
    console.log(options)
    if options
      $('#table_apple').html(options)
    else
      $('#table_apple').empty()

but this script doesn't work 'cause onchange the first one {basket} the
second one is empty!

I don't know where's my mistake

thanks a lot in advance,

C

Hi,

I also want a dynamic select menu but I want use jQuery and in my case
it doesn't works (I follow a different sly verano's tutorial) follow all
my steps

NOTE: I want use a list of data from a database

HOW CREATE the MODELS

$ rails generate model basket shape:string
$ rails generate model apple color:string shape_id:integer
$ rails generate model table basket:string apple:string

populate the database with a migration

$ rails generate migration create_hierarchy

/db/20120306193843_create_hierarchy.rb

class CreateHierarchy< ActiveRecord::Migration
def self.up
   g1 = Basket.create(:shape => "awesome")
   g2 = Basket.create(:shape => "normal")

   a1 = Apple.create(:color => "Green", :basket_id => g1.id)
   a2 = Apple.create(:color => "Reds", :basket_id => g1.id)
   a3 = Apple.create(:color => "White", :basket_id => g2.id)
   a4 = Apple.create(:color => "Purple", :basket_id => g2.id)

end

def self.down
# you can fill this in if you want.
end
end

MODELS

I have 3 model @table, @basket, @apple

class Apple
   belongs_to :tables
   belongs_to: baskets
end

class Basket
   belongs_to :tables
   has_many :apples
end

class Table
   has_many :baskets
   has_many :apples
end

CONTROLLER

in the @table controller I have

def index
   @basket = Basket.find(:all)
   @apple = Apple.find(:all)
   @table = Table.new
end

VIEWS

the form is in app/views/tables/index.html.erb file

<%= form_for @table do |f| %>
<%= f.collection_select(:basket, @basket, :id, :shape, {:prompt =>true})
%>
<%= f.collection_select(:apple, @apple, :id, :color, {:prompt => true})
%>
<%= f.submit %>
<% end %>

IN THE ROUTES

root :to => 'table#index'

NOW when I load the page

http://localhost:3000

I have 2 list menu

{basket}

{apple}

**** jQuery ******

I use Rails 3.1 and this is my Gemfile I have

/////////////////////

source 'http://rubygems.org'

gem 'rails', '3.1.0'

gem 'sqlite3'

# Gems used only for assets and not required
# in production environments by default.
group :assets do
gem 'sass-rails', " ~> 3.1.0"
gem 'coffee-rails', "~> 3.1.0"
gem 'uglifier'
end

gem 'jquery-rails'

group :test do
# Pretty printed test output
gem 'turn', :require => false
end
//////////////

in the app/assest/javascript/table.js.coffee I have

jQuery ->
apple = $('#table_apple').html()
console.log(apple)
$('#table_basket').change ->
   basket = $('#table_basket :selected').text()
   options = $(apple).filter("[label=#{basket}]").html()
   console.log(options)
   if options
     $('#table_apple').html(options)
   else
     $('#table_apple').empty()

but this script doesn't work 'cause onchange the first one {basket} the
second one is empty!

I don't know where's my mistake

thanks a lot in advance,

C

You cannot update the contents of a select using html() (which is similar to Prototype's update() function). The only way to alter the options of a select cross-browser is to do the following:

1. Make a structure of your new elements, something like:

  var newOptions = [['one','One'],['two', 'Two'],['three', 'Three']]

2. Remove all of the existing options:

  myPicker.options.length = 0;

3. Loop through your array of new options, and build them up one at a time into options on the now-empty picker:

  for(i = 0; i < newOptions.length; i++){
    myPicker.options[myPicker.options.length] = new Option(newOptions[i][0], newOptions[i][1];
  }

Hope this helps,

Walter

What exactly aren't you having luck with? Do you need help with the
JQuery conversion?
As Walter Lee said, Rails 3 defaults with JQuery now.

What exactly aren't you having luck with? Do you need help with the
JQuery conversion?

It sounds like he's using html() to replace the innards of a select list, and that doesn't usually work.

Walter

Thanks for the answers,

follow the source web page, I have:

<label for="table_basket">Basket</label>
<select id="table_basket" name="table[basket]"><option value="">Please
select</option>
<option value="1">Awesome</option>
<option value="2">Normal</option></select>

<label for="table_apple">Apple</label>
<select id="table_apple" name="table[apple]"><option value="">Please
select</option>
<option value="1">Green</option>
<option value="1">Red</option>
<option value="2">Yellow</option>
<option value="2">White</option></select>

<input name="commit" type="submit" value="Create Table" />

To works I have to pass the right variable in the follow line

options = $(apple).filter("[label=#{basket}]").html()

I think the problem is here: label=#{basket}] that variable gone be 1 o
2 (check out the option=value in <select id="table_apple"
name="table[apple]"> menu) this value is function of the Basket choice

well I think its only this the problem in the
app/assest/javascript/table.js.coffee file but I don't know if it's only
a
simple syntax error

jQuery ->
  apple = $('#table_apple').html()
  $('#table_basket').change ->
    basket = $('#table_basket :selected').text()
    options = $(apple).filter("[label=#{basket}]").html()
    if options
      $('#table_apple').html(options)
    else
      $('#table_apple').empty()

thanks a lot anyway

C

Thanks for the answers,

follow the source web page, I have:

<label for="table_basket">Basket</label>
<select id="table_basket" name="table[basket]"><option value="">Please
select</option>
<option value="1">Awesome</option>
<option value="2">Normal</option></select>

<label for="table_apple">Apple</label>
<select id="table_apple" name="table[apple]"><option value="">Please
select</option>
<option value="1">Green</option>
<option value="1">Red</option>
<option value="2">Yellow</option>
<option value="2">White</option></select>

<input name="commit" type="submit" value="Create Table" />

To works I have to pass the right variable in the follow line

options = $(apple).filter("[label=#{basket}]").html()

I think the problem is here: label=#{basket}] that variable gone be 1 o
2 (check out the option=value in <select id="table_apple"
name="table[apple]"> menu) this value is function of the Basket choice

well I think its only this the problem in the
app/assest/javascript/table.js.coffee file but I don't know if it's only
a
simple syntax error

jQuery ->
apple = $('#table_apple').html()
$('#table_basket').change ->
   basket = $('#table_basket :selected').text()
   options = $(apple).filter("[label=#{basket}]").html()
   if options
     $('#table_apple').html(options)

You can't just do this, not unless behind the scenes, jQuery is imputing that the array is an array of select options, and that the target is a select, and is magic-ly and silently doing the Right Thing™ and building new Option objects and inserting them in the select. Really, I'm not kidding here, this is not going to work in any or many browsers.

I would love to be wrong about this, but as far as I know, you MUST:

1. Zero the length of the select object.
2. One at a time, create a new Option object, assign it the desired value and text, and add it to the select's options array.

After you have done those things, in that order, you will have a working select with the new options.

I know it doesn't look cool to have that old-school bare JavaScript hanging out in your CoffeeScript, but really, needs must.

   else
     $('#table_apple').empty()

thanks a lot anyway

You're welcome,

Walter

thanks for your answer

even if I don't speak a perfect english I really appreciate your answer
only I hope to understand your effort

thanks a lot again

C