如何使用Haml和Formtastic动态添加和删除嵌套模型字段

Question

我们都看到了辉煌的复杂形式railscast,其中Ryan Bates解释了如何使用Javascript在父对象表单中动态添加或删除嵌套对象.

有没有人对如何修改这些方法以便与Haml Formtastic合作有任何想法？

在这里添加一些上下文是我目前面临的问题的简化版本:

#教师表格(有嵌套的主题表格)[来自我的申请]

- semantic_form_for(@teacher) do |form|
  - form.inputs do
    = form.input :first_name
    = form.input :surname
    = form.input :city
    = render 'subject_fields', :form => form 
    = link_to_add_fields "Add Subject", form, :subjects   

#个人主题形式部分[来自我的申请]

- form.fields_for :subjects do |ff| 
  #subject_field
    = ff.input :name
    = ff.input :exam
    = ff.input :level
    = ff.hidden_field :_destroy
    = link_to_remove_fields "Remove Subject", ff 

#Application Helper(直接来自Railscasts)

  def link_to_remove_fields(name, f)
    f.hidden_field(:_destroy) + link_to_function(name, "remove_fields(this)")
  end

  def link_to_add_fields(name, f, association)
    new_object = f.object.class.reflect_on_association(association).klass.new
    fields = f.fields_for(association, new_object, :child_index => "new_#{association}") do |builder|
      render(association.to_s.singularize + "_fields", :f => builder)
    end
    link_to_function(name, h("add_fields(this, \"#{association}\", \"#{escape_javascript(fields)}  \")"))
  end

#Application.js(直接来自Railscasts)

  function remove_fields(link) {
  $(link).previous("input[type=hidden]").value = "1";
  $(link).up(".fields").hide();
  }

function add_fields(link, association, content) {
  var new_id = new Date().getTime();
  var regexp = new RegExp("new_" + association, "g")
  $(link).up().insert({
    before: content.replace(regexp, new_id)
  });
  }

实现的问题似乎与javascript方法有关 - Formtastic形式的DOM树与常规rails形式有很大不同.

我已经在网上看过几次这个问题,但还没有找到答案 - 现在你知道帮助将不仅仅是我的赞赏!

插口

Answer 1

你走在正确的轨道上:

... Formtastic形式的DOM树与常规轨道形式有很大不同.

为了使Ryan的示例适用于formtastic,提醒semantic_fields_for帮助器类似于帮助器是有semantic_form_for帮助的,它以列表形式输出输入.

为了使事情尽可能接近Railscast代码,您需要:

• 在包装器中包含嵌套字段的集合(我使用带有subjectsCSS ID 的div .)
• 将嵌套字段包含在ul/ol包装器中(我应用了一个nested-fieldsCSS类.)

这是你的文件应该是什么样的.

教师表单(具有嵌套的主题字段):

- semantic_form_for(@teacher) do |form|
  - form.inputs do
    = form.input :first_name
    = form.input :surname
    = form.input :city

    %h2 Subjects
    #subjects
      - form.semantic_fields_for :subjects do |builder|
        = render :partial => "subject_fields", :locals => { :f => builder }
      .links
        = link_to_add_fields "Add Subject", form, :subjects

主题字段部分(对于嵌套主题):

%ul.nested-fields
  = f.input :name
  = f.input :exam
  = f.input :level
  = link_to_remove_fields "Remove Subject", f

ApplicationHelper:

def link_to_remove_fields(name, f)
  f.hidden_field(:_destroy) + link_to_function(name, "remove_fields(this)")
end

def link_to_add_fields(name, f, association)
  new_object = f.object.class.reflect_on_association(association).klass.new
  fields = f.fields_for(association, new_object, :child_index => "new_#{association}") do |builder|
    render(association.to_s.singularize + "_fields", :f => builder)
  end
  link_to_function(name, h("add_fields(this, \"#{association}\", \"#{escape_javascript(fields)}\")"))
end

application.js中:

function remove_fields(link) {
  $(link).previous("input[type=hidden]").value = "1";
  $(link).up(".nested-fields").hide();
}

function add_fields(link, association, content) {
  var new_id = new Date().getTime();
  var regexp = new RegExp("new_" + association, "g")
  $(link).up().insert({
    before: content.replace(regexp, new_id)
  });
}

使用以下宝石:

• formtastic(0.9.10)
• haml(3.0.2)
• 小黄瓜(1.0.26)
• 铁轨(2.3.5)