# app/admin/post.rb
ActiveAdmin.register Post do
  permit_params :title, :content, :category_id 
  form do |f|
    f.inputs "Details" do
      f.input :title
      f.input :content, as: :text
      f.input :category
    end
    actions
  end
end
add_new_record_button.js// app/assets/javascripts/add_new_record_button.js
(function() {
  $(function() {
    $('select[data-has-new-option=true]').select2({
      placeholder: "选择或新建记录",
      allowClear: true,
      tags: true,
      createTag: function (params) {
        var term = $.trim(params.term);
        if (term === '') {
          return null;
        }
        return {
          id: term,
          text: term,
          newOption: true
        }
      }
    }).on('select2:select', function (e) {
      if (e.params.data.newOption) {
        var $option = $("")
          .val(e.params.data.id)
          .text(e.params.data.text);
        $(this).append($option).trigger('change');
      }
    });
  });
}).call(this);
# app/assets/javascripts/active_admin.js
//= require active_admin/base
//= require add_new_record_button
# app/admin/category.rb
ActiveAdmin.register Category do
  permit_params :name
end
完成这些步骤后,便可以实现添加关联数据的“添加新记录”按钮,用户可以选择现有关联资源或创建新的关联资源。