max_csv_records = 2000 (fixed to work with lastest activedadmin)

Gemfile.lock

@@ -2,7 +2,7 @@ PATH
   remote: .
   specs:
     activeadmin-axlsx (3.0.0)
-      activeadmin (~> 0.6.0)
+      activeadmin (>= 1.0.0.pre2)
       axlsx
 
 GEM

activeadmin-axlsx.gemspec

@@ -13,11 +13,11 @@ Gem::Specification.new do |s|
   s.description = <<-eof
   This gem uses axlsx to provide excel/xlsx downloads for resources in Active Admin. Often, users are happier with excel, so why not give it to them instead of CSV?
   eof
-  s.files       = `git ls-files`.split("\n").sort 
+  s.files       = `git ls-files`.split("\n").sort
   s.test_files  = `git ls-files -- {spec}/*`.split("\n")
   s.test_files  = Dir.glob("{spec/**/*}")
 
-  s.add_runtime_dependency 'activeadmin', "~> 0.6.0"
+  s.add_runtime_dependency 'activeadmin', ">= 1.0.0.pre2"
   s.add_runtime_dependency 'axlsx'
 
   s.required_ruby_version = '>= 1.9.2'

lib/active_admin/axlsx.rb

@@ -15,15 +15,9 @@ class Railtie < ::Rails::Railtie
     rescue NameError
       # noop
     end
-
-  end
-
-  config.after_initialize do
     ActiveAdmin::ResourceDSL.send :include, ActiveAdmin::Axlsx::DSL
     ActiveAdmin::Resource.send :include, ActiveAdmin::Axlsx::ResourceExtension
     ActiveAdmin::Views::PaginatedCollection.add_format :xlsx
     ActiveAdmin::ResourceController.send :include, ActiveAdmin::Axlsx::ResourceControllerExtension
   end
 end
-
-

lib/active_admin/axlsx/resource_controller_extension.rb

@@ -1,15 +1,17 @@
 module ActiveAdmin
   module Axlsx
     module ResourceControllerExtension
+
       def self.included(base)
-        base.send :alias_method_chain, :per_page, :xlsx
-        base.send :alias_method_chain, :index, :xlsx
+        # base.send :alias_method_chain, :per_page, :xlsx
+        # base.send :alias_method_chain, :index, :xlsx
+        base.preprend(ResourceControllerExtension)
         base.send :respond_to, :xlsx
       end
 
       # patching the index method to allow the xlsx format.
-      def index_with_xlsx(options={}, &block)
-        index_without_xlsx(options) do |format|
+      def index(&block)
+        index_without_xlsx do |format|
            format.xlsx do
             xlsx = active_admin_config.xlsx_builder.serialize(collection)
             send_data xlsx, :filename => "#{xlsx_filename}", :type => Mime::Type.lookup_by_extension(:xlsx)
@@ -18,11 +20,12 @@ def index_with_xlsx(options={}, &block)
       end
 
       # patching per_page to use the CSV record max for pagination when the format is xlsx
-      def per_page_with_xlsx
-          if request.format ==  Mime::Type.lookup_by_extension(:xlsx)
-            return max_csv_records
-          end
-          per_page_without_xlsx
+      def per_page
+        max_csv_records = 2000
+        if request.format ==  Mime::Type.lookup_by_extension(:xlsx)
+          return max_csv_records
+        end
+        per_page_without_xlsx
       end
 
       # Returns a filename for the xlsx file using the collection_name