我是 Rails 新手，我想知道如何按特定列进行分页和排序。我可以在一个表中执行此操作，但是当有多个表并且排序列不在主表中时。
我试了很多次都失败了，我也在网上搜索过，也是徒劳。现在我需要你的帮助......请帮助！
虽然分页我正在使用这个：
# encoding: utf-8
module Pagination
class Paginator
attr_reader :item_count, :per_page, :page, :page_param
def initialize(*args)
if args.first.is_a?(ActionController::Base)
args.shift
ActiveSupport::Deprecation.warn "Paginator no longer takes a controller instance as the first argument. Remove it from #new arguments."
end
item_count, per_page, page, page_param = *args
@item_count = item_count
@per_page = per_page
page = (page || 1).to_i
if page < 1
page = 1
end
@page = page
@page_param = page_param || :page
end
def offset
(page - 1) * per_page
end
def first_page
if item_count > 0
1
end
end
def previous_page
if page > 1
page - 1
end
end
def next_page
if last_item < item_count
page + 1
end
end
def last_page
if item_count > 0
(item_count - 1) / per_page + 1
end
end
def first_item
item_count == 0 ? 0 : (offset + 1)
end
def last_item
l = first_item + per_page - 1
l > item_count ? item_count : l
end
def linked_pages
pages = []
if item_count > 0
pages += [first_page, page, last_page]
pages += ((page-2)..(page+2)).to_a.select {|p| p > first_page && p < last_page}
end
pages = pages.compact.uniq.sort
if pages.size > 1
pages
else
[]
end
end
def items_per_page
ActiveSupport::Deprecation.warn "Paginator#items_per_page will be removed. Use #per_page instead."
per_page
end
def current
ActiveSupport::Deprecation.warn "Paginator#current will be removed. Use .offset instead of .current.offset."
self
end
end
# Paginates the given scope or model. Returns a Paginator instance and
# the collection of objects for the current page.
#
# Options:
# :parameter name of the page parameter
#
# Examples:
# @user_pages, @users = paginate User.where(:status => 1)
#
def paginate(scope, options={})
options = options.dup
finder_options = options.extract!(
:conditions,
:order,
:joins,
:include,
:select
)
if scope.is_a?(Symbol) || finder_options.values.compact.any?
return deprecated_paginate(scope, finder_options, options)
end
paginator = paginator(scope.count, options)
collection = scope.limit(paginator.per_page).offset(paginator.offset).to_a
return paginator, collection
end
def deprecated_paginate(arg, finder_options, options={})
ActiveSupport::Deprecation.warn "#paginate with a Symbol and/or find options is depreceted and will be removed. Use a scope instead."
klass = arg.is_a?(Symbol) ? arg.to_s.classify.constantize : arg
scope = klass.scoped(finder_options)
paginate(scope, options)
end
def paginator(item_count, options={})
options.assert_valid_keys :parameter, :per_page
page_param = options[:parameter] || :page
page = (params[page_param] || 1).to_i
per_page = options[:per_page] || per_page_option
Paginator.new(item_count, per_page, page, page_param)
end
module Helper
include Redmine::I18n
# Renders the pagination links for the given paginator.
#
# Options:
# :per_page_links if set to false, the "Per page" links are not rendered
#
def pagination_links_full(*args)
pagination_links_each(*args) do |text, parameters, options|
if block_given?
yield text, parameters, options
else
link_to text, params.merge(parameters), options
end
end
end
# Yields the given block with the text and parameters
# for each pagination link and returns a string that represents the links
def pagination_links_each(paginator, count=nil, options={}, &block)
options.assert_valid_keys :per_page_links
per_page_links = options.delete(:per_page_links)
per_page_links = false if count.nil?
page_param = paginator.page_param
html = ''
if paginator.previous_page
# \xc2\xab(utf-8) = «
text = "\xc2\xab " + l(:label_previous)
html << yield(text, {page_param => paginator.previous_page}, :class => 'previous') + ' '
end
previous = nil
paginator.linked_pages.each do |page|
if previous && previous != page - 1
html << content_tag('span', '...', :class => 'spacer') + ' '
end
if page == paginator.page
html << content_tag('span', page.to_s, :class => 'current page')
else
html << yield(page.to_s, {page_param => page}, :class => 'page')
end
html << ' '
previous = page
end
if paginator.next_page
# \xc2\xbb(utf-8) = »
text = l(:label_next) + " \xc2\xbb"
html << yield(text, {page_param => paginator.next_page}, :class => 'next') + ' '
end
html << content_tag('span', "(#{paginator.first_item}-#{paginator.last_item}/#{paginator.item_count})", :class => 'items') + ' '
if per_page_links != false && links = per_page_links(paginator, &block)
html << content_tag('span', links.to_s, :class => 'per-page')
end
html.html_safe
end
# Renders the "Per page" links.
def per_page_links(paginator, &block)
values = per_page_options(paginator.per_page, paginator.item_count)
if values.any?
links = values.collect do |n|
if n == paginator.per_page
content_tag('span', n.to_s)
else
yield(n, :per_page => n, paginator.page_param => nil)
end
end
l(:label_display_per_page, links.join(', ')).html_safe
end
end
def per_page_options(selected=nil, item_count=nil)
options = Setting.per_page_options_array
if item_count && options.any?
if item_count > options.first
max = options.detect {|value| value >= item_count} || item_count
else
max = item_count
end
options = options.select {|value| value <= max || value == selected}
end
if options.empty? || (options.size == 1 && options.first == selected)
[]
else
options
end
end
end
end
end