Ruby on rails 如何根据asc/desc排序显示箭头（RoR 4）

正如标题所说，我试图显示向上/向下箭头。目前正在Ruby 2.0/Rails 4.0上构建

我跟随railscasts对表列进行排序（），但他当然使用表，所以他的箭头显示得很好

我想使用div/span/其他任何东西。（这不是很多数据，也不是需要放在表中的那种数据。）

也就是说，我为我的箭头创建了一个应用程序助手方法，它们可以工作，但是如果我为asc单击一个，两个箭头都指向上。如果我为desc单击一个，两个都指向下。显然，因为

params[：direction]

被设置为asc或desc，所以两个箭头都被设置。我怎样把它们分开？在一些伪代码中：

if title && asc
  sort by title and asc && show up arrow (for title only)
if title && desc
  sort by title and desc && show down arrow (for title only)
if date posted && asc
  sort by created_by and asc && show up arrow (for date posted only)
etc.

我真的不想有一个巨大的if/then条件语句，但我想要一些更简单的语句

（如果有必要的话，我会用一张桌子作为分类依据：部分，但这看起来真的非常愚蠢，这是最后的手段……）

以下是我得到的代码：

show.html.erb

<h3>Images</h3>
<% if @user.images.any? %>
  <div class="sortable"><%= sortable "img_name", "Title" %><%= arrow %> | 
                        <%= sortable "created_at", "Date posted" %><%= arrow %>
  </div>  
  <%= render @images %>
  <%= will_paginate @images %>
<% end %>

def sortable(column, title = nil)
    title ||=  column.titleize
    css_class = column == sort_column ? "current #{sort_direction}" : nil
    direction = column == sort_column && sort_direction == "asc" ? "desc" : "asc"
    link_to title, {sort: column, direction:  direction}, {class: css_class} 
end

def arrow
    if params[:direction] == 'asc'
        image_tag("arrow_up.png", alt: "up arrow", size: "15x15")
    elsif params[:direction] == 'desc'
        image_tag("arrow_down.png", alt: "down arrow", size: "15x15")
    else
        # either a blank image to show or just force no-display of image
    end
end

def show
  @user = User.find(params[:id])
  @images = @user.images.paginate(page: params[:page]).order(sort_column + " " + sort_direction)
end
private
  def sort_column
    Image.column_names.include?(params[:sort]) ? params[:sort] : "created_at"
  end

  def sort_direction
    %w[asc desc].include?(params[:direction]) ? params[:direction] : "asc"
  end

def sortable(column, title = nil)
  title ||= column.titleize
  css_class = column == sort_column ? "current #{sort_direction}" : nil
  direction = column == sort_column && sort_direction == 'asc' ? 'desc' : 'asc'

  capture do
    link_to({sort: column, direction: direction}, {class: css_class}) do
      concat title
      concat " "
      concat arrow(column)
    end
  end
end

def arrow(column)
  return '' if params[:sort] != column
  arrow = params[:direction] == 'asc' ? 'down' : 'up'
  "<i class='fa fa-caret-#{arrow}'></i>".html_safe
end

<%= sortable "img_name", "Title" %>

用户\u控制器.rb

<h3>Images</h3>
<% if @user.images.any? %>
  <div class="sortable"><%= sortable "img_name", "Title" %><%= arrow %> | 
                        <%= sortable "created_at", "Date posted" %><%= arrow %>
  </div>  
  <%= render @images %>
  <%= will_paginate @images %>
<% end %>

def sortable(column, title = nil)
    title ||=  column.titleize
    css_class = column == sort_column ? "current #{sort_direction}" : nil
    direction = column == sort_column && sort_direction == "asc" ? "desc" : "asc"
    link_to title, {sort: column, direction:  direction}, {class: css_class} 
end

def arrow
    if params[:direction] == 'asc'
        image_tag("arrow_up.png", alt: "up arrow", size: "15x15")
    elsif params[:direction] == 'desc'
        image_tag("arrow_down.png", alt: "down arrow", size: "15x15")
    else
        # either a blank image to show or just force no-display of image
    end
end

def show
  @user = User.find(params[:id])
  @images = @user.images.paginate(page: params[:page]).order(sort_column + " " + sort_direction)
end
private
  def sort_column
    Image.column_names.include?(params[:sort]) ? params[:sort] : "created_at"
  end

  def sort_direction
    %w[asc desc].include?(params[:direction]) ? params[:direction] : "asc"
  end

def sortable(column, title = nil)
  title ||= column.titleize
  css_class = column == sort_column ? "current #{sort_direction}" : nil
  direction = column == sort_column && sort_direction == 'asc' ? 'desc' : 'asc'

  capture do
    link_to({sort: column, direction: direction}, {class: css_class}) do
      concat title
      concat " "
      concat arrow(column)
    end
  end
end

def arrow(column)
  return '' if params[:sort] != column
  arrow = params[:direction] == 'asc' ? 'down' : 'up'
  "<i class='fa fa-caret-#{arrow}'></i>".html_safe
end

<%= sortable "img_name", "Title" %>

---

我不理解你不愿意在这里用桌子。即使是一个小表，这仍然是表格数据，包含行、列和标题。为什么要用类似于表的div结构替换语义表结构

也就是说，我将扩展arrow帮助程序以发送箭头用于哪个列：

def arrow(column)
  # as you're not sorting on the column, you don't want to see the arrow at
  # all of the header is not for the sorted column
  return '' if params[:sort] != column
  # ...
end

导致模板看起来像：

<%= sortable "img_name", "Title" %><%= arrow "img_name" %>

产生更简单的模板：

<%= sortable "img_name", "Title" %>

---

如果其他人想使用glyphicon而不是像我这样的图像，这个解决方案可能会很有用。在这个例子中，我使用

应用程序\u helper.rb

<h3>Images</h3>
<% if @user.images.any? %>
  <div class="sortable"><%= sortable "img_name", "Title" %><%= arrow %> | 
                        <%= sortable "created_at", "Date posted" %><%= arrow %>
  </div>  
  <%= render @images %>
  <%= will_paginate @images %>
<% end %>

def sortable(column, title = nil)
    title ||=  column.titleize
    css_class = column == sort_column ? "current #{sort_direction}" : nil
    direction = column == sort_column && sort_direction == "asc" ? "desc" : "asc"
    link_to title, {sort: column, direction:  direction}, {class: css_class} 
end

def arrow
    if params[:direction] == 'asc'
        image_tag("arrow_up.png", alt: "up arrow", size: "15x15")
    elsif params[:direction] == 'desc'
        image_tag("arrow_down.png", alt: "down arrow", size: "15x15")
    else
        # either a blank image to show or just force no-display of image
    end
end

def show
  @user = User.find(params[:id])
  @images = @user.images.paginate(page: params[:page]).order(sort_column + " " + sort_direction)
end
private
  def sort_column
    Image.column_names.include?(params[:sort]) ? params[:sort] : "created_at"
  end

  def sort_direction
    %w[asc desc].include?(params[:direction]) ? params[:direction] : "asc"
  end

def sortable(column, title = nil)
  title ||= column.titleize
  css_class = column == sort_column ? "current #{sort_direction}" : nil
  direction = column == sort_column && sort_direction == 'asc' ? 'desc' : 'asc'

  capture do
    link_to({sort: column, direction: direction}, {class: css_class}) do
      concat title
      concat " "
      concat arrow(column)
    end
  end
end

def arrow(column)
  return '' if params[:sort] != column
  arrow = params[:direction] == 'asc' ? 'down' : 'up'
  "<i class='fa fa-caret-#{arrow}'></i>".html_safe
end

<%= sortable "img_name", "Title" %>

def可排序（列，标题=nil）
title | |=column.titleize
css\u class=column==sort\u column？“当前#{sort_direction}”：无
方向=列==排序\列和排序\方向=='asc'？'描述：'asc'
俘获
链接到（{sort:column，direction:direction}，{class:css\u class}）do
康卡特头衔
海螺“
concat箭头（列）
结束
结束
结束
def箭头（列）
如果参数[：排序]！=柱
箭头=参数[：方向]=“asc”？”向下“：“向上”
“”.html\u安全
结束

show.html.erb

<h3>Images</h3>
<% if @user.images.any? %>
  <div class="sortable"><%= sortable "img_name", "Title" %><%= arrow %> | 
                        <%= sortable "created_at", "Date posted" %><%= arrow %>
  </div>  
  <%= render @images %>
  <%= will_paginate @images %>
<% end %>

def sortable(column, title = nil)
    title ||=  column.titleize
    css_class = column == sort_column ? "current #{sort_direction}" : nil
    direction = column == sort_column && sort_direction == "asc" ? "desc" : "asc"
    link_to title, {sort: column, direction:  direction}, {class: css_class} 
end

def arrow
    if params[:direction] == 'asc'
        image_tag("arrow_up.png", alt: "up arrow", size: "15x15")
    elsif params[:direction] == 'desc'
        image_tag("arrow_down.png", alt: "down arrow", size: "15x15")
    else
        # either a blank image to show or just force no-display of image
    end
end

def show
  @user = User.find(params[:id])
  @images = @user.images.paginate(page: params[:page]).order(sort_column + " " + sort_direction)
end
private
  def sort_column
    Image.column_names.include?(params[:sort]) ? params[:sort] : "created_at"
  end

  def sort_direction
    %w[asc desc].include?(params[:direction]) ? params[:direction] : "asc"
  end

def sortable(column, title = nil)
  title ||= column.titleize
  css_class = column == sort_column ? "current #{sort_direction}" : nil
  direction = column == sort_column && sort_direction == 'asc' ? 'desc' : 'asc'

  capture do
    link_to({sort: column, direction: direction}, {class: css_class}) do
      concat title
      concat " "
      concat arrow(column)
    end
  end
end

def arrow(column)
  return '' if params[:sort] != column
  arrow = params[:direction] == 'asc' ? 'down' : 'up'
  "<i class='fa fa-caret-#{arrow}'></i>".html_safe
end

<%= sortable "img_name", "Title" %>

Hm，我试过这个，但没有成功。两支箭仍然同时指向上或下。我决定只为排序链接创建一个表，并尝试以这种方式工作：一旦我让它完全工作，我会发布我的解决方案。我想你一定错过了什么（或者我错过了什么）。请注意箭头辅助对象中的第一行。应该只有一个箭头，即当前正在排序的列的箭头。如果列不是要排序的列，则返回空字符串而不是图像标记。