我如何引用我的友谊表有条件地显示code？ [英] How do I reference my Friendships table to conditionally display code?

问题描述

我已经成功地为用户建立了友谊自我的借鉴协会在我的Ruby on Rails应用程序下面的 Ryan Ba​​tes的railscast 。我可以成功地跟随，停止追随，并查看谁在下面。现在，我想在另一个元素拉，我不知道该怎么做。

在我的仪表盘CURRENT_USER页面上我希望有条件地显示基于CURRENT_USER与否的元素下面的人，如果CURRENT_USER被后面的人。在oother也就是说，如果CURRENT_USER没有关注任何人，我不希望显示以下内容：

 ＆LT; D​​IV ID =下面的类=＆GT;
 ＆LT; H2类=TK-约翰母鹿＆GT;继＆LT; / H＆GT;
 ＆LT;％的友谊@ user.friendships％GT;
  ＆LT; D​​IV CLASS =朋友＆GT;
   ＆所述;％=的link_to（friendship.friend.username），friendship.friend％GT; ＆LT;％=的link_to（取消关注），友谊：方法=＆GT; ：删除：类=＆GT; 取消关注％GT;
   ＆LT; / DIV＆GT; ＆LT;！ - ＃接近 - ＆GT;
 ＆LT;％结束％GT;
＆LT; / DIV＆GT; ＆LT;！ - ＃接近 - ＆GT;
 

和如果CURRENT_USER没有被随后的人我不想显示此

 ＆LT; D​​IV ID =之后，你级=grid_4阿尔法＆GT;
  ＆LT; H2类=TK-约翰母鹿＆GT;关注＆LT; / H＆GT;
  ＆LT;％的用户@ user.inverse_friends％GT;
    ＆LT; D​​IV CLASS =朋友＆GT;
      ＆LT;％=的link_to（user.username），用户％GT;
    ＆LT; / DIV＆GT; ＆LT;！ - ＃接近 - ＆GT;
  ＆LT;％结束％GT;
 ＆LT; / DIV＆GT; ＆LT;！ - ＃接近 - ＆GT;
 

这是协会如何设置：

Friendship.rb

  belongs_to的：用户
  belongs_to的：朋友：CLASS_NAME =＆GT; 用户
 

User.rb

 的has_many：友谊
  的has_many：朋友：通过=＆GT; ：友谊
  的has_many：inverse_friendships，：CLASS_NAME =＆GT; 友谊，：foreign_key =＆GT; friend_id
  的has_many：inverse_friends，：通过=＆GT; ：inverse_friendships，：源=＆GT; ：用户  高清friends_workouts
    @friends_workouts || = Workout.find_all_by_user_id（self.friends.map（安培;：ID）：为了=＆gt;中created_at DESC：极限=＆GT; 3）
  结束
 

解决方案

您可以检查是否有任何朋友或inversed_friends与方法的？
如果有一个或多个相关的记录它会返回true，否则这将是错误的。

 ＆LT;％@如果user.friends.any？ ％GT;
＆LT; D​​IV ID =下面的类=＆GT;
＆LT;！ - 内容 - ＆GT;
＆LT; / DIV＆GT;
＆LT;％结束％GT;
 

你可以做inverse_friends同样的事情

 ＆LT;％@如果user.inverse_friends.any？ ％GT;
 

I have successfully set up a friendship self referencial association for users in my Ruby on Rails app after following Ryan Bates' railscast. I can successfully follow, unfollow, and view who is following. Now I want to pull in another element and I am not sure how to do it.

When on my current_user dashboard page I want to conditionally display an element based on whether or not the current_user is following anyone and if the current_user is being followed by anyone. In oother words, if the current_user is not following anyone I don't want to display the following:

<div id="following" class="">
 <h2 class="tk-john-doe">Following</h2>
 <% for friendship in @user.friendships %>
  <div class="friend">
   <%= link_to (friendship.friend.username), friendship.friend %> <%= link_to "(Unfollow)", friendship, :method => :delete, :class => "unfollow" %>
   </div> <!-- close # -->
 <% end %>
</div> <!-- close # -->

And if the current_user is not being followed by anyone I don't want to display this:

<div id="following-you" class="grid_4 alpha">
  <h2 class="tk-john-doe">Followers</h2>
  <% for user in @user.inverse_friends %>
    <div class="friend">
      <%= link_to (user.username), user %>
    </div> <!-- close # -->
  <% end %>
 </div> <!-- close # -->

These are how the associations are set up:

Friendship.rb

  belongs_to :user
  belongs_to :friend, :class_name => "User"

User.rb

  has_many :friendships
  has_many :friends, :through => :friendships
  has_many :inverse_friendships, :class_name => "Friendship", :foreign_key => "friend_id"
  has_many :inverse_friends, :through => :inverse_friendships, :source => :user

  def friends_workouts
    @friends_workouts ||= Workout.find_all_by_user_id(self.friends.map(&:id), :order => "created_at DESC", :limit => 3)
  end

解决方案

You can check if there are any friends or inversed_friends with the method any? It will return true if there are one or more records associated, otherwise it will be false

<% if @user.friends.any? %>
<div id="following" class="">
<!-- content -->
</div>
<% end %>

And you can do the exact same thing with inverse_friends

<% if @user.inverse_friends.any? %>

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