# 為什麽在安裝PaperClip時會得到“has_attached_file”的“未定義方法”？

NoMethodError (undefined method has_attached_file' for #):
app/models/post.rb:2
app/controllers/posts_controller.rb:50:in show'


It is referencing the will_paginate gem. From what I can find, it seems that either there is something wrong with my PostsController#index or perhaps a previously attempt at installing the gem instead of the plugin, in which case I have read I should be able to remedy through the /config/environments.rb file somehow.

I didn't think that previous gem installation would matter as I did it in an old version of the site that I trashed before installing the plugin. In the current version of the site I show that the table has been updated with the Paperclip columns after migration. Here is my code:

PostsConroller#show:

  def show
@post = Post.find(params[:id])

respond_to do |format|
format.html # show.html.erb
format.xml  { render :xml => @post }
end
end


Post model:

class Post < ActiveRecord::Base

has_attached_file :photo
validates_presence_of :body, :title
has_many :tags, :dependent => :destroy
belongs_to :user
after_create :self_vote
def self_vote
# I am assuming you have a user_id field in posts and votes table.
end

@@per_page = 10

end


/views/posts/new.html.erb:

# New post

 { :multipart => true}) do |f| %>

`