我有这个未定义的方法“名字”，它曾经工作过......我不知道我搞砸了什么......我需要你的帮助...
index.html.slim
.container
.row
.col-xs-12
h1.text-gray Tutorials
h4 Search by Title
=form_tag tutos_path, :method => 'get' do
=text_field_tag :search, params[:search]
=submit_tag "Search", class:'btn btn-default'
.col-xs-12
-if user_signed_in?
= link_to "Create a tuto", new_tuto_path, class:"btn btn-success"
#tutos.transitions-enabled
-@tutos.each do |tuto|
.box.panel-default
-if tuto.category.name == "Ruby"
= link_to(image_tag("select/ruby.png"), tuto_path(tuto))
-elsif tuto.category.name == "Rails 4"
= link_to(image_tag("select/rails4.png"), tuto_path(tuto))
-elsif tuto.category.name == "Rails 5"
= link_to(image_tag("select/rails5.png"), tuto_path(tuto))
-elsif tuto.category.name == "Heroku"
= link_to(image_tag("select/heroku.png"), tuto_path(tuto))
-elsif tuto.category.name == "AWS-Amazon"
= link_to(image_tag("select/aws.png"), tuto_path(tuto))
h3 = link_to tuto.title, tuto_path(tuto), class:"title-link"
h6
| Created by:
span<>
= tuto.user.full_name
br
span.glyphicon.glyphicon-heart
span<>
= tuto.get_upvotes.size
br
br
我的类别是在控制台中创建的：
Category Load (1.4ms) SELECT "categories".* FROM "categories"
=> #<ActiveRecord::Relation [#<Category id: 1, name: "Ruby", created_at: "2016-09-26 09:03:17", updated_at: "2016-09-26 09:03:17">, #<Category id: 2, name: "Rails 4", created_at: "2016-09-26 09:03:25", updated_at: "2016-09-26 09:03:25">, #<Category id: 3, name: "Rails 5", created_at: "2016-09-26 09:03:30", updated_at: "2016-09-26 09:03:30">, #<Category id: 4, name: "Heroku", created_at: "2016-09-26 09:03:35", updated_at: "2016-09-26 09:03:35">, #<Category id: 5, name: "AWS-Amazon", created_at: "2016-09-26 09:03:43", updated_at: "2016-09-26 09:03:43">]>
2.3.1 :002 >
tutos_controller.rb
class TutosController < ApplicationController
before_action :authenticate_user!, only: [:new, :create]
before_action :set_tuto, only: [:show, :edit, :update, :destroy, :upvote]
def index
@tutos = Tuto.all.includes(:user && :category)
@categories = Category.all
keyword_search
end
def show
@tuto = Tuto.find(params[:id])
@user = User.all
end
def new
@tuto = Tuto.new
end
def edit
end
def create
@tuto = Tuto.new(tuto_params)
@tuto.user_id = current_user.id
respond_to do |format|
if @tuto.save
flash[:success] = "Test"
format.html { redirect_to @tuto, notice: 'Tuto was successfully created.' }
format.json { render :show, status: :created, location: @tuto }
else
format.html { render :new }
format.json { render json: @tuto.errors, status: :unprocessable_entity }
end
end
end
def update
respond_to do |format|
if @tuto.update(tuto_params)
format.html { redirect_to @tuto, notice: 'Tuto was successfully updated.' }
format.json { render :show, status: :ok, location: @tuto }
else
format.html { render :edit }
format.json { render json: @tuto.errors, status: :unprocessable_entity }
end
end
end
def destroy
@tuto.destroy
respond_to do |format|
format.html { redirect_to tutos_url, notice: 'Tuto was successfully destroyed.' }
format.json { head :no_content }
end
end
def upvote
@tuto.upvote_by current_user
redirect_to :back
end
def keyword_search
@tutos = Tuto.search(params[:search])
end
private
def set_tuto
@tuto = Tuto.find(params[:id])
end
def tuto_params
params.require(:tuto).permit(:title, :content, :id, :user_id, :category_id)
end
end
架构
ActiveRecord::Schema.define(version: 20160920133801) do
create_table "categories", force: :cascade do |t|
t.string "name"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "tutos", force: :cascade do |t|
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.string "title"
t.text "content"
t.integer "user_id"
t.integer "category_id"
end
add_index "tutos", ["user_id"], name: "index_tutos_on_user_id"
create_table "users", force: :cascade do |t|
t.string "email", default: "", null: false
t.string "encrypted_password", default: "", null: false
t.string "reset_password_token"
t.datetime "reset_password_sent_at"
t.datetime "remember_created_at"
t.integer "sign_in_count", default: 0, null: false
t.datetime "current_sign_in_at"
t.datetime "last_sign_in_at"
t.string "current_sign_in_ip"
t.string "last_sign_in_ip"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.string "first_name"
t.string "last_name"
t.boolean "admin"
end
add_index "users", ["email"], name: "index_users_on_email", unique: true
add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
create_table "votes", force: :cascade do |t|
t.integer "votable_id"
t.string "votable_type"
t.integer "voter_id"
t.string "voter_type"
t.boolean "vote_flag"
t.string "vote_scope"
t.integer "vote_weight"
t.datetime "created_at"
t.datetime "updated_at"
end
add_index "votes", ["votable_id", "votable_type", "vote_scope"], name: "index_votes_on_votable_id_and_votable_type_and_vote_scope"
add_index "votes", ["voter_id", "voter_type", "vote_scope"], name: "index_votes_on_voter_id_and_voter_type_and_vote_scope"
end
tuto_model.rb
class Tuto < ActiveRecord::Base
acts_as_votable
belongs_to :user
belongs_to :category
validates :category_id, presence: true
def self.search(search)
if search
where(["title LIKE ?","%#{search}%"])
else
all
end
end
end
category_model.rb
class Category < ActiveRecord::Base
has_many :tutos
end
这是我对deepak建议的错误，（顺便说一句，我真的很喜欢他建议的重构!!）
index.html.slim:29: syntax error, unexpected ';', expecting ')' ...temple_html_pretty1)))).to_s)); ... ^
Extracted source (around line #29):
27
28
29
30
31
32
-@tutos.each do |tuto|
.box.panel-default
= link_to image_tag(image_by_category(tuto.category.try(:name)), tuto_path(tuto)
h3 = link_to tuto.title, tuto_path(tuto), class:"title-link"
答案 0 :(得分：2)
其中一个类别是nil，这就是你获得
未定义的方法＆＃34;名称＆＃34;为零：NilClass
使用try
<强> index.html.slim
-@tutos.each do |tuto|
.box.panel-default
-if tuto.category.try(:name) == "Ruby"
= link_to(image_tag("select/ruby.png"), tuto_path(tuto))
-elsif tuto.category.try(:name) == "Rails 4"
= link_to(image_tag("select/rails4.png"), tuto_path(tuto))
-elsif tuto.category.try(:name) == "Rails 5"
= link_to(image_tag("select/rails5.png"), tuto_path(tuto))
-elsif tuto.category.try(:name) == "Heroku"
= link_to(image_tag("select/heroku.png"), tuto_path(tuto))
-elsif tuto.category.try(:name) == "AWS-Amazon"
= link_to(image_tag("select/aws.png"), tuto_path(tuto))
此外，我建议您在代码中使用辅助方法
<强> index.html.slim
-@tutos.each do |tuto|
.box.panel-default
= link_to image_tag(image_by_category(tuto.category.try(:name))), tuto_path(tuto)
<强> application_helper.rb
def image_by_category(name)
images = {
"Ruby" => "select/ruby.png",
"Rails 4" => "select/rails4.png",
"Rails 5" => "select/rails5.png",
"Heroku" => "select/heroku.png",
"AWS-Amazon" => "select/aws.png"
}
images[name]
end
答案 1 :(得分：1)
Tuto.all.includes（：user＆amp;＆amp;：category）
应该是
Tuto.all.includes(:user, :category)
答案 2 :(得分：1)
在这个@tutos循环中，你的一个类别不存在或者为nil，因此nil不存在name方法并且抛出错误，为此，你可以用两种方式解决它。
1）检查循环开始时是否存在类别（如果存在），然后仅进入，
-@tutos.each do |tuto|
.box.panel-default
-if tuto.category.present?
-if tuto.category.name == "Ruby"
= link_to(image_tag("select/ruby.png"), tuto_path(tuto))
-elsif tuto.category.name == "Rails 4"
= link_to(image_tag("select/rails4.png"), tuto_path(tuto))
-elsif tuto.category.name == "Rails 5"
= link_to(image_tag("select/rails5.png"), tuto_path(tuto))
-elsif tuto.category.name == "Heroku"
= link_to(image_tag("select/heroku.png"), tuto_path(tuto))
-elsif tuto.category.name == "AWS-Amazon"
= link_to(image_tag("select/aws.png"), tuto_path(tuto))
2）使用try继续执行而不检查错误
-@tutos.each do |tuto|
.box.panel-default
-if tuto.try(:category).try(:name) == "Ruby"
= link_to(image_tag("select/ruby.png"), tuto_path(tuto))
-elsif tuto.try(:category).try(:name) == "Rails 4"
= link_to(image_tag("select/rails4.png"), tuto_path(tuto))
-elsif tuto.try(:category).try(:name) == "Rails 5"
= link_to(image_tag("select/rails5.png"), tuto_path(tuto))
-elsif tuto.try(:category).try(:name) == "Heroku"
= link_to(image_tag("select/heroku.png"), tuto_path(tuto))
-elsif tuto.try(:category).try(:name) == "AWS-Amazon"
= link_to(image_tag("select/aws.png"), tuto_path(tuto))