Presenter未定義的局部變量或方法`params'

Question

我有一個索引視圖變得稍微笨重，所以我將所有的數據庫查詢都移到了演示者的嘗試和清理之中。

但是，使用PARAMS [：東西]有任何查詢，使演示錯誤出具有：

undefined local variable or method params for QuestionPresenter:0x007fd6d569c158

我曾嘗試PARAMS遷入ApplicationController的輔助方法和模型，但沒有成功。

如何讓這些參數可用於演示者？或者演講者不是想要處理這些參數？

老question_controller.rb

def index  
    if params[:tag] 
     @questions = @question.tagged_with(params[:tag]).paginate(page: params[:page], per_page: 20) 
    elsif params[:search] 
     @questions = @question.paginate(page: params[:page], per_page: 20).search(params[:search]) 
    else 
     @newest = @questions.newest.paginate(page: params[:page], per_page: 2) 
     @unanswered = @question.unanswered.paginate(page: params[:page], per_page: 2).search(params[:search]) 
     @votes = @question.by_votes.paginate(page: params[:page], per_page: 2).search(params[:search]) 
    end 
end 

QuestionsController.rb（新的索引操作）

def index 
    @presenter = QuestionPresenter.new 
end 

question_presenter.rb

class QuestionPresenter 
    def initialize 
    @questions = Question 
    @tags = Tag 
    end 

    def questions 
    @questions.paginate(page: params[:page], per_page: 20).search(params[:search]) 
    end 

    def tags 
    @tags.joins(:taggings).select('tags.*, count(tag_id) as "tag_count"').group(:tag_id).order(' tag_count desc') 
    end 

    def tagged_questions 
    @questions.tagged_with(params[:tag]) 
    end 

    def newest 
    @questions.newest.paginate(page: params[:page], per_page: 20) 
    end 

    def unanswered 
    @questions.unanswered.paginate(page: params[:page], per_page: 20) 
    end 

    def votes 
    @questions.by_votes.paginate(page: params[:page], per_page: 20) 
    end 
end 

index.html.erb

<%= render partial: "questions/tag_cloud", locals: {tags: @presenter.tags} %> 

<% if params[:search] %> 
    <%= render partial: "questions/questions", locals: {questions: @presenter.questions} %> 
<% elsif params[:tag] %> 
    <%= render partial: "questions/questions", locals: {questions: @presenter.tagged_questions}%> 
<% else %> 
    <%= render partial: "questions/tabbed_index", locals: {questions: @presenter.newest, unanswered: @presenter.unanswered, votes: @presenter.votes} %> 
<% end %> 

Answer 1

你在params哈希表通過從控制器到您的QuestionPresenter：

QuestionsController.rb（新的索引操作）

def index 
    @presenter = QuestionPresenter.new(params) 
end 

question_presenter.rb

class QuestionPresenter 
    def initialize(params = {}) 
    @questions = Question 
    @tags = Tag 
    @params = params 
    end 

    def params 
    @params 
    end 

    ... 

end 

Answer 2

該變量只能從Controller或View訪問。

您必須將它傳遞給QuestionPresenter才能訪問它。 例如，你可以通過是對QuestionPresenter#new方法，讓你在initialize方法得到它，你可以將它保存到一個實例變量@params和@params到處替換params的QuestionPresenter類。