Question

我正在尝试创建下一个按钮，每个页面只显示一条记录。我知道我们可以使用分页但我只想拥有下一个按钮。所以，我阅读了以下帖子并实现了它：我的问题控制器：

class QuestionsController < ApplicationController
  before_action :set_page, only: [:view]
  QUESTIONS_PER_PAGE = 1
  def view
    questions=[]
    @evaluation = Evaluation.pluck(:content).last
    @evaluation.each do |question|
      questions << question
    end
    @questions=Question.where(:content => questions).limit(QUESTIONS_PER_PAGE).offset(@page*QUESTIONS_PER_PAGE)
    #@questions=Question.where(:content => questions).paginate(page: params[:page],per_page: 1)
  end
  private
    def set_page
       @page = params[:page] || 0
    end

我的view.html.erb ，它给出了错误：没有将Integer隐式转换为String

<h1>Self-Evaluation Exam</h1>

<table id="questions">
    <thead>
        <tr>
            <th>Content &nbsp; &nbsp; &nbsp;</th>
        </tr>
    </thead>
    <tbody>
        <% @questions.each do |question| %>
          <tr>
            <td><%= question.content %></td>
            <td><%= check_box_tag question.c1 %></td>
            <td><%= question.c1%></td>
            <td><%= check_box_tag question.c2 %></td>
            <td><%= question.c2%></td>
            <td><%= check_box_tag question.c3 %></td>
            <td><%= question.c3%></td>
            <td><%= check_box_tag question.c4 %></td>
            <td><%= question.c4%></td>
            <td><%= check_box_tag question.c5 %></td>
            <td><%= question.c5%></td>
          </tr>
        <% end %>
    </tbody>
</table>
<div id = "nav">
    <%= button_to 'Next',questions_path(page: @page + 1) %># this line gives error: no implicit conversion of Integer into String
</div>
<li><%= link_to 'Personal Evaluation',instructions_student_path %></li>

Paginate without a gem Next, Previous, buttons for Name.order(:id).limit(10).offset(0) 它显示了第一页，但是当我点击按钮时，我得到了错误 PS：下一个按钮应该在最后一条记录上改为提交谢谢

Answer 1

错误告诉您网址构建器失败，因为它尝试将整数转换为字符串。此外，递增值通常为+ =。

我打赌params [：page]返回的是字符串而不是整数。如果你@page.to_i += 1会怎么样？沿着这些方向的东西至少会让你超越这个初始错误。

Answer 2

非常简单，请尝试以下

QUESTIONS_PER_PAGE = 1
@questions = Question.where(content: questions).offset(QUESTIONS_PER_PAGE * @page).limit(QUESTIONS_PER_PAGE)

private
def set_page
   @page = (params[:page] || 0).to_i
end

使用view.html.erb和next >>

更改为<< previous

<div id="nav">
    <nav>
        <ul class="pager">
            <li class="previous <%= @page == 0 ? 'disabled' : '' %>">
                <%= link_to_if page > 0, "&larr; Previous".html_safe, questions_path(page: @page - 1) %>
            </li>
            <li class="next">
                <%= link_to "Next &rarr;".html_safe, questions_path(page: @page + 1) %>
            </li>
        </ul>
    </nav>
</div>

所以你的controller看起来像这样

class QuestionsController < ApplicationController
    before_action :set_page, only: [:view]
    QUESTIONS_PER_PAGE = 1
    def view
        questions=[]
        @evaluation = Evaluation.pluck(:content).last
        @evaluation.each do |question|
          questions << question
        end
        @questions = Question.where(content: questions).offset(QUESTIONS_PER_PAGE * @page).limit(QUESTIONS_PER_PAGE)
    end

    private
    def set_page
       @page = (params[:page] || 0).to_i
    end
end

如果您只需要查看下一个按钮，则只能使用

<%= link_to "Next &rarr;".html_safe, questions_path(page: @page + 1) %>

有条件

<% if @page == @questions.count %>
    <button>Finished</button>
<% else %>
    <%= link_to "Next &rarr;".html_safe, questions_path(page: @page + 1) %>
<% end %>

仅使用下一个按钮进行分页

2 个答案: