无法通过 image_tag 在 rails 中显示图像

Question

I am trying to make a very simple rails program to show a picture and here is my show.html.erb file

<div class="row">  <div class="col m12">
<div class="card blue-grey darken-1">
  <div class="card-content white-text">
    <div class="row">
      <div class="col m4 center">
      <%= image_tag "courses/#{@course.image}" %>    
      </div>
      <div class="col m8">
      <span class="card-title"><%= @course.title %></span> 
      <p><%= @course.description %></p>         
    </div>
   </div>
  </div> </div></div></div>

What I want is, for example, in the folder courses, there are 4 images 1 2 3 4, when I connect to the http://localhost:3000/courses/2 , it will show the picture 2, but it gave me this problem The asset "courses/image" is not present in the asset pipeline.

I am very confusing am tried to fixed it but could not. I am a newbie and still stydying, could you please give me some ideas? Thank you very much.

Answer 1

What you need in different ways is:

  <%= image_tag "courses/1.png" %>
  <%= image_tag "courses/2.png" %>
  <%= image_tag "courses/3.png" %>
  <%= image_tag "courses/4.png" %>

So, you should do one of these:

• Try saving full path_name (after images directory) for every course ie

  @course.image = "courses/n.png" # where n is any name for the image for that course
  # then:
  <%= image_tag @course.image %>

• Just save the number in @course.image but use the path like you are already doing:

  @course.image = n
  <%= image_tag "course/#{@course.image}.png" %>

First one is the standard way of course. Your @course.image should have the complete path in it. image_tag is expecting a string which will be a path and your @course.image should be having it, instead of you writing a part of it yourself. Remember, that file extension is a "part" of the path so you should not ignore it.

Hint: You can add size of the image too in this tag. It is very helpful:

  <%= image_tag @course.image, size: "100x100" %>