Edit a submit btn for nested form - ruby-on-rails

Question

I would like to customize the submit file btn. To do that, I'm using a pure css trick. But the problem is that this is not working as well than before the editing. I'm using cocoon to add images to my instance as a nested file.
I'm changing this (works perfectly) :
<div class="nested-fields col m4 s6">
<div class="flat_photo_box">
<%= f.file_field :image %>
</div>
</div>
Into this (partially works):
<div class="nested-fields col m4 s6">
<div class="image-upload">
<label for="file-input<%=f.object.id%>">
<span class="fa fa-download trash_nested_form"></span>
</label>
<%= f.file_field :image, id:"file-input#{f.object.id}" %>
</div>
</div>
With this css trick :
.image-upload > input
{
display: none;
}
.image-upload > label{
cursor:pointer;
}
ERROR = I can create as much nested form than I want, but paperclip only save the last image that I upload into the first nested element. Do you have an idea of where the mistake might come from

Answer 1

You assign an id to the file_field, a html-id is supposed to be unique. While the page will render correctly, upon form submit only one will be submitted to the server. Instead write your field like this:
<%= f.file_field :image, class:"file-input#{f.object.id}" %>
Why do you want to assign a specific id?