Phoenix dynamically generate radio buttons

Phoenix Forum Questions / Help
, ,
1

I’m trying to generate some radio buttons dynamically. It’s easy enough when I have two options I can use = radio_button(f, :field_name, “false”) and radio_button(f, :field_name, “true”) . But what if I want to generate several options from a map? Are there any markup generators I can use to keep my code dry? Like: TemplateHelper.generate_radio(data)?

2

What about using a list comprehension?

https://hexdocs.pm/phoenix/templates.html#examples

scan down to Displaying Lists

2 Likes
3

Thank you, that link was super helpful! I’ve got something working using the following:

<div class="form-control">
  <%= for l <- parse_function @data do %>
    <div class="pretty p-default p-curve">
        <%= radio_button(f, :field_name, elem(l, 1)) %>
        <div class="state">
            <label><%= elem(l, 0)%></label>
        </div>
    </div>
  <% end %>
</div>

Is there an approach where I can encapsulate that in another function, so I could just call something like radio_group(@data, :field_name)?

4

You can use the render function in a view. You can create a shared view (name it whatever, SharedView, FormHelpersView, etc) and move the rendering there.

# in the template, form.html.eex
render MyApp.SharedView, "radio_group.html", form: f, data: @data, field: :field %>

2 options for the shared view template. Return the html from the view’s render function or create a template.

defmodule MyAppWeb.SharedView do
  use MyAppWeb, :view
  
  def parse_function(data) do 
    ...
  end

  # return html from view function
  def render("radio_group.html", %{form: f, data: data, field: field) do
    ~E(
         <div class="form-control">
           <%= for l <- parse_function data do %>
           <div class="pretty p-default p-curve">
             <%= radio_button(f, field, elem(l, 1)) %>
              <div class="state">
                <label><%= elem(l, 0)%></label>
             </div>
           </div>
          <% end %>
      </div>
    )
  end

end

If you do not want to return the html in the view function you can create a template for it like any other view template/shared/radio_group.html.eex.

Reference:
sigil_E/2
https://hexdocs.pm/phoenix_html/Phoenix.HTML.html#sigil_E/2
Phoenix View
https://hexdocs.pm/phoenix/1.4.0-rc.1/views.html#rendering-templates
The examples shown for rendering custom scripts in the phoenix docs for render_existing/3 really helped me.
https://hexdocs.pm/phoenix/1.4.0-rc.1/Phoenix.View.html#render_existing/3

2 Likes
5

Mike thank you for the response, and the links to read more information. I really appreciate how this community values helping and learning! In that spirit, I just wanted to add one piece I learned is that the close parenthesis “)” symbol needs to be escaped in sigil E. So I had to rewrite

<%= radio_button(f, field, elem(l, 1)) %>

as

<%= radio_button(f, field, elem(l, 1\)\) %>

1 Like
6

That’s why I like using """ or so for template sigils. :slight_smile:

7

Any closing delimiter matching the opening delimiter has to be escaped, that is by design of the sigils.,

As a rule of thumb, when you have multiline content just use """ or '''. They will rarely occur in your literal. If your snippet were a onliner, you could also use ', [/], or {/} as delimiter, which seem to not clash on a first glance.

1 Like