Auto complete field on simple form with params - ruby-on-rails

Question

I have two models 'activity_templates' and 'activity'. I want to create a link on the activity_template index to create a new activity. I want to send activity_template params to the active form. I want to autocomplete the activity_template field on new activity form.
I can't figure out how to pass the params on the index page.
I think its a problem with the link.
Link:
<div class="box">
<div class="box-header">
<h3 class="box-title">Activities</h3>
</div>
<div class="box-body table-responsive no-padding">
<table class="table table-bordered">
<tbody>
<% #activity_templates.each do |activity_template| %>
<tr>
<td><%= activity_template.name %></td>
</tr>
<% end %>
</tbody>
</table>
<div class="text-right">
<%= will_paginate #activity_templates %>
</div>
</div>
</div>
URL:
http://localhost:3000/app/activities/new
Form:
<%= simple_form_for([:app, #activity]) do |f| %>
<%= f.error_notification %>
<div class="form-inputs">
<div class="row">
<div class="col-md-6">
<%= f.association :resident, label_method: :full_name, prompt: "Choose a resident", collection: Resident.order(:first_name), selected: #resident.id %>
</div>
<div class="col-md-6">
<%= f.association :activity_template, collection: ActivityTemplate.order(:name).pluck(:name, :id), prompt: "Choose an activity template", selected: #activity_template.id %>
</div>
<div class="col-md-6">
<%= f.input :published_status, collection: ['Draft', 'Final'], default: 'Draft' %>
</div>
<div class="col-md-6">
<div class="form-group">
<label>Author</label>
<input class="form-control" type="text" placeholder="<%= #current_user.full_name %>" readonly value="<%= #activity.author.try(:full_name) %>">
</div>
</div>
</div>
<%= f.input :data %>
</div>
<div class="form-actions">
<%= f.button :submit %>
</div>
<% end %>
Activity controller:
def new
#activity = current_business.activities.new
if params[:resident_id].present?
#resident = Resident.find(params[:resident_id])
end
if params[:activity_template_id].present?
#activity_template = ActivityTemplate.find(params[:activity_template_id])
end
end

Answer 1

I want to send activity_template params to the active form.
You should change #activity_template to activity_template in the link as you are iterating #activity_templates as activity_template.
<td><%= activity_template.name %></td>
Now you should see activity_template_id value in the url
http://localhost:3000/app/activities/new?activity_template_id=value
As you already capturing the params[activity_template_id] in the new, the rest should work now.
Also I recommend using link_to
<%= link_to activity_template.name, new_app_activity_path(activity_template_id: activity_template) %>