How to do Interactive Page Updates

rubyonrails-talk
1

Hi

I think I'm still in the newbie class of Rails programmers and I may be trying to run before I can walk so this question may have a very simple answer.

I have a page with a small form on it, say Orders. That works fine.

Associated with this form is an additional data set that has a many to one relationship with Orders, say Line Items. This too is fine.

What I want to do is display the orders form and below that allow users to display, add, edit and delete line items. The line items are to be hidden when the form is first displayed with a link that rolls down the line items and another that rolls them back up again. When they roll down there's a link next to each allowing the user to delete the line item.

Most of this I have working!

They can click a Show Line Items lino_to_remote that displays the line items:

<%= link_to_remote 'Show Line Items',   :update => 'line_items',   :url => { :action => 'list', :controller => 'line_items', :id => @order.id },   :complete => visual_effect(:blind_down, 'line_items') %>

My list method looks like:

def list     @lineitems = Lineitem.find(:all, :conditions => "order_id = #{params[:id]}")     render :partial => 'list'   end

My partial looks like:

<p>Click a line item to edit it.</p> <% for lineitem in @lineitems %>   <% @lineitem = lineitem %>

  <p>     <%= in_place_editor_field :lineitem, :name, {}, {} %>     <%= link_to 'Delete', { :action => 'destroy', :id => @lineitem, :controller => 'lineitem' },       :confirm => "Are you sure you want to delete this challenge?",       :method => :post %>   </p> <% end %>

I have a similar link_to_remote that hides them again with a blind_up. I'd like to know if I can do the hide without a call back to the list action, I guess I can use any dummy action that avoids a trip to the database? Anyway that bit works, I can show and hide my line items fine.

What I can't get my head around is how to refresh my list of line items when I add one or delete one? The actual addition and deletion work in that the database is updated; but I then want to refresh my list and I can't figure out just how to do this.

Any pointers gratefully received.

Thanks

David

2

Hi David

You may want to look at Active Scaffold...

3

Thanks for the suggestion.

I took a look at Active Scaffold and it looks very comprehensive. It will do the functionality I want; but there's two reasons I don't want to use it:

1. I have all the controller methods and most of the display sorted; it's just removing elements from the list on delete and adding new ones on create that I need to do.

2. If I rewrite the whole thing using Active Scaffold to handle all the display and control then I'll have learned nothing about the Rails core; which is really what I'm trying to do at the moment. Active Scaffold is just another (sophisticated) scaffold and I want to learn is how to do it in Rails.

What I think I want is an RJS script to do an element remove if a line item has been deleted and an element add if one's been created. What I haven't been able to figure out is the relationship between the RJS files and the rest of the stuff in the view.

Or possible to refresh the list using a replace_html to update the line_items.

Thanks

David

4

I have a similar link_to_remote that hides them again with a blind_up. I'd like to know if I can do the hide without a call back to the list action, I guess I can use any dummy action that avoids a trip to the database? Anyway that bit works, I can show and hide my line items

fine.

sure: link_to_function 'Hide some stuff' do |page|    page.visual_effect :blind_up, 'line_items' end

What I can't get my head around is how to refresh my list of line items when I add one or delete one? The actual addition and deletion work in that the database is updated; but I then want to refresh my list and I can't figure out just how to do this.

2 ways: either you make the rjs for the add/delete actions insert or remove the appropriate item from the DOM, or you make both of those actions render the complete list, and your delete link looks like

link_to_remote 'delete', :url => {:action => 'delete', :id => 3}, :update => 'line items

Fred