Simple Navigation of Array

rubyonrails-talk
1

Goal: Browse a specific set of database records (the array @features) as a list. Select an item from list (item[3]) to view. On item page (i.e. ./show/3 ) navigate to previous / next item page using generated links.

This solution is working for part of the goal:

    ItemController         def list             @features = Item.find(:all, :conditions => "featured = 1")         end

    list.rhtml   <% for feature in @features -%>     <%= link_to(feature.title, {:action => 'show', :id => feature.id} ) - %>   <% end-%>

Then I get stuck:

    ItemController         def show             ? ? ? ?         end

    show.rhtml         <a href="./items/show/<%= ? ? ? ? %>">Previous</a>         <a href="./items/show/<%= ? ? ? ? %>">Next</a>

Walkthrough:   browse to: ./items/list/ (displays the array @ features = [3, 5, 12, 19] )   click the text link "item_5_title" ( @features[1] )   arrive at: ./items/show/5   click the text link "next"   *should* arrive at: ./items/show/12 ( @features[3] )

How do I tell the previous / next link where to go?

2

I'm pretty new at this too, but it sounds like you just want to paginate thru a list with a limit of one item per page. Couldn't you just use the next/previous links that get generated for the list page and put them on your show page? Can you paginate @features instead of the default paginate :items? I think it uses the id field by default anyways, so it should be able to generate it that way. Am I making any sense?

3

Thanks for the suggestions Rick. I am definitely new at this.

This is what I am trying as per your suggestion.

    ItemController         def show             # Load item by id in order to populate page.             @item = Item.find(params['id'])

            # Create array of all items with "featured = 1"             @features = Item.find(:all, :conditions => "featured = 1")             @feature_pages, @features = paginate(:features, :per_page => 1)         end

    show.rhtml         <%= link_to('Previous', { :page => @feature_pages.current.previous }) -%>         <%= link_to('Next', { :page => @feature_pages.current.next }) - %>

When I try to load a page ( ./items/show/3 ) in the browser I am getting an error.

    NameError in PortfolioController#try         uninitialized constant Feature

I tired initializing feature as an array ( @features = ) n my controller to no avail.

Where am I messing this up?

4

This is what I'm doing in a app I'm working on (I changed my model name to "feature" to match yours). I have a "number" field associated with each record, and use that for the order. Change to suit.

In the controller's Show method:

    @feature = Feature.find(params[:id])     @previous = Feature.find(:first, :order => "number desc", :conditions => ["number < ?", @feature.number])     @next = Feature.find(:first, :order => "number", :conditions => ["number > ?", @feature.number])

In the show.rhtml file:

    <p><%= link_to('Previous', feature_path(@previous)) unless @previous.blank? %> | <%= link_to('Next', feature_path(@next)) unless @next.blank? %></p>

HTH, jt

5

John,

I think (and may be wrong), but the situation I am working from is slightly different from where you started.

My model is not "Feature". My model is "Item" and has an associated field named "featured" that accepts 1 or 0 (yes or no). I am guessing your suggested "number" field accepts any number and acts as a mechanism to sequence the featured items, basically it is an additional unique identifier (although not the primary key). I am instead using feature as a concept referring to a subset of Items which have the attribute "featured = 1". I only mention this, because I cannot simple "change to suit" since our setup is different.

I am new to ruby, so please excuse my misinterpretation if your code does in fact fit my circumstance.

If you would explain a little further how @previous and @next are working in the controller it might help me see the direction your guiding me towards. Also, in the view code you provided, what does "feature_path" call? Is it calling all the code you provided in the controller show method? I am missing what "feature_path" calls.

I appreciate your help. Thank you.