I am using the awesome_nested_set gem located here https://github.com/collectiveidea/awesome_nested_set. I would like to make the parent categories optgroup labels but am at a loss on how to make that happen or if it is even possible. Is there an example somewhere of this behavior?
This is certainly not the most efficient way to do this, but it met the requirement of the task.
<select name="category_id" data-placeholder="Select a Category" class="chzn-select">
<option value=""></option>
<% #cats.each do |cat| %>
<optgroup label="<%= cat.name %>">
<% cat.children.each do |child| %>
<option value="<%= child.id %>"><%= child.name %></option>
<% end %>
</optgroup>
<% end %>
</select>
A little late, but I had the same question and solved it by using a helper method according to https://github.com/collectiveidea/awesome_nested_set/blob/master/lib/awesome_nested_set/helper.rb
module ApplicationHelper
def grouped_nested_set_options(class_or_item, mover = nil)
if class_or_item.is_a? Array
items = class_or_item.reject { |e| !e.root? }
else
class_or_item = class_or_item.roots if class_or_item.respond_to?(:scope)
items = Array(class_or_item)
end
result = []
group = []
items.each do |root|
root.class.associate_parents(root.self_and_descendants).map do |i|
if i.level == 0
group = []
group.push yield(i)
group.push []
result.push group
else
if mover.nil? || mover.new_record? || mover.move_possible?(i)
group[1].push [yield(i), i.primary_id]
end
end
end.compact
end
result
end
end
That way you can just use grouped_nested_set_options instead of nested_set_options and you can still use rails' form helpers for generating the html.
Related
I'm new to ruby on rails and I'm facing a problem rendering nested questions.
What I want to achieve is rendering the question and check if it have children question then render the children questions as well.
there is no limit on the nesting levels, so I have to use recursion method to achieve this and this is what I came up with.
# view file code
<% #questions.each do |q| %>
<%= render partial: "shared/question_block", locals: {q: q} %>
<% if have_children_questions?(q.id) == 'true' %>
<%= print_children_questions( get_children_ids(q.id) ) %>
<% end %>
<% end %>
and here is the helper functions I created
def have_children_questions?(id)
children = Question.get_children(id)
if !children.empty?
'true'
else
'false'
end
end
def get_children_ids(id)
ids = Question.where(parent: id).pluck(:id)
end
def print_children_questions(ids)
ids.each do |id|
q = Question.find(id)
render partial: "shared/question_block", locals: {q: q}
if have_children_questions?(id)
print_children_questions( get_children_ids(id) )
end
end
end
print_children_questions method returning the ids instead of the partial view, what I'm doing wrong?
is there is a better solution
Thanks in advance
I'd like to group a collection alphabetically by title:
#projects = Project.find_all_by_user_id(current_user.id)
The view should contain a list of projects grouped by title, e.g.:
A
Andre's Project
Ananas
C
Chemnitz
Cleopatra
F
Find a new office
S
Super secret stuff
But I got no clue how to do this in rails. Does rails provide a functionality to do this or do I need to write my own loop looking for the titles etc.?
Thank you!
Not Rails but Ruby does the trick. In your view:
<% #projects.group_by{ |project| project.name[0].downcase }.each do |letter, projects| %>
<div id="letter-<%= letter %>" class="letter-group">
<h2><%= letter.upcase %><h2>
<% projects.each do |project| %>
<p><%= link_to project.name, project %></p>
<% end %>
</div>
<% end %>
group_by (ruby-doc) returns a hash you can easily loop through with letters as keys and arrays of corresponding projects as values. Be sure to already get your records sorted by project's name: (in your controller)
#projects = Project.order("name ASC").find_all_by_user_id(current_user.id)
I have a list of organisations, grouped and displayed by their name, in alphabetical order. I want to display these across 4 columns for each letter, i.e.:
A
A... A... A... A...
A... A... A... A...
...
Z
Z... Z...
I have used the following code:
<% #organisations.keys.sort.each do |starting_letter| %>
<div class="page-chunk default">
<h6><%= starting_letter %></h6>
<% #organisations[starting_letter].each do |organisations| %>
<% organisations.in_groups_of(4).each do |column| %>
<div class="one_quarter">
<% column.each do |organisation| %>
<%= link_to organisation.name, organisation_path(organisation) %><br />
<% end %>
</div>
<% end %>
<% end %>
</div>
<% end %>
And in the controller:
#organisations = Organisation.all.group_by{ |org| org.name[0] }
But get undefined methodin_groups_of' for #for my troubles. If I change the code to#organisations[starting_letter].in_groups_of(4).each do |organisations|then I get aNilClass` error.
What have I done wrong and how should I fix it?
Try organisations.in_groups_of(4, false)
Without the false, it will fill in any empty spots in the last group with nils, which means it will try to call name on nil.
I am using a helper method from ryan bates railscasts on ancestry to display nested messages(code below works perfectly).
def nested_messages(messages)
messages.map do |message, sub_messages|
render(message) + content_tag(:div, nested_messages(sub_messages), :class => "nested_messages")
end.join.html_safe
end
The above bit of code nests the individual divs in a tree like structure. I would like to make this into an unordered list, so what i have done is this:
def nested_messages(messages)
messages.map do |message, sub_messages|
content_tag(:ul, :class => "") do
render(message)
content_tag(:li, :class => "nested_messages") do
nested_messages(sub_messages)
end
end
end.join.html_safe
end
The generated html looks fine, however the list items contain no values. Am i doing something wrong?
UPDATE
I would like the generated html to look like this:
<ul>
<li>Main Message</li> <!-- first message -->
<li>
<b>Message 1</b>
<ul>
<li>Message 1 subchild 1</li>
<li>Message 1 subchild 2</li>
</ul>
</li>
</ul>
UPDATE 2
I have changed it to this and it works, thanks to Dave:
def nested_messages(messages)
messages.map do |message, sub_messages|
#render(message) + content_tag(:div, sub_messages, :class => "nested_messages")
content_tag(:ul, :class => "") do
content_tag(:li, :class => "nested_messages") do
render(message) + nested_messages(sub_messages)
end
end
end.join.html_safe
end
You create a ul tag, then render the message. If you do that, what will your HTML look like?
Things inside a ul should be in a nested li: you just render the message.
You need to put it in an li tag so the unordered list has valid content.
I'm using the awesome_nested_set plugin in my Rails project. I have two models that look like this (simplified):
class Customer < ActiveRecord::Base
has_many :categories
end
class Category < ActiveRecord::Base
belongs_to :customer
# Columns in the categories table: lft, rgt and parent_id
acts_as_nested_set :scope => :customer_id
validates_presence_of :name
# Further validations...
end
The tree in the database is constructed as expected. All the values of parent_id, lft and rgt are correct. The tree has multiple root nodes (which is of course allowed in awesome_nested_set).
Now, I want to render all categories of a given customer in a correctly sorted tree like structure: for example nested <ul> tags. This wouldn't be too difficult but I need it to be efficient (the less sql queries the better).
Update: Figured out that it is possible to calculate the number of children for any given Node in the tree without further SQL queries: number_of_children = (node.rgt - node.lft - 1)/2. This doesn't solve the problem but it may prove to be helpful.
It would be nice if nested sets had better features out of the box wouldn't it.
The trick as you have discovered is to build the tree from a flat set:
start with a set of all node sorted by lft
the first node is a root add it as the root of the tree move to next node
if it is a child of the previous node (lft between prev.lft and prev.rht) add a child to the tree and move forward one node
otherwise move up the tree one level and repeat test
see below:
def tree_from_set(set) #set must be in order
buf = START_TAG(set[0])
stack = []
stack.push set[0]
set[1..-1].each do |node|
if stack.last.lft < node.lft < stack.last.rgt
if node.leaf? #(node.rgt - node.lft == 1)
buf << NODE_TAG(node)
else
buf << START_TAG(node)
stack.push(node)
end
else#
buf << END_TAG
stack.pop
retry
end
end
buf <<END_TAG
end
def START_TAG(node) #for example
"<li><p>#{node.name}</p><ul>"
end
def NODE_TAG(node)
"<li><p>#{node.name}</p></li>"
end
def END_TAG
"</li></ul>"
end
I answered a similar question for php recently (nested set == modified preorder tree traversal model).
The basic concept is to get the nodes already ordered and with a depth indicator by means of one SQL query. From there it's just a question of rendering the output via loop or recursion, so it should be easy to convert this to ruby.
I'm not familiar with the awesome_nested_set plug in, but it might already contain an option to get the depth annotated, ordered result, as it is a pretty standard operation/need when dealing with nested sets.
Since september 2009 awesome nested set includes a special method to do this:
https://github.com/collectiveidea/awesome_nested_set/commit/9fcaaff3d6b351b11c4b40dc1f3e37f33d0a8cbe
This method is much more efficent than calling level because it doesn't require any additional database queries.
Example: Category.each_with_level(Category.root.self_and_descendants) do |o, level|
You have to recursively render a partial that will call itself. Something like this:
# customers/show.html.erb
<p>Name: <%= #customer.name %></p>
<h3>Categories</h3>
<ul>
<%= render :partial => #customer.categories %>
</ul>
# categories/_category.html.erb
<li>
<%= link_to category.name, category %>
<ul>
<%= render :partial => category.children %>
</ul>
</li>
This is Rails 2.3 code. You'll have to call the routes and name the partial explicitely before that.
_tree.html.eb
#set = Category.root.self_and_descendants
<%= render :partial => 'item', :object => #set[0] %>
_item.html.erb
<% #set.shift %>
<li><%= item.name %>
<% unless item.leaf? %>
<ul>
<%= render :partial => 'item', :collection => #set.select{|i| i.parent_id == item.id} %>
</ul>
<% end %>
</li>
You can also sort their:
<%= render :partial => 'item', :collection => #set.select{|i| i.parent_id == item.id}.sort_by(&:name) %>
but in that case you should REMOVE this line:
<% #set.shift %>
Maybe a bit late but I'd like to share my solution for awesome_nested_set based on closure_tree gem nested hash_tree method:
def build_hash_tree(tree_scope)
tree = ActiveSupport::OrderedHash.new
id_to_hash = {}
tree_scope.each do |ea|
h = id_to_hash[ea.id] = ActiveSupport::OrderedHash.new
(id_to_hash[ea.parent_id] || tree)[ea] = h
end
tree
end
This will work with any scope ordered by lft
Than use helper to render it:
def render_hash_tree(tree)
content_tag :ul do
tree.each_pair do |node, children|
content = node.name
content += render_hash_tree(children) if children.any?
concat content_tag(:li, content.html_safe)
end
end
end
I couldn't get to work the accepted answer because of old version of ruby it was written for, I suppose. Here is the solution working for me:
def tree_from_set(set)
buf = ''
depth = -1
set.each do |node|
if node.depth > depth
buf << "<ul><li>#{node.title}"
else
buf << "</li></ul>" * (depth - node.depth)
buf << "</li><li>#{node.title}"
end
depth = node.depth
end
buf << "</li></ul>" * (depth + 1)
buf.html_safe
end
It's simplified by using the optional depth information.
(Advantage of this approach is that there is no need for the input set to be the whole structure to the leaves.)
More complex solution without depths can be found on github wiki of the gem:
https://github.com/collectiveidea/awesome_nested_set/wiki/How-to-generate-nested-unordered-list-tags-with-one-DB-hit