test_completion.rb

require 'rubygems'
require 'libglade2'

class GtkDefinition

  attr_reader :definition
  
  def initialize
     @definition = '<?xml version="1.0"?>
                    <interface>
                      <requires lib="gtk+" version="2.16"/>
                      <!-- interface-naming-policy project-wide -->
                      <object class="GtkWindow" id="window">
                      <property name="visible">True</property>
                        <child>
                          <object class="GtkEntry" id="entry">
                            <property name="visible">True</property>
                            <property name="can_focus">True</property>
                            <property name="invisible_char">&#x25CF;</property>
                          </object>
                        </child>
                      </object>
                      <object class="GtkEntryCompletion" id="entrycompletion">
                        <property name="text_column">1</property>
                        <signal name="match_selected" handler="on_entrycompletion_match_selected"/>
                      </object>
                    </interface>' 
  end
end

class Item

  attr_reader :value
  
  def initialize(value)
    @value = "value" + value.to_s
  end

end

class TestCompletion

  def get_items
    return (0..10).inject([]) { |items, number| items << Item.new(number) }
  end

  def initialize
    builder = Gtk::Builder.new
    builder << GtkDefinition.new.definition
    
    builder.connect_signals do |signal|
      method(signal)
    end

    entry            = builder.get_object('entry')
    completion       = builder.get_object('entrycompletion')
    completion.set_match_func do |comp, key, iter|
      true
    end
    completion.text_column = 1
    entry.completion = completion

    list_store = Gtk::ListStore.new(Object, String)
    get_items.each do |item|
      iterator    = list_store.append
      iterator[0] = item
      iterator[1] = item.value.to_s
    end
    completion.model = list_store
  end

   def on_entrycompletion_match_selected(widget, model, iter)
     p iter[0]
   end
   
end

TestCompletion.new
Gtk.main