Forum: Ruby-Gnome 2 reference to an object

I am trying to understand building an app using Glade and Ruby.  I have 
a
test app that has a top-level window with a fixed container.  The 
container
has three buttons on it.  I would like to know how to reference those
buttons in Ruby code to do simple things like disable or enable them 
using
the sensitive attribute.

During the app startup I am keeping a reference to the window object via 
a
builder using get_object

window = builder.get_object("my_window")

# the following code works and disables all of the buttons
window.children.first.children.each do |obj|
  obj.sensitive = false
end

However, I was looking for a way to reference the button object 
directly.

window.fixed_container.button_quit.sensitive = false

or at least something along those lines.  Do I have to use the builder
instance to get a reference to one of the buttons?  I'm looking for the
preferred way to accomplish this task.

Thanks!!

Hi,

There are many open-source Ruby Gtk+ apps for you to browse the source 
code.

http://launchpad.net/studly   (flashcard trainer)
http://launchpad.net/screenruler   (on-screen ruler)
http://launchpad.net/luz    (motion graphics editor)

> However, I was looking for a way to reference the button object directly.
>
> window.fixed_container.button_quit.sensitive = false

You can achieve this by mixing Ruby's attr_accessor feature with the
array of widgets symbols in any of those above apps.  See
glade_window.rb in Studly for example.

Though I recommend you don't do this, and instead do
window.set_some_state and let that method configure the window.

-Ian

Hi:

Ian's code is a great resource.  He's helped me learn many things in
ruby.


I'll give you a few basics:

>  window = builder.get_object("my_window")

This can be abbreviated to this:

window = builder["my_window"]

and to set the title, for example, you could just use:

builder["my_window"].title = "Title appears at top of window"

or

builder["button1"].sensitive = false

Normally, you'd want "builder" to be an instance variable @builder
instead, so you can use it everywhere in your class.  I've written an
IDE for ruby that uses that exact variable name, @builder to do exactly
what you're trying to do.  You can see simple examples at
visualruby.net.

Good luck,
Eric

Thanks guys!!  I picked up some very good ideas...

On Mon, Mar 5, 2012 at 5:01 PM, Eric C.

hi W.W. -

> ... I was looking for a way to reference the button object
> directly.
>
> window.fixed_container.button_quit.sensitive = false

  i don't use glade, and the builder suggestions above are great - but
couldn't you just use an instance variable to reference the buttons?  i
often do something like this:

require 'gtk2'

class Nothing
  def initialize
    win = Gtk::Window.new
    win.signal_connect("destroy"){Gtk.main_quit}
      box = Gtk::HBox.new(true, 2)
        button1 = Gtk::Button.new("click me and see")
        button1.signal_connect("clicked"){button1_click_event}
        @button2 = Gtk::Button.new("I'm just a pawn in this game")
        @button2.signal_connect("clicked"){p "I'm button2, and I'm
feeling sensitive"}
      box.pack_start(button1, true, true, 2)
      box.pack_start(@button2, true, true, 2)
    win.add(box)
    win.show_all
    @switch_button2 = false
  end

  def button1_click_event
    p "I'm the master of this game!"
    @button2.sensitive = @switch_button2
    @switch_button2 = !@switch_button2
  end
end

n = Nothing.new
Gtk.main


  - j

Hi Jake:

I'd encourage you to take a look at a program that I just made
available,
visualruby.  It can really streamline your code.  For example all the
code that you wrote above could be reduced to this:

class Nothing

  def initialize
    @button1 = "click me and see"
    @button2 = "I'm just a pawn in this game"
    load_glade(__FILE__)
    set_glade_variables
    @switch_button2 = false
    show_window()
  end

  def button2__clicked
    p "I'm button2, and I'm feeling sensitive"
  end

  def button1__clicked
    p "I'm the master of this game!"
    @builder["button2"].sensitive = !@switch_button2
    @switch_button2 = !@switch_button2
  end

end

And if you set the values of button1 and button2 in glade, and fixed
button1_clicked:

class Nothing

  include GLadeGUI

  def initialize
    load_glade(__FILE__)
    show_window()
  end

  def button2__clicked
    p "I'm button2, and I'm feeling sensitive"
  end

  def button1__clicked
    p "I'm the master of this game!"
    @builder["button2"].sensitive = !@builder["button2"].sensitive
  end

end

I know that your code works, but using visualruby and glade will
unclutter it.

take a look at visualruby.net

Best,
Eric

hi Eric,
>
> take a look at visualruby.net
>

  i will, looks interesting - definitely less clutter in the code...

  - j