From: Hidetoshi NAGAI <nagai@...>
Date: 2004-04-26T10:54:21+09:00
Subject: Re: tk: how to dynamically remove / add widgets?

Hi, 

From: "Its Me" <itsme213@hotmail.com>
Subject: Re: tk: how to dynamically remove / add widgets?
Date: Mon, 26 Apr 2004 00:09:06 +0900
Message-ID: <gsQic.23285$hR1.12603@fe2.texas.rr.com>
> This seems to be about binding and re-binding the callbacks on a widget.
> What I want to do is actually remove widgets and add new widget to some
> containing frame.

I intend to show that a callback for a widget can control another
widget. In other words, you can pack/unpack some widgets in a 
callback procedure. If you hate the frame size is changed when packing
some widgets in the frame, you must set TkPack.propagate to false. 
Please see the following sample script, and compare the difference
of propagate mode (true/false).
-----------------------------------------------------------
#!/usr/bin/env ruby
require 'tk'

TkLabel.new(:text=>"Please click the bottom frame").pack

f = TkFrame.new(:width=>400, :height=>100, :background=>'yellow', 
		:relief=>'ridge', :borderwidth=>5).pack

TkPack.propagate(f, false)  # <== important!!

list = (1..3).collect{|n|
  TkButton.new(f, :text=>"button-#{'X'*n}"){
    command proc{
      puts "button-#{'X'*n}"
      self.unpack
    }
  }
}

f.bind('1', proc{
	 w = list.shift
	 w.unpack
	 list.push(w)
	 list[0].pack(:anchor=>:center)
       })

Tk.mainloop
-----------------------------------------------------------
-- 
                                  Hidetoshi NAGAI (nagai@ai.kyutech.ac.jp)