From: Morton Goldberg <m_goldberg@...>
Date: 2007-10-08T11:18:23+09:00
Subject: Re: Ruby TKentry

On Oct 7, 2007, at 3:41 PM, Erik Boling wrote:

> So, i have been programming for about a month or so and i decided  
> to try
> out a GUI for some of my programs. I just started using ruby tk. I  
> found
> some tutroials, but there not very detailed.
> I have been fooling around with it a bit, but i cant get the TKentry
> class to work.Supposedly according to the tutorials, it is used for
> getting input, but i dont know how to store the data.
> heres an example:
> puts 'how old are you?'
> age = gets.chomp.
>
> for TK its:
> entry = TkEntry.new(root).pack # equivalent to gets *I'm guessing*
>
> but im not sure how to store the input..?
> also i have noticed things like sleep 3 don't work with TK?
>
> If any one knows any good tutorials or just has the answer to my
> questions that would be much appreciated
>
> ps, sorry if im using the wrong *wordage* for things, Im quite new to
> programming.

A TkEntry widget will store the input (the text the user enters) in  
it's value attribute. Given

    entry = TkEntry.new(root).pack

you can get it with

    current_value = entry.value

and set it with

    entry.value = new_value

Here is an example based on one in the Pick Axe book. The original  
used a TkVariable to store the text, but I have modified it to work  
the way I have described above.

<code>
#! /usr/bin/ruby

# Sample code from Programing Ruby, page 259
# Modified: Morton Goldberg
# Date: May 16, 2006

require 'tk'

class PigBox
    def pig(word)
       leading_cap = word =~ /^[A-Z]/
       word.downcase!
       res = case word
             when /^[aeiouy]/ then word + "way"
             when /^([^aeiouy]+)(.*)/ then $2 + $1 + "ay"
             else word
             end
       leading_cap ? res.capitalize : res
    end

    # This reads the TkEntry's text, modifies it, and writes it back
    # out to the widget.
    def show_pig
       @entry.value = @entry.value.split.collect{|w| pig(w)}.join(" ")
    end

    # Commented-out code allowed me to determine attractive geometry
    # values for root window.
    def pig_exit
       # puts Tk.root.winfo_geometry
       exit
    end

    def initialize
       # (me = self) is trick to make PigBox object visible within  
blocks
       # supplied to widget constructors.
       me = self
       xy_pad = {'padx'=>15, 'pady'=>10}
       # Want light blue background for all elements except buttons.
       # Color names and rgb values are given in 'colors (n)' man page.
       bg = {'background'=>'light blue'}
       # This is needed to make butons blend into background.
       hbg = {'highlightbackground'=>'light blue'}
       root = TkRoot.new(bg) {
          title "Pig Latin"
          geometry '450x100+900+50'
          resizable false, false
       }
       # Lay out label and entry box horizontally in upper frame.
       top = TkFrame.new(root, bg)
       h = xy_pad.dup
       h['side'] = 'left'
       TkLabel.new(top, bg) {
          text 'Enter Text:'
          pack(h)
       }
       h['side'] = 'right'
       h['fill'] = 'x'
       h['expand'] = true
       @entry = TkEntry.new(top) {
          font "System 14"
          pack(h)
       }
       top.pack('fill'=>'both', 'side'=>'top')
       # Lay out Pig It and Exit buttons horizontally on right side of
       # lower frame.
       bottom = TkFrame.new(root, bg)
       h = xy_pad.dup
       h['side'] = 'right'
       exit_btn = TkButton.new(bottom, hbg) {
          text 'Exit'
          command { me.pig_exit }
          pack(h)
       }
       pig_btn = TkButton.new(bottom, hbg) {
          text 'Pig It'
          command { me.show_pig }
          pack(h)
       }
       bottom.pack('fill'=>'both', 'side'=>'bottom')
    end
end

PigBox.new
Tk.mainloop
</code>

You might wish to check out the original pig latin example at

    http://www.ruby-doc.org/docs/ProgrammingRuby/html/ext_tk.html

Regards, Morton