From: Morton Goldberg <m_goldberg@...>
Date: 2008-03-11T10:13:30+09:00
Subject: Re: Reading pick from option menu

On Mar 10, 2008, at 12:34 PM, Isaac Toothyxdip wrote:

> WOO got it to work i just completely started over and this is what my
> code is now:
>
> <code>
> require 'tk'
>
> root = Tk.root
> root.title('Hello')
> @entry = TkVariable.new
> @menu_chosen = TkVariable.new
>
> menu_choices = ["Yes", "No"]
> menu_chosen = TkVariable.new
> menu = TkOptionMenubutton.new(root, menu_chosen, *menu_choices)
> menu.pack('pady'=>10)
> @number = menu_chosen
>
> entry = TkEntry.new(root)
> entry.pack('pady'=>10)
> entry.textvariable = @entry
>
> def multiply
>   case @number.value
>     when "Yes"
>       @menu_chosen = 50
>     when "No"
>       @menu_chosen = 30
>   end
>   @entry.numeric *= @menu_chosen
> end
>
> button = TkButton.new(root)
> button.text = "Hello"
> button.pack('pady'=>10)
> button.command { multiply }
>
> #geometry
> min_w, min_h = 200, 200
> root.resizable(flase,false)
> root_x = (root.winfo_screenwidth - min_w) / 2
> root.geometry("#{min_w}x#{min_h}+#{root_x}")
>
> Tk.mainloop
> </code>

Your clearly making progress, but it's clear from this code that you  
don't yet fully understand Ruby variables because you are defining  
unnecessary ones. Compare the following simplified code to what you  
posted.

<code>
require 'tk'

root = Tk.root
root.title('Hello')

menu_choices = ["Yes", "No"]
@menu_chosen = TkVariable.new
menu = TkOptionMenubutton.new(root, @menu_chosen, *menu_choices)
menu.pack('pady'=>10)

entry = TkEntry.new(root)
entry.pack('pady'=>10)
@entry = TkVariable.new
entry.textvariable = @entry

def multiply
    case @menu_chosen.value
    when "Yes"
       num = 50
    when "No"
       num = 30
    end
    @entry.numeric *= num
end

button = TkButton.new(root)
button.text = "Hello"
button.pack('pady'=>10)
button.command { multiply }

min_w, min_h = 200, 150
root.resizable(false, false)
root_x = (root.winfo_screenwidth - min_w) / 2
root.geometry("#{min_w}x#{min_h}+#{root_x}+50")

Tk.mainloop
</code>

You had to invent @number because your multiply method broke the  
binding between @menu_chosen and the TkVariable it was originally  
bound to. But there was no reason to do that. You should have used a  
local variable in multiply as I did.

Also, I am puzzled by use of "Yes" and "No" to represent the numbers  
50 and 30, respectively, in your option menu. It's your program and  
you're entitled to do as you please, but it could be made simpler if  
you just used numbers. As in the following.

<code>
require 'tk'

root = Tk.root
root.title('Hello')

menu_choices = [50, 30]
@menu_chosen = TkVariable.new
menu = TkOptionMenubutton.new(root, @menu_chosen, *menu_choices)
menu.pack('pady'=>10)

entry = TkEntry.new(root)
entry.pack('pady'=>10)
@entry = TkVariable.new
entry.textvariable = @entry

def multiply
    @entry.numeric *= @menu_chosen.numeric
end

button = TkButton.new(root)
button.text = "Hello"
button.pack('pady'=>10)
button.command { multiply }

min_w, min_h = 200, 150
root.resizable(false, false)
root_x = (root.winfo_screenwidth - min_w) / 2
root.geometry("#{min_w}x#{min_h}+#{root_x}+50")

Tk.mainloop
</code>

Regards, Morton