Rubytk - How to use <<ListboxSelect>>

ruby-talk
1

Hello

In the tk reference manual i found an event called ListboxSelect.
I would like to use this to change a buttons state from :normal to :disabled or vice versa.
Say a listbox is empty. Now, edit an entry is not possible so the button should disabled.
After a few seconds the listbox get filled, the edit button should now set to normal state.

Could you post a code snippet to demonstrate this callback functionality

Thanks
Enno

2

Message-ID: <opssml5jeqfoz7gx@x5.linux.net>

In the tk reference manual i found an event called ListboxSelect.

    (snip)

Could you post a code snippet to demonstrate this callback functionality

How about the following?

ยทยทยท

From: "Enrico Schwass" <deckard73@freenet.de>
Subject: Rubytk - How to use <<ListboxSelect>>
Date: Mon, 13 Jun 2005 04:06:24 +0900
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require 'tk'

f = TkFrame.new.pack(:fill=>:x)

entry = TkEntry.new(f).pack(:side=>:left, :expand=>true, :fill=>:x)

b_add = TkButton.new(f, :text=>'ADD', :state=>:normal).pack(:side=>:right)
b_edit = TkButton.new(f, :text=>'EDIT', :state=>:disabled).pack(:side=>:right)

available = b_add
entry.bind('Return', proc{available.invoke})

lbox = TkListbox.new(:selectmode=>:multiple).pack(:fill=>:both, :expand=>true)

old_sel =
lbox.bind('<ListboxSelect>'){
  sel = (lbox.curselection - old_sel)
  if sel.empty?
    entry.value = ''
    b_add[:state] = :normal
    b_edit[:state] = :disable
    available = b_add
  else
    lbox.selection_clear(old_sel[0]) unless old_sel.empty?
    entry.value = lbox.get(sel[0])
    b_add[:state] = :disable
    b_edit[:state] = :normal
    available = b_edit
  end
  old_sel = sel
}

b_add.command{
  unless (val = entry.value).empty?
    lbox.insert(:end, val)
    entry.value = ''
  end
}

b_edit.command{
  unless (val = entry.value).empty?
    idx = lbox.curselection[0]
    lbox.delete(idx)
    lbox.insert(idx, val)
    lbox.selection_set(idx)
  end
}

entry.focus

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