I have a TkScrollBox object that displays a list of records. I
want to
sort the list and filter it in various ways, but the only way I've
figured out how to do this is to get rid of the old window and
create a
new window with the sorting option. My question is, is there a way to
refresh a TkScrollBox or the window itself so I don't have to create a
new window each time?
What I do in situations similar to what you describe is to delete the
contents of the list box and repopulate it with new contents. The
following is a rather long example demonstrating this technique. I'm
sorry I don't have a shorter one. The technique is coded into
X11ColorBrowser#category_selected_action.
Hope this helps.
Regards, Morton
<code>
#! /usr/bin/ruby -w
# Author: Morton Goldberg
# Date: August 26, 2006
# X11 color browser
require 'tk'
class X11ColorCategory
# Full path name of the X11 colors file.
RGB_TXT = "/usr/X11R6/lib/X11/rgb.txt"
#Dictionary of rgb values keyed by color name.
COLORS = {}
def X11ColorCategory.read_rgb_table
# read and parse the X11 colors file.
File.foreach(RGB_TXT) do |rgb|
next if rgb =~ /^!/ # skip header line
rgb = rgb.lstrip.split(/\s+/)
r = rgb.shift
g = rgb.shift
b = rgb.shift
key = rgb.join(' ')
COLORS[key] = "r:#{r} g:#{g} b:#{b}"
end
COLORS
end
def X11ColorCategory.all
ALL_CATEGORIES
end
def X11ColorCategory.rgb(color_name)
COLORS[color_name]
end
def extract(pattern)
@members, OTHER.members =
OTHER.members.partition { |m| m =~ pattern }
self
end
def initialize(name)
@name = name
@members = []
end
attr_accessor :name, :members
ALL = X11ColorCategory.new('ALL')
X11ColorCategory.read_rgb_table.each {|key,| ALL.members << key}
ALL.members.sort!
OTHER = X11ColorCategory.new('OTHER')
ALL.members.each {|m| OTHER.members << m}
REDS = X11ColorCategory.new('REDS').
extract(/red|rose|pink|salmon|fire/i)
GREENS = X11ColorCategory.new('GREENS').
extract(/green|chartreuse|olive|honeydew/i)
BLUES = X11ColorCategory.new('BLUES').
extract(/blue|navy/i)
CYANS = X11ColorCategory.new('CYANS').
extract(/cyan|aqua|azure|turquoise/i)
MAGENTAS = X11ColorCategory.new('MAGENTAS').
extract(/magenta|maroon|violet|plum|purple|orchid|thistle/i)
YELLOWS = X11ColorCategory.new('YELLOWS').
extract(/yellow|gold|lemon|corn/i)
ORANGES = X11ColorCategory.new('ORANGES').
extract(/orange|tomato|peach|coral/i)
BROWNS = X11ColorCategory.new('BROWNS').
extract(/brown|tan|wood|choc|sienna|wheat|peru/i)
WHITES = X11ColorCategory.new('WHITES').
extract(/white|ivory|snow|lace/i)
GRAYS = X11ColorCategory.new('GRAYS').
extract(/gr[ae]y|gainsboro/i)
ALL_CATEGORIES = [
REDS,
ORANGES,
YELLOWS,
GREENS,
CYANS,
BLUES,
MAGENTAS,
BROWNS,
WHITES,
GRAYS,
OTHER
]
end
class X11ColorBrowser
# Action performed when category selection is made.
def category_selected_action
@category_names.focus
@selected_category =
X11ColorCategory.all[@category_names.curselection[0]]
@color_names.delete(0, 'end')
@selected_category.members.each { |m| @color_names.insert
("end", m) }
@color_names.selection_set(0)
color_selected_action
end
# Action performed when color selection is made.
def color_selected_action
color = @selected_category.members[@color_names.curselection[0]]
@color_rect.background(color)
@rgb_lbl.text(X11ColorCategory.rgb(color))
end
# Action performed when browser window is mapped.
def window_mapped_action
return if @mapped
@mapped = true
X11ColorCategory.all.each do |category|
@category_names.insert("end", category.name)
end
@category_names.selection_set(0)
category_selected_action
end
def initialize
# Flag indicating that window has been mapped at least once.
@mapped = false
# Holder for currently selected color category
@selected_category = nil
# Set up the browser window.
root = TkRoot.new {title 'Color Browser'}
# Panel at top of browser containing scrolling list of X11
colors and
# label displaying selected color.
top_pnl = TkFrame.new(root)
# List box displaying names of X11 color categories.
@category_names = TkListbox.new(top_pnl)
# Scroll bar for the color names list.
vbar1 = TkScrollbar.new(top_pnl)
@category_names.yscrollbar(vbar1)
# List box displaying names of X11 colors within selected
category.
@color_names = TkListbox.new(top_pnl)
# Scroll bar for the color names list.
vbar2 = TkScrollbar.new(top_pnl)
@color_names.yscrollbar(vbar2)
# Label displaying selected color.
@color_rect = TkLabel.new(top_pnl, 'width'=>25)
# Request layout of top panel.
@category_names.pack("side"=>"left", "fill"=>"both",
"expand"=>true,
"padx"=>5)
vbar1.pack("side"=>"left", "after"=>@category_names, "fill"=>"y")
@color_names.pack("side"=>"left", "after"=>vbar1, "fill"=>"both",
"expand"=>true, "padx"=>5)
vbar2.pack("side"=>"left", "after"=>@color_names, "fill"=>"y")
@color_rect.pack("side"=>"right", "fill"=>"both", "expand"=>true,
"padx"=>5)
top_pnl.pack("side"=>"top", "fill"=>"both", "expand"=>true,
"padx"=>5, "pady"=>8)
# Panel at bottom of browser containing exit button and label
# displaying RGB values of selected color.
btm_pnl = TkFrame.new(root)
# Label displaying rgb values of selected color.
@rgb_lbl = TkLabel.new(btm_pnl) {
text "r:xxx g:xxx b:xxx"
}
# Exit button.
@quit_btn = TkButton.new(btm_pnl) {
text "Exit"
command { Tk.root.destroy }
}
# Request layout of bottom panel.
@rgb_lbl.pack("side"=>"left", "anchor"=>"w")
@quit_btn.pack("side"=>"right")
btm_pnl.pack("side"=>"bottom", "fill"=>"x", "padx"=>10,
"pady"=>8)
# Set initial window geometry; i.e., size and placement.
win_w, win_h = 750, 300
root.minsize(win_w, win_h)
win_x = (root.winfo_screenwidth - win_w) / 2
root.geometry("#{win_w}x#{win_h}+#{win_x}+50")
# Make Cmnd+Q work as expected (for Mac OS X).
root.bind('Command-q') { @quit_btn.invoke }
# Bind mouse button-1, space bar, window map event to their
actions.
@category_names.bind('Map') { window_mapped_action }
ev = TkVirtualEvent.new('ButtonRelease-1', 'space')
@category_names.bind(ev) { category_selected_action }
@color_names.bind(ev) { color_selected_action }
Tk.mainloop
end
end
X11ColorBrowser.new
</code>
