"""scrollist.py: Scrolled listbox compound widget
$Revision: 1.1 $ $Date: 2000/12/19 01:39:29 $
"""
import string
from Tkinter import *
DEFAULT_WIDTH = 40
DEFAULT_HEIGHT = 25
class ScrolledList(Frame):
"""Scrolled list widget
Exports:
ScrolledList ( parent, width=None, height=None, callback=None ):
[ if (parent is a Frame widget)
and (width is the width in characters, defaulting to
DEFAULT_WIDTH)
and (height is the number of lines visible, defaulting to
DEFAULT_HEIGHT)
and (callback is a procedure with calling sequence
callback ( lineNo )) ->
parent := parent with a new Frame added containing an empty
listbox and scrollbar, ungridded, that will call
callback(i) when double-clicked on the (i)th item
return that new Frame ]
.parent: [ as passed to constructor ]
.width: [ as passed to constructor, or default ]
.height: [ as passed to constructor, or default ]
.callback: [ as passed to constructor ]
.count(): [ returns number of lines in self ]
self[i]:
[ if 0 <= i < self.count() ->
return the (i)th element of self's listbox
else -> raise IndexError ]
.append ( s ):
[ if s is a string ->
self := self with s added as its new last line ]
.insert ( linex, s ):
[ if (linex is an integer) and (s is a string) ->
if 0<=linex<=(number of lines in self) ->
self := self with s inserted as a new line before
position linex
else ->
self := self with s added as its new last line ]
.delete ( linex ):
[ if (0<=linex<(number of lines in self)) ->
self := self with line linex deleted
else -> I ]
.clear(): [ self := self without any lines ]
State/Invariants:
.listbox: [ self's Listbox component ]
.yscroll: [ self's vertical scrollbar component ]
"""
# - - - S c r o l l e d L i s t . _ _ i n i t _ _ - - -
def __init__ ( self, master, width=None, height=None, callback=None ):
"""Constructor for ScrolledList compound widget
"""
#-- 1 --
# [ self := a new Frame in master ]
Frame.__init__ ( self, master )
#-- 2 --
self.master = master
self.callback = callback
if width: self.width = width
else: self.width = DEFAULT_WIDTH
if height: self.height = height
else: self.height = DEFAULT_HEIGHT
#-- 3 --
# [ self := self with all widgets added and gridded ]
self.__createWidgets ()
# - - - S c r o l l e d L i s t . _ _ c r e a t e W i d g e t s - - -
def __createWidgets ( self ):
""" [ self := self with all widgets added and gridded ]
"""
#-- 1 --
# [ self.yscroll := a new vertical Scrollbar in self ]
self.yscroll = Scrollbar ( self, orient=VERTICAL )
self.yscroll.grid ( row=0, column=1, sticky=N+E+S )
#-- 2 --
# [ self.listbox := a new Listbox in self with its vertical
# scrolling slaved to self.yscroll, and
# calling self.__pickHandler() when a line
# is double-clicked ]
self.listbox = Listbox ( self, relief=SUNKEN,
width=self.width, height=self.height, borderwidth=2,
yscrollcommand=self.yscroll.set )
self.listbox.grid ( row=0, column=0, sticky=N+W+S )
self.listbox.bind ( "<Double-Button-1>", self.__pickHandler )
self.yscroll["command"] = self.listbox.yview
# - - - S c r o l l e d L i s t . _ _ p i c k H a n d l e r - - -
def __pickHandler ( self, event ):
"""Handler for double-clicking on self.listbox
"""
#-- 1 --
if self.callback is None:
return
#-- 2 --
# [ if there is a current selection ->
# linex := its index as an integer
# else ->
# return ]
curSel = self.listbox.curselection()
if len(curSel) == 0:
return
else:
linex = string.atoi(curSel[0])
#-- 3 --
self.callback ( linex )
# - - - S c r o l l e d L i s t . c o u n t - - -
def count ( self ):
"""Returns the number of lines in self's listbox
NOTE: Originally I called this method __len__(), so that
anyone could use the len() built-in function to get the
number of entries. But doing so led to bizarre bugs inside
the basic Tkinter Widget class. Apparently someone needs
to call len() on Frame widgets, and my overriding it made
something break.
"""
return self.listbox.size()
# - - - S c r o l l e d L i s t . _ _ g e t i t e m _ _ - -
def __getitem__ ( self, k ):
"""Get the (k)th item from self's listbox
"""
if not ( 0 <= k < self.count() ):
raise IndexError, ( "ScrolledList[%d] out of range" % k )
else:
return self.listbox.get ( k )
# - - - S c r o l l e d L i s t . a p p e n d - - -
def append ( self, s ):
"""Add s as the new last element of self's listbox
"""
self.listbox.insert ( END, s )
# - - - S c r o l l e d L i s t . i n s e r t - - -
def insert ( self, linex, s ):
"""Insert s before position linex
"""
#-- 1 --
if not ( 0 <= linex < self.count() ):
where = END
else:
where = linex
#-- 2 --
self.listbox.insert ( where, s )
# - - - S c r o l l e d L i s t . d e l e t e - - -
def delete ( self, linex ):
"""Delete a line from self's listbox
"""
#-- 1 --
if not ( 0 <= linex < self.count() ):
return
#-- 2 --
self.listbox.delete ( linex )
# - - - S c r o l l e d L i s t . c l e a r - - -
def clear ( self ):
"""Delete all lines from self's listbox
"""
self.listbox.delete ( 0, END )
