Mastering Perl/Tk

Listbox Example

Sometimes when you put a lot of items in a Listbox, it takes a long time to scroll through it. If you insert the items in the Listbox sorted, you can implement a search routine. Here’s a quick script that shows you how to use an Entry widget to input the search text and search the Listbox every time you get a new character in the Entry:

use Tk; $mw = MainWindow->new; $mw->title("Listbox"); # For example purposes, we'll use one word for each letter @choices = qw/alpha beta charlie delta echo foxtrot golf hotel india juliet kilo lima motel nancy oscar papa quebec radio sierra tango uniform victor whiskey xray yankee zulu/; # Create the Entry widget, and bind the do_search sub to any keypress $entry = $mw->Entry(-textvariable => \$search)->pack(-side => "top", -fill => "x"); $entry->bind("<KeyPress>", [ \&do_search, Ev("K") ]); # Create Listbox and insert the list of choices into it my $lb = $mw->Scrolled("Listbox", -scrollbars => "osoe", )->pack(-side => "left"); $lb->insert("end", sort @choices); $mw->Button(-text => "Exit", -command => sub { exit; })->pack(-side => "bottom"); MainLoop; # This routine is called each time we push a keyboard key. sub do_search { my ($entry, $key) = @_; # Ignore the backspace key and anything that doesn't change the word # i.e. The Control or Alt keys return if ($key =~ /backspace/i); return if ($oldsearch eq $search); # Use what's currently displayed in Listbox to search through # This is a non-complicated in order search my @list ...