Menu::Item(3) perl/Tk Documentation Menu::Item(3)NAMETk::Menu::Item - Base class for Menu items
SYNOPYSIS
require Tk::Menu::Item;
my $but = $menu->Button(...);
$but->configure(...);
my $what = $but->cget();
package Whatever;
require Tk::Menu::Item;
@ISA = qw(Tk::Menu::Item);
sub PreInit
{
my ($class,$menu,$info) = @_;
$info->{'-xxxxx'} = ...
my $y = delete $info->{'-yyyy'};
}
DESCRIPTIONTk::Menu::Item is the base class from which
Tk::Menu::Button, Tk::Menu::Cascade, Tk::Menu::Radiobutton
and Tk::Menu::Checkbutton are derived. There is also a
Tk::Menu::Separator.
Constructors are declared so that $menu->Button(...) etc.
do what you would expect.
The -label option is pre-processed allowing ~ to be
prefixed to the character to derive a -underline value.
Thus
$menu->Button(-label => 'Goto ~Home',...)
is equivalent to
$menu->Button(-label => 'Goto Home', -underline => 6, ...)
Cascade accepts -menuitems which is a list of items for
the sub-menu. Within this list (which is also accepted by
Menu and Menubutton) the first two elements of each item
should be the "constructor" name and the label:
-menuitems => [
[Button => '~Quit', -command => [destroy => $mw]],
[Checkbutton => '~Oil', -variable => \$oil],
]
Also -tearoff is propagated to the submenu, and -menuvar
(if present) is set to the created sub-menu.
25/Aug/1997 Tk400.202 1
Menu::Item(3) perl/Tk Documentation Menu::Item(3)
The returned object is currently a blessed reference to an
array of two items: the containing Menu and the 'label'.
Methods configure and cget are mapped onto underlying
entryconfigure and entrycget.
The main purpose of the OO interface is to allow derived
item classes to be defined which pre-set the options used
to create a more basic item.
BUGS
This OO interface is very new. Using the label as the
"key" is a problem for separaror items which don't have
one. The alternative would be to use an index into the
menu but that is a problem if items are deleted (or
inserted other than at the end).
There should probably be a PostInit entry point too, or a
more widget like defered 'configure'.
25/Aug/1997 Tk400.202 2
