NAME

UI::Dialog::Screen::Menu - wrapper to screen dialogs.

SYNOPSIS

  use UI::Dialog::Screen::Menu;

  # $d is an existing instance of UI::Dialog

  my $screen = new UI::Dialog::Screen::Menu ( dialog => $d );
  $screen->add_menu_item("This is the label", sub { print "Hello\n"; });

  # $rv is 0 if the user canceled, 1 if any menu item was selected.
  my $rv = $screen->run();

ABSTRACT

UI::Dialog::Screen::Menu is a helper class which enables a clean and modular code flow for menu driven applications using UI::Dialog. Using callbacks assigned to menu items, a reactionary model to scripting with UI::Dialog becomes rapidly easy.

DESCRIPTION

UI::Dialog::Screen::Menu is actually "external" to the UI::Dialog core usage. The class simply wraps around an existing UI::Dialog instance for rendering a menu-driven flow of screens.

Using this class, you define a number of screen instances and assign callbacks to each of the menu items. Once defined, simply call run() (or loop() to execute run() indefinitely). When a user selects one of the menu items, the assigned function will be executed. From within those functions, simply call other UI::Dialog::Screen::Menu instances and that's how you branch your user's experience from one screen to the next. See the EXAMPLES

EXPORT

None

INHERITS

None

CONSTRUCTOR

new( %options )

EXAMPLE

 # Have UI::Dialog::Screen::Menu use an existing UI::Dialog instance
 # to render the user interface.
 my $s = new( dialog => $d );

 # Also accepts UI::Dialog constructor arguments, so that it can create
 # it's own instance of UI::Dialog if none is provided.
 my $s = new( title => 'Default Title', backtitle => 'Backtitle',
              width => 65, height => 20, listheight => 5,
              order => [ 'zenity', 'xdialog', 'gdialog' ] );

DESCRIPTION

This is the Class Constructor method. It accepts a list of key => value pairs and uses them as the defaults when interacting with the various widgets.

RETURNS

A blessed object reference of the UI::Dialog::Screen::Menu class.

OPTIONS: The (...)'s after each option indicate the default for the option. An * denotes support by all the widget methods on a per-use policy defaulting to the values decided during object creation.

dialog = UI::Dialog (undef)
debug = 0,1,2 (0)
order = [ zenity, xdialog, gdialog, kdialog, cdialog, whiptail, ascii ] (as indicated)
PATH = [ /bin, /usr/bin, /usr/local/bin, /opt/bin ] (as indicated)
backtitle = "backtitle" ('') *
title = "title" ('') *
beepbefore = 0,1 (0) *
beepafter = 0,1 (0) *
height = \d+ (20) *
width = \d+ (65) *
listheight = \d+ (5) *

STATE METHODS

run( )

EXAMPLE

 my $rv = $s->run();

DESCRIPTION

Render the screen menu immediately. This method blocks until the user input has been received and acted upon.

RETURNS

TRUE if the user selected an item from the menu, FALSE otherwise.

loop( )

EXAMPLE

 $s->loop();

DESCRIPTION

Calls the run() method immediately. Once run() completes it's execution, the loop() decides whether or not to display again. If the return value of run() is TRUE, the loop() will continue. If the use pressed Cancel (or Escape) or any other action other than one of the menu items; the loop() will end. The loop() will also end if the break_loop() method is called.

RETURNS

TRUE if the user selected an item from the menu, FALSE otherwise.

is_looping( )

EXAMPLE

 if ($s->is_looping()) {
     print "Currently in a UI::Dialog::Screen::Menu loop\n";
 }

DESCRIPTION

Returns TRUE if the given screen is in a menu loop(), FALSE otherwise.

RETURNS

a single SCALAR.

break_loop( )

EXAMPLE

 $s->break_loop();

DESCRIPTION

Flags the screen menu to stop looping. This does not close or otherwise clear the screen. This simply flags the loop to exit at the end of it's current run.

RETURNS

None.

SCREEN METHODS

add_menu_item( )

EXAMPLE

 my $index = $s->add_menu_item( "Menu Item Label", \%some_function );

DESCRIPTION

Append a new item to the menu list.

RETURNS

Returns the list index (starting from 0) of the item that was just appended to the list.

get_menu_items( )

EXAMPLE

 my @items = $s->get_menu_items();

DESCRIPTION

Returns an array of hashrefs. Each hash contains a "label" and "func" key/value pairs.

RETURNS

An ARRAY.

del_menu_item( )

EXAMPLE

 my $old_item = $d->del_menu_item( $index );

DESCRIPTION

Remove a specific item from the menu, addressed by it's list index (starting from 0), and return the menu item as a hashref.

RETURNS

A HASH containing the 'label' and 'func' of the menu item that was just removed from the menu list.

set_menu_item( )

EXAMPLE

 # Modify the 'label' and 'func' for a specific menu item
 my $original_item = $s->set_menu_item( $index, $label, $func );

 # Modify just the label of a menu item
 my $original_item = $s->set_menu_item( $index, $label, undef );

 # Modify just the func of a menu item
 my $original_item = $s->set_menu_item( $index, undef, $func );

 # Effectively do nothing
 my $original_item = $s->set_menu_item( $index, undef, undef );

DESCRIPTION

Modify the menu item addressed by the given index (starting from 0). If the 'label' and/or 'func' arguments are undef then the previous value is kept.

RETURNS

A HASH of the original values for the modified menu item.

EXAMPLE USAGE

The below example assumed that $d is an instances of UI::Dialog.

 # Create our first screen
 my $s1 = new UI::Dialog::Screen::Menu ( dialog => $d );
 $s1->add_menu_item( "Just an option", \&some_function );

 # Add a menu item that updates it's own label every time
 # it is selected.
 our $counter = 0;
 $s1->add_menu_item
  ( "Counter: ".$counter,
    sub {
      my ($self,$dialog,$index) = @_;
      $counter++;
      $self->set_menu_item($index,"Counter: ".$counter, undef);
    }
  );

 # Create a second screen
 my $s2 = new UI::Dialog::Screen::Menu ( dialog => $d );
 $s2->add_menu_item( "Another item", \&another_function );

 # Link the second screen to an option of the first
 $s1->add_menu_item( "Goto Screen 2", sub { $s2->loop(); } );

 # Start a menu loop and actually display the first screen
 $s1->loop();

Users can get to second menu from selecting the third item on the first menu screen. As long as the user continues to select items from the second menu, it will continue to loop. If the user cancels the second screen, the will return to the first which will itself continue to loop.

BUGS

Please email the author with any bug reports. Include the name of the module in the subject line.

AUTHOR

Kevin C. Krinke, <kevin@krinke.ca>

COPYRIGHT AND LICENSE

 Copyright (C) 2004-2016  Kevin C. Krinke <kevin@krinke.ca>

 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.

 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA