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Curses::UI::Tutorial(3) User Contributed Perl Documentation Curses::UI::Tutorial(3)
NAME
Curses::UI::Tutorial - Tutorial for the Curses::UI framework
Introduction
The intention of this tutorial is a quick overview of Curses::UI and it's widgets. The
target of this example is to write a simple text editor using the Curses::UI framework.
First requirements
In order to use Curses::UI start your program with "use Curses::UI;" and, as it is always
a good idea,
add "use strict" and the -w switch too. After that an instance of Curses::UI must be
created. From now on, this instance will be called "the UI". You also want to redirect
STDERR to a file (e.g. perl myscript.pl 2> debug.out), so output that does not come from
Curses::UI doesn't clobber your display. You want fancy colors, so the option
-color_support is set to a true value.
#!/usr/bin/perl -w
use strict;
use Curses::UI;
my $cui = new Curses::UI( -color_support => 1 );
Create a menu
my @menu = (
{ -label => 'File',
-submenu => [
{ -label => 'Exit ^Q', -value => \&exit_dialog }
]
},
);
In order to describe the structure of a menu Curses::UI uses a rather ugly construct out
of hash and arrayrefs. See Curses::UI::Menubar for details. What you do at this point is
to create a Menubar with just one entry and one submenu. The entry is 'File' and the
submenu is 'Exit'. The value of this menu item is a reference to a sub called
exit_dialog.
Dialogs
sub exit_dialog()
{
my $return = $cui->dialog(
-message => "Do you really want to quit?",
-title => "Are you sure???",
-buttons => ['yes', 'no'],
);
exit(0) if $return;
}
The dialog method of Curses::UI gives us an easy and convenient way to create dialogs on
the main screen. A dialog is a way to interact with the user in order to ask him a
question or give him important information. This dialog is a more complex one, which asks
the question whether or not you really want to exit. As the button for "yes" would return
us a true value, you can easily exit on this return value.
Add the Menubar
my $menu = $cui->add(
'menu','Menubar',
-menu => \@menu,
-fg => "blue",
);
To finally add the Menubar to our root object, you have to call the add method on the
Curses UI object. You specify the internal name of the widget as the first argument, the
widget type as the second argument (like Label, TextViewer, etc.) and the menu structure
you created at the beginning as an array reference as third object. Because you want the
Menubar to have a blue theme, you give him the -fg option "blue". There are a couple of
colors you can use, see Curses::UI::Color for details.
Add a window
my $win1 = $cui->add(
'win1', 'Window',
-border => 1,
-y => 1,
-bfg => 'red',
);
There are only two types of object you can add to the Curses::UI root object: Menubars and
Windows. All other widgets have to be inserted into a window. Of course you can add a
Menubar to a window, but not vice versa ;-). The add method always has the same two first
arguments: the internal name and the widget type. The internal name can be used to find an
object. The method getobj takes this name and returns us the corresponding object out of
the hierarchy. See Curses::UI for details. Again you want some fancy colors, so you tell
the window to have a border, leave some space for the Menubar (-y => 1) and set the border
foreground color to red.
Add a widget
my $texteditor = $win1->add("text", "TextEditor",
-text => "Here is some text\n"
. "And some more");
The next step is to add a useful widget to our new small Curses::UI app. Here you take a
TextEditor widget which performs basic tasks as a text editor. You add some initial text
to the widget to make it not seem that empty.
Making keybindings
$cui->set_binding(sub {$menu->focus()}, "\cX");
$cui->set_binding( \&exit_dialog , "\cQ");
You want to be able to focus the Menubar if you finished editing in the TextEditor widget.
Therefore you set a binding to the focus function of the menu and the key sequence Control
(specified by \c) combined with X. Now you can easily return to the menu after editing.
Because it is easier to have a shortcut for closing the application you add a binding for
the sequence Control-Q to our nice exit_dialog method.
The final steps
$texteditor->focus();
$cui->mainloop();
You want to start editing directly. Therefore you set the initial focus on the TextEditor
by calling it's focus method directly. The last thing you got to do is to tell Curses
that it now contoles the program flow by starting it's MainLoop.
You're done!
You have built a genuine Curses::UI application! Not that it is a very useful one, but who
cares? Now try out if it works like you think it should. The complete source code of this
application is located in the examples directory of the distribution
(examples/tutorial.pl).
Now you can enhance this application to become a full featured editor like Emacs :-)
Author
2003-2004 (c) by Marcus Thiesen (marcus AT cpan.org) All rights reserved This Tutorial is
licensed under the same terms as perl itself.
If you have some additions to this tutorial feel free to send me a mail.
perl v5.16.3 2011-09-01 Curses::UI::Tutorial(3)
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On Apache
Under GNU General Public License
2024-04-25 21:20 @3.128.199.88 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)