1Curses::UI::Tutorial(3)User Contributed Perl DocumentatioCnurses::UI::Tutorial(3)
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6 Curses::UI::Tutorial - Tutorial for the Curses::UI framework
7
9 The intention of this tutorial is a quick overview of Curses::UI and
10 it's widgets. The target of this example is to write a simple text
11 editor using the Curses::UI framework.
12
14 In order to use Curses::UI start your program with "use Curses::UI;"
15 and, as it is always a good idea,
16 add "use strict" and the -w switch too. After that an instance of
17 Curses::UI must be created. From now on, this instance will be called
18 "the UI". You also want to redirect STDERR to a file (e.g. perl
19 myscript.pl 2> debug.out), so output that does not come from Curses::UI
20 doesn't clobber your display. You want fancy colors, so the option
21 -color_support is set to a true value.
22 #!/usr/bin/perl -w
24 use strict;
26 use Curses::UI;
27 my $cui = new Curses::UI( -color_support => 1 );
28
30 my @menu = (
31 { -label => 'File',
32 -submenu => [
33 { -label => 'Exit ^Q', -value => \&exit_dialog }
34 ]
35 },
36 );
37 In order to describe the structure of a menu Curses::UI uses a rather
39 ugly construct out of hash and arrayrefs. See Curses::UI::Menubar for
40 details. What you do at this point is to create a Menubar with just one
41 entry and one submenu. The entry is 'File' and the submenu is 'Exit'.
42 The value of this menu item is a reference to a sub called exit_dialog.
43
45 sub exit_dialog()
46 {
47 my $return = $cui->dialog(
48 -message => "Do you really want to quit?",
49 -title => "Are you sure???",
50 -buttons => ['yes', 'no'],
51 );
53 exit(0) if $return;
55 }
56 The dialog method of Curses::UI gives us an easy and convenient way to
58 create dialogs on the main screen. A dialog is a way to interact with
59 the user in order to ask him a question or give him important
60 information. This dialog is a more complex one, which asks the
61 question whether or not you really want to exit. As the button for
62 "yes" would return us a true value, you can easily exit on this return
63 value.
64
66 my $menu = $cui->add(
67 'menu','Menubar',
68 -menu => \@menu,
69 -fg => "blue",
70 );
71 To finally add the Menubar to our root object, you have to call the add
73 method on the Curses UI object. You specify the internal name of the
74 widget as the first argument, the widget type as the second argument
75 (like Label, TextViewer, etc.) and the menu structure you created at
76 the beginning as an array reference as third object. Because you want
77 the Menubar to have a blue theme, you give him the -fg option "blue".
78 There are a couple of colors you can use, see Curses::UI::Color for
79 details.
80
82 my $win1 = $cui->add(
83 'win1', 'Window',
84 -border => 1,
85 -y => 1,
86 -bfg => 'red',
87 );
88 There are only two types of object you can add to the Curses::UI root
90 object: Menubars and Windows. All other widgets have to be inserted
91 into a window. Of course you can add a Menubar to a window, but not
92 vice versa ;-). The add method always has the same two first
93 arguments: the internal name and the widget type. The internal name can
94 be used to find an object. The method getobj takes this name and
95 returns us the corresponding object out of the hierarchy. See
96 Curses::UI for details. Again you want some fancy colors, so you tell
97 the window to have a border, leave some space for the Menubar (-y => 1)
98 and set the border foreground color to red.
99
101 my $texteditor = $win1->add("text", "TextEditor",
102 -text => "Here is some text\n"
103 . "And some more");
104 The next step is to add a useful widget to our new small Curses::UI
106 app. Here you take a TextEditor widget which performs basic tasks as a
107 text editor. You add some initial text to the widget to make it not
108 seem that empty.
109
111 $cui->set_binding(sub {$menu->focus()}, "\cX");
112 $cui->set_binding( \&exit_dialog , "\cQ");
113 You want to be able to focus the Menubar if you finished editing in the
115 TextEditor widget. Therefore you set a binding to the focus function of
116 the menu and the key sequence Control (specified by \c) combined with
117 X. Now you can easily return to the menu after editing. Because it is
118 easier to have a shortcut for closing the application you add a binding
119 for the sequence Control-Q to our nice exit_dialog method.
120
122 $texteditor->focus();
123 $cui->mainloop();
124 You want to start editing directly. Therefore you set the initial focus
126 on the TextEditor by calling it's focus method directly. The last
127 thing you got to do is to tell Curses that it now contoles the program
128 flow by starting it's MainLoop.
129
131 You have built a genuine Curses::UI application! Not that it is a very
132 useful one, but who cares? Now try out if it works like you think it
133 should. The complete source code of this application is located in the
134 examples directory of the distribution (examples/tutorial.pl).
135 Now you can enhance this application to become a full featured editor
137 like Emacs :-)
138
140 2003-2004 (c) by Marcus Thiesen (marcus@cpan.org) All rights reserved
141 This Tutorial is licensed under the same terms as perl itself.
142 If you have some additions to this tutorial feel free to send me a
144 mail.
145perl v5.32.0 2020-07-28 Curses::UI::Tutorial(3)