1Gtk2::Buildable(3) User Contributed Perl Documentation Gtk2::Buildable(3)
2
6 Gtk2::Buildable - Interface for objects that can be built by
7 Gtk2::Builder
8
10 package Thing;
11 use Gtk2;
12 use Glib::Object::Subclass
13 Glib::Object::,
14 # Some signals and properties on the object...
16 signals => {
17 exploderize => {},
18 },
19 properties => [
20 Glib::ParamSpec->int ('force', 'Force',
21 'Explosive force, in megatons',
22 0, 1000000, 5, ['readable', 'writable']),
23 ],
24 ;
25 sub exploderize {
27 my $self = shift;
28 $self->signal_emit ('exploderize');
29 }
30 # We can accept all defaults for Buildable; see the description
32 # for details on custom XML.
33 package main;
35 use Gtk2 -init;
36 my $builder = Gtk2::Builder->new ();
37 $builder->add_from_string ('<interface>
38 <object class="Thing" id="thing1">
39 <property name="force">50</property>
40 <signal name="exploderize" handler="do_explode" />
41 </object>
42 </interface>');
43 $builder->connect_signals ();
44 my $thing = $builder->get_object ('thing1');
46 $thing->exploderize ();
48 sub do_explode {
50 my $thing = shift;
51 printf "boom * %d!\n", $thing->get ('force');
52 }
53 # This program prints "boom * 50!" on stdout.
55
57 Glib::Interface
58 +----Gtk2::Buildable
59
61 The Gtk2::Buildable interface allows objects and widgets to have
62 "<child>" objects, special property settings, or extra custom tags in a
63 Gtk2::Builder UI description
64 (<http://library.gnome.org/devel/gtk/unstable/GtkBuilder.html#BUILDER-UI>).
65 The main user of the Gtk2::Buildable interface is Gtk2::Builder, so
67 there should be very little need for applications to call any of the
68 Gtk2::Buildable methods. So this documentation deals with implementing
69 a buildable object.
70 Gtk2::Builder already supports plain Glib::Object or Gtk2::Widget with
72 "<object>" construction and "<property>" settings, so often the
73 "Gtk2::Buildable" interface is not needed. The only thing to note is
74 that an object or widget implemented in Perl must be loaded before
75 building.
76
78 The buildable interface can be added to a Perl code object or widget
79 subclass by putting "Gtk2::Buildable" in the interfaces list and
80 implementing the following methods.
81 In current Gtk2-Perl the custom tags code doesn't chain up to any
83 buildable interfaces in superclasses. This means for instance if you
84 implement Gtk2::Buildable on a new widget subclass then you lose the
85 <accelerator> and <accessibility> tags normally available from
86 Gtk2::Widget. This will likely change in the future, probably by
87 chaining up by default for unhandled tags, maybe with a way to ask
88 deliberately not to chain.
89 SET_NAME ($self, $name)
91 • $name (string)
92 This method should store $name in $self somehow. For example,
94 Gtk2::Widget maps this to the Gtk2::Widget's "name" property. If
95 you don't implement this method, the name will be attached in
96 object data down in C code. Implement this method if your object
97 has some notion of "name" and it makes sense to map the XML name
98 attribute to that.
99 string = GET_NAME ($self)
101 If you implement "SET_NAME", you need to implement this method to
102 retrieve that name.
103 ADD_CHILD ($self, $builder, $child, $type)
105 • $builder (Gtk2::Builder)
106 • $child (Glib::Object or undef)
108 • $type (string)
110 "ADD_CHILD" will be called to add $child to $self. $type can be
112 used to determine the kind of child. For example, Gtk2::Container
113 implements this method to add a child widget to the container, and
114 Gtk2::Notebook uses $type to distinguish between "page-label" and
115 normal children. The value of $type comes directly from the "type"
116 attribute of the XML "child" tag.
117 SET_BUILDABLE_PROPERTY ($self, $builder, $name, $value)
119 • $builder (Gtk2::Builder)
120 • $name (string)
122 • $value (scalar)
124 This will be called to set the object property $name on $self,
126 directly from the "property" XML tag. It is not normally necessary
127 to implement this method, as the fallback simply calls
128 "Glib::Object::set()". Gtk2::Window implements this method to
129 delay showing itself (i.e., setting the "visible" property) until
130 the whole interface is created. You can also use this to handle
131 properties that are not wired up through the Glib::Object property
132 system (though simply creating the property is easier).
133 parser or undef = CUSTOM_TAG_START ($self, $builder, $child, $tagname)
135 • $builder (Gtk2::Builder)
136 • $child (Glib::Object or undef)
138 • $tagname (string)
140 When Gtk2::Builder encounters an unknown tag while parsing the
142 definition of $self, it will call "CUSTOM_TAG_START" to give your
143 code a chance to do something with it. If $tagname was encountered
144 inside a "child" tag, the corresponding object will be passed in
145 $child; otherwise, $child will be "undef".
146 Your "CUSTOM_TAG_START" method should decide whether it supports
148 $tagname. If not, return "undef". If you do support it, return a
149 blessed perl object that implements three special methods to be
150 used to parse that tag. (These methods are defined by GLib's
151 GMarkupParser, which is a simple SAX-style setup.)
152 START_ELEMENT ($self, $context, $element_name, $attributes)
154 • $context (Gtk2::Buildable::ParseContext)
155 • $element_name (string)
157 • $attributes (hash reference) Dictionary of all attributes
159 of this tag.
160 TEXT ($self, $context, $text)
162 • $context (Gtk2::Buildable::ParseContext)
163 • $text (string) The text contained in the tag.
165 END_ELEMENT ($self, $context, $element_name)
167 • $context (Gtk2::Buildable::ParseContext)
168 • $element_name (string)
170 Any blessed perl object that implements these methods is valid as a
172 parser. (Ain't duck-typing great?) Gtk2::Builder will hang on to
173 this object until the parsing is complete, and will pass it to
174 "CUSTOM_TAG_END" and "CUSTOM_FINISHED", so you shouldn't have to
175 worry about its lifetime.
176 CUSTOM_TAG_END ($self, $builder, $child, $tagname, $parser)
178 • $builder (Gtk2::Builder)
179 • $child (Glib::Object or undef)
181 • $tagname (string)
183 • $parser (some perl object) as returned from "CUSTOM_TAG_START"
185 This method will be called (if it exists) when the close tag for
187 $tagname is encountered. $parser will be the object you returned
188 from "CUSTOM_TAG_START". $child is the same object-or-undef as
189 passed to "CUSTOM_TAG_START".
190 CUSTOM_FINISHED ($self, $builder, $child, $tagname, $parser)
192 • $builder (Gtk2::Builder)
193 • $child (Glib::Object or undef)
195 • $tagname (string)
197 • $parser (some perl object) as returned from "CUSTOM_TAG_START"
199 This method will be called (if it exists) when the parser finishes
201 dealing with the custom tag $tagname. $parser will be the object
202 you returned from "CUSTOM_TAG_START". $child is the same object-
203 or-undef as passed to "CUSTOM_TAG_START".
204 PARSER_FINISHED ($self, $builder)
206 • $builder (Gtk2::Builder)
207 If this method exists, it will be invoked when the builder finishes
209 parsing the description data. This method is handy if you need to
210 defer any object initialization until all of the rest of the input
211 is parsed, most likely because you need to refer to an object that
212 is declared after $self or you need to perform special cleanup
213 actions. It is not normally necessary to implement this method.
214 object or undef = GET_INTERNAL_CHILD ($self, $builder, $childname)
216 • $builder (Gtk2::Builder)
217 • $childname (string)
219 This will be called to fetch an internal child of $self. Implement
221 this method if your buildable has internal children that need to be
222 accessed from a UI definition. For example, Gtk2::Dialog
223 implements this to give access to its internal vbox child.
224 If $childname is unknown then return "undef". (The builder will
226 then generally report a GError for the UI description referring to
227 an unknown child.)
228
230 Gtk2, Glib::Interface,
231 <http://library.gnome.org/devel/gtk/unstable/GtkBuilder.html#BUILDER-UI>,
232 Gtk2::Buildable::ParseContext
233
235 Copyright (C) 2003-2011 by the gtk2-perl team.
236 This software is licensed under the LGPL. See Gtk2 for a full notice.
238perl v5.32.1 2021-01-27 Gtk2::Buildable(3)