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GTK+ Reference Manual | ![]() |
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#include <gtk/gtk.h> GtkBuilder; void (*GtkBuilderConnectFunc) (GtkBuilder *builder, GObject *object, const gchar *signal_name, const gchar *handler_name, GObject *connect_object, GConnectFlags flags, gpointer user_data); enum GtkBuilderError; GtkBuilder* gtk_builder_new (void); guint gtk_builder_add_from_file (GtkBuilder *builder, const gchar *filename, GError **error); guint gtk_builder_add_from_string (GtkBuilder *builder, const gchar *buffer, gsize length, GError **error); guint gtk_builder_add_objects_from_file (GtkBuilder *builder, const gchar *filename, gchar **object_ids, GError **error); guint gtk_builder_add_objects_from_string (GtkBuilder *builder, const gchar *buffer, gsize length, gchar **object_ids, GError **error); GObject* gtk_builder_get_object (GtkBuilder *builder, const gchar *name); GSList* gtk_builder_get_objects (GtkBuilder *builder); void gtk_builder_connect_signals (GtkBuilder *builder, gpointer user_data); void gtk_builder_connect_signals_full (GtkBuilder *builder, GtkBuilderConnectFunc func, gpointer user_data); void gtk_builder_set_translation_domain (GtkBuilder *builder, const gchar *domain); const gchar* gtk_builder_get_translation_domain (GtkBuilder *builder); GType gtk_builder_get_type_from_name (GtkBuilder *builder, const char *type_name); gboolean gtk_builder_value_from_string (GtkBuilder *builder, GParamSpec *pspec, const gchar *string, GValue *value, GError **error); gboolean gtk_builder_value_from_string_type (GtkBuilder *builder, GType type, const gchar *string, GValue *value, GError **error); #define GTK_BUILDER_WARN_INVALID_CHILD_TYPE (object, type) #define GTK_BUILDER_ERROR
A GtkBuilder is an auxiliary object that reads textual descriptions
of a user interface and instantiates the described objects. To pass a
description to a GtkBuilder, call gtk_builder_add_from_file()
or
gtk_builder_add_from_string()
. These functions can be called multiple
times; the builder merges the content of all descriptions.
A GtkBuilder holds a reference to all objects that it has constructed
and drops these references when it is finalized. This finalization can
cause the destruction of non-widget objects or widgets which are not
contained in a toplevel window. For toplevel windows constructed by a
builder, it is the responsibility of the user to call gtk_widget_destroy()
to get rid of them and all the widgets they contain.
The functions gtk_builder_get_object()
and gtk_builder_get_objects()
can be used to access the widgets in the interface by the names assigned
to them inside the UI description. Toplevel windows returned by these
functions will stay around until the user explicitly destroys them
with gtk_widget_destroy()
. Other widgets will either be part of a
larger hierarchy constructed by the builder (in which case you should
not have to worry about their lifecycle), or without a parent, in which
case they have to be added to some container to make use of them.
Non-widget objects need to be reffed with g_object_ref()
to keep them
beyond the lifespan of the builder.
The function gtk_builder_connect_signals()
and variants thereof can be
used to connect handlers to the named signals in the description.
GtkBuilder parses textual descriptions of user interfaces which are specified in an XML format which can be roughly described by the DTD below. We refer to these descriptions as GtkBuilder UI definitions or just UI definitions if the context is clear. Do not confuse GtkBuilder UI Definitions with GtkUIManager UI Definitions, which are more limited in scope.
<!ELEMENT interface (requires|object)* > <!ELEMENT object (property|signal|child|ANY)* > <!ELEMENT property PCDATA > <!ELEMENT signal EMPTY > <!ELEMENT requires EMPTY > <!ELEMENT child (object|ANY*) > <!ATTLIST interface domain #IMPLIED > <!ATTLIST object id #REQUIRED class #REQUIRED type-func #IMPLIED constructor #IMPLIED > <!ATTLIST requires lib #REQUIRED version #REQUIRED > <!ATTLIST property name #REQUIRED translatable #IMPLIED comments #IMPLIED context #IMPLIED > <!ATTLIST signal name #REQUIRED handler #REQUIRED after #IMPLIED swapped #IMPLIED object #IMPLIED last_modification_time #IMPLIED > <!ATTLIST child type #IMPLIED internal-child #IMPLIED >
The toplevel element is <interface>.
It optionally takes a "domain" attribute, which will make
the builder look for translated strings using dgettext()
in the
domain specified. This can also be done by calling
gtk_builder_set_translation_domain()
on the builder.
Objects are described by <object> elements, which can
contain <property> elements to set properties, <signal>
elements which connect signals to handlers, and <child>
elements, which describe child objects (most often widgets
inside a container, but also e.g. actions in an action group,
or columns in a tree model). A <child> element contains
an <object> element which describes the child object.
The target toolkit version(s) are described by <requires>
elements, the "lib" attribute specifies the widget library in
question (currently the only supported value is "gtk+") and the "version"
attribute specifies the target version in the form "<major>.<minor>".
The builder will error out if the version requirements are not met.
Typically, the specific kind of object represented by an
<object> element is specified by the "class" attribute.
If the type has not been loaded yet, GTK+ tries to find the
from the class name by applying
heuristics. This works in most cases, but if necessary, it is
possible to specify the name of the _get_type()
explictly with the "type-func" attribute. As a special case,
GtkBuilder allows to use an object that has been constructed
by a GtkUIManager in another part of the UI definition by
specifying the id of the GtkUIManager in the "constructor"
attribute and the name of the object in the "id" attribute.
_get_type()
Objects must be given a name with the "id" attribute, which
allows the application to retrieve them from the builder with
gtk_builder_get_object()
. An id is also necessary to use the
object as property value in other parts of the UI definition.
Setting properties of objects is pretty straightforward with
the <property> element: the "name" attribute specifies
the name of the property, and the content of the element
specifies the value. If the "translatable" attribute is
set to a true value, GTK+ uses gettext()
(or dgettext()
if
the builder has a translation domain set) to find a translation
for the value. This happens before the value is parsed, so
it can be used for properties of any type, but it is probably
most useful for string properties. It is also possible to
specify a context to disambiguate short strings, and comments
which may help the translators.
GtkBuilder can parse textual representations for the most
common property types: characters, strings, integers, floating-point
numbers, booleans (strings like "TRUE", "t", "yes", "y", "1" are
interpreted as TRUE
, strings like "FALSE, "f", "no", "n", "0" are
interpreted as FALSE
), enumerations (can be specified by their
name, nick or integer value), flags (can be specified by their name,
nick, integer value, optionally combined with "|", e.g.
"GTK_VISIBLE|GTK_REALIZED") and colors (in a format understood by
gdk_color_parse()
). Objects can be referred to by their name.
Pixbufs can be specified as a filename of an image file to load.
In general, GtkBuilder allows forward references to objects —
an object doesn't have to constructed before it can be referred to.
The exception to this rule is that an object has to be constructed
before it can be used as the value of a construct-only property.
Signal handlers are set up with the <signal> element.
The "name" attribute specifies the name of the signal, and the
"handler" attribute specifies the function to connect to the signal.
By default, GTK+ tries to find the handler using g_module_symbol()
,
but this can be changed by passing a custom GtkBuilderConnectFunc
to gtk_builder_connect_signals_full()
. The remaining attributes,
"after", "swapped" and "object", have the same meaning as the
corresponding parameters of the g_signal_connect_object()
or
g_signal_connect_data()
functions. A "last_modification_time" attribute
is also allowed, but it does not have a meaning to the builder.
Sometimes it is necessary to refer to widgets which have implicitly
been constructed by GTK+ as part of a composite widget, to set
properties on them or to add further children (e.g. the vbox
of a GtkDialog). This can be achieved by setting the "internal-child"
propery of the <child> element to a true value. Note that
GtkBuilder still requires an <object> element for the internal
child, even if it has already been constructed.
A number of widgets have different places where a child can be added (e.g. tabs vs. page content in notebooks). This can be reflected in a UI definition by specifying the "type" attribute on a <child> The possible values for the "type" attribute are described in the sections describing the widget-specific portions of UI definitions.
Example 53. A GtkBuilder UI Definition
<interface> <object class="GtkDialog" id="dialog1"> <child internal-child="vbox"> <object class="GtkVBox" id="vbox1"> <property name="border-width">10</property> <child internal-child="action_area"> <object class="GtkHButtonBox" id="hbuttonbox1"> <property name="border-width">20</property> <child> <object class="GtkButton" id="ok_button"> <property name="label">gtk-ok</property> <property name="use-stock">TRUE</property> <signal name="clicked" handler="ok_button_clicked"/> </object> </child> </object> </child> </object> </child> </object> </interface>
Beyond this general structure, several object classes define their own XML DTD fragments for filling in the ANY placeholders in the DTD above. Note that a custom element in a <child> element gets parsed by the custom tag handler of the parent object, while a custom element in an <object> element gets parsed by the custom tag handler of the object.
These XML fragments are explained in the documentation of the respective objects, see GtkWidget, GtkLabel, GtkContainer, GtkDialog, GtkCellLayout, GtkColorSelectionDialog, GtkFontSelectionDialog, GtkComboBoxEntry, GtkExpander, GtkFrame, GtkListStore, GtkTreeStore, GtkNotebook, GtkSizeGroup, GtkTreeView, GtkUIManager, GtkActionGroup.
void (*GtkBuilderConnectFunc) (GtkBuilder *builder, GObject *object, const gchar *signal_name, const gchar *handler_name, GObject *connect_object, GConnectFlags flags, gpointer user_data);
This is the signature of a function used to connect signals. It is used
by the gtk_builder_connect_signals()
and gtk_builder_connect_signals_full()
methods. It is mainly intended for interpreted language bindings, but
could be useful where the programmer wants more control over the signal
connection process.
builder : |
a GtkBuilder |
object : |
object to connect a signal to |
signal_name : |
name of the signal |
handler_name : |
name of the handler |
connect_object : |
a GObject, if non-NULL , use g_signal_connect_object()
|
flags : |
GConnectFlags to use |
user_data : |
user data |
Since 2.12
typedef enum { GTK_BUILDER_ERROR_INVALID_TYPE_FUNCTION, GTK_BUILDER_ERROR_UNHANDLED_TAG, GTK_BUILDER_ERROR_MISSING_ATTRIBUTE, GTK_BUILDER_ERROR_INVALID_ATTRIBUTE, GTK_BUILDER_ERROR_INVALID_TAG, GTK_BUILDER_ERROR_MISSING_PROPERTY_VALUE, GTK_BUILDER_ERROR_INVALID_VALUE, GTK_BUILDER_ERROR_VERSION_MISMATCH } GtkBuilderError;
GtkBuilder* gtk_builder_new (void);
Creates a new builder object.
Returns : | a new GtkBuilder object |
Since 2.12
guint gtk_builder_add_from_file (GtkBuilder *builder, const gchar *filename, GError **error);
Parses a file containing a GtkBuilder
UI definition and merges it with the current contents of builder
.
builder : |
a GtkBuilder |
filename : |
the name of the file to parse |
error : |
return location for an error, or NULL
|
Returns : | A positive value on success, 0 if an error occurred |
Since 2.12
guint gtk_builder_add_from_string (GtkBuilder *builder, const gchar *buffer, gsize length, GError **error);
Parses a string containing a GtkBuilder
UI definition and merges it with the current contents of builder
.
builder : |
a GtkBuilder |
buffer : |
the string to parse |
length : |
the length of buffer (may be -1 if buffer is nul-terminated)
|
error : |
return location for an error, or NULL
|
Returns : | A positive value on success, 0 if an error occurred |
Since 2.12
guint gtk_builder_add_objects_from_file (GtkBuilder *builder, const gchar *filename, gchar **object_ids, GError **error);
Parses a file containing a GtkBuilder
UI definition building only the requested objects and merges
them with the current contents of builder
.
If you are adding an object that depends on an object that is not
its child (for instance a GtkTreeView that depends on its
GtkTreeModel), you have to explicitely list all of them in object_ids
.
builder : |
a GtkBuilder |
filename : |
the name of the file to parse |
object_ids : |
nul-terminated array of objects to build |
error : |
return location for an error, or NULL
|
Returns : | A positive value on success, 0 if an error occurred |
Since 2.14
guint gtk_builder_add_objects_from_string (GtkBuilder *builder, const gchar *buffer, gsize length, gchar **object_ids, GError **error);
Parses a string containing a GtkBuilder
UI definition building only the requested objects and merges
them with the current contents of builder
.
If you are adding an object that depends on an object that is not
its child (for instance a GtkTreeView that depends on its
GtkTreeModel), you have to explicitely list all of them in object_ids
.
builder : |
a GtkBuilder |
buffer : |
the string to parse |
length : |
the length of buffer (may be -1 if buffer is nul-terminated)
|
object_ids : |
nul-terminated array of objects to build |
error : |
return location for an error, or NULL
|
Returns : | A positive value on success, 0 if an error occurred |
Since 2.14
GObject* gtk_builder_get_object (GtkBuilder *builder, const gchar *name);
Gets the object named name
. Note that this function does not
increment the reference count of the returned object.
builder : |
a GtkBuilder |
name : |
name of object to get |
Returns : | the object named name or NULL if it could not be
found in the object tree.
|
Since 2.12
GSList* gtk_builder_get_objects (GtkBuilder *builder);
Gets all objects that have been constructed by builder
. Note that
this function does not increment the reference counts of the returned
objects.
builder : |
a GtkBuilder |
Returns : | a newly-allocated GSList containing all the objects
constructed by the GtkBuilder instance. It should be freed by
g_slist_free()
|
Since 2.12
void gtk_builder_connect_signals (GtkBuilder *builder, gpointer user_data);
This method is a simpler variation of gtk_builder_connect_signals_full()
.
It uses GModule's introspective features (by opening the module NULL
)
to look at the application's symbol table. From here it tries to match
the signal handler names given in the interface description with
symbols in the application and connects the signals.
Note that this function will not work correctly if GModule is not supported on the platform.
When compiling applications for Windows, you must declare signal callbacks with G_MODULE_EXPORT, or they will not be put in the symbol table. On Linux and Unices, this is not necessary; applications should instead be compiled with the -Wl,--export-dynamic CFLAGS, and linked against gmodule-export-2.0.
builder : |
a GtkBuilder |
user_data : |
a pointer to a structure sent in as user data to all signals |
Since 2.12
void gtk_builder_connect_signals_full (GtkBuilder *builder, GtkBuilderConnectFunc func, gpointer user_data);
This function can be thought of the interpreted language binding
version of gtk_builder_connect_signals()
, except that it does not
require GModule to function correctly.
builder : |
a GtkBuilder |
func : |
the function used to connect the signals |
user_data : |
arbitrary data that will be passed to the connection function |
Since 2.12
void gtk_builder_set_translation_domain (GtkBuilder *builder, const gchar *domain);
Sets the translation domain of builder
.
See "translation-domain".
builder : |
a GtkBuilder |
domain : |
the translation domain or NULL
|
Since 2.12
const gchar* gtk_builder_get_translation_domain (GtkBuilder *builder);
Gets the translation domain of builder
.
builder : |
a GtkBuilder |
Returns : | the translation domain. This string is owned by the builder object and must not be modified or freed. |
Since 2.12
GType gtk_builder_get_type_from_name (GtkBuilder *builder, const char *type_name);
Looks up a type by name, using the virtual function that GtkBuilder has for that purpose. This is mainly used when implementing the GtkBuildable interface on a type.
builder : |
a GtkBuilder |
type_name : |
type name to lookup |
Returns : | the GType found for type_name or G_TYPE_INVALID
if no type was found
|
Since 2.12
gboolean gtk_builder_value_from_string (GtkBuilder *builder, GParamSpec *pspec, const gchar *string, GValue *value, GError **error);
This function demarshals a value from a string. This function
calls g_value_init()
on the value
argument, so it need not be
initialised beforehand.
This function can handle char, uchar, boolean, int, uint, long, ulong, enum, flags, float, double, string, GdkColor and GtkAdjustment type values. Support for GtkWidget type values is still to come.
builder : |
a GtkBuilder |
pspec : |
the GParamSpec for the property |
string : |
the string representation of the value |
value : |
the GValue to store the result in |
error : |
return location for an error, or NULL
|
Returns : | TRUE on success
|
Since 2.12
gboolean gtk_builder_value_from_string_type (GtkBuilder *builder, GType type, const gchar *string, GValue *value, GError **error);
Like gtk_builder_value_from_string()
, this function demarshals
a value from a string, but takes a GType instead of GParamSpec.
This function calls g_value_init()
on the value
argument, so it
need not be initialised beforehand.
builder : |
a GtkBuilder |
type : |
the GType of the value |
string : |
the string representation of the value |
value : |
the GValue to store the result in |
error : |
return location for an error, or NULL
|
Returns : | TRUE on success
|
Since 2.12
#define GTK_BUILDER_WARN_INVALID_CHILD_TYPE(object, type)
object : |
|
type : |
"translation-domain"
property"translation-domain" gchar* : Read / Write
The translation domain used when translating property values that
have been marked as translatable in interface descriptions.
If the translation domain is NULL
, GtkBuilder uses gettext()
,
otherwise g_dgettext()
.
Default value: NULL
Since 2.12