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GtkBuilder

GtkBuilder — Build an interface from an XML UI definition

Synopsis


#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

Object Hierarchy

  GObject
   +----GtkBuilder

Properties

  "translation-domain"       gchar*                : Read / Write

Description

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 UI Definitions

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 _get_type() 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.

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 57. 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, GtkWindow, GtkContainer, GtkDialog, GtkCellLayout, GtkColorSelectionDialog, GtkFontSelectionDialog, GtkComboBoxEntry, GtkExpander, GtkFrame, GtkListStore, GtkTreeStore, GtkNotebook, GtkSizeGroup, GtkTreeView, GtkUIManager, GtkActionGroup. GtkMenuItem.

Details

GtkBuilder

typedef struct _GtkBuilder GtkBuilder;


GtkBuilderConnectFunc ()

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


enum GtkBuilderError

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,
  GTK_BUILDER_ERROR_DUPLICATE_ID
} GtkBuilderError;

Error codes that identify various errors that can occur while using GtkBuilder.

GTK_BUILDER_ERROR_INVALID_TYPE_FUNCTION

A type-func attribute didn't name a function that returns a GType.

GTK_BUILDER_ERROR_UNHANDLED_TAG

The input contained a tag that GtkBuilder can't handle.

GTK_BUILDER_ERROR_MISSING_ATTRIBUTE

An attribute that is required by GtkBuilder was missing.

GTK_BUILDER_ERROR_INVALID_ATTRIBUTE

#GtkBuilder found an attribute that it doesn't understand.

GTK_BUILDER_ERROR_INVALID_TAG

#GtkBuilder found a tag that it doesn't understand.

GTK_BUILDER_ERROR_MISSING_PROPERTY_VALUE

A required property value was missing.

GTK_BUILDER_ERROR_INVALID_VALUE

#GtkBuilder couldn't parse some attribute value.

GTK_BUILDER_ERROR_VERSION_MISMATCH

The input file requires a newer version of GTK+.

GTK_BUILDER_ERROR_DUPLICATE_ID

An object id occurred twice.

gtk_builder_new ()

GtkBuilder*         gtk_builder_new                     (void);

Creates a new builder object.

Returns :

a new GtkBuilder object

Since 2.12


gtk_builder_add_from_file ()

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


gtk_builder_add_from_string ()

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


gtk_builder_add_objects_from_file ()

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.

Note

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


gtk_builder_add_objects_from_string ()

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.

Note

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


gtk_builder_get_object ()

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


gtk_builder_get_objects ()

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


gtk_builder_connect_signals ()

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


gtk_builder_connect_signals_full ()

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


gtk_builder_set_translation_domain ()

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


gtk_builder_get_translation_domain ()

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


gtk_builder_get_type_from_name ()

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


gtk_builder_value_from_string ()

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


gtk_builder_value_from_string_type ()

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


GTK_BUILDER_WARN_INVALID_CHILD_TYPE()

#define             GTK_BUILDER_WARN_INVALID_CHILD_TYPE(object, type)

This macro should be used to emit a warning about and unexpected type value in a GtkBuildable add_child implementation.

object :

the GtkBuildable on which the warning ocurred

type :

the unexpected type value

GTK_BUILDER_ERROR

#define GTK_BUILDER_ERROR                (gtk_builder_error_quark ())

The GError quark for GtkBuilder errors

Property Details

The "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