A GtkBuilder is an auxiliary object that reads textual descriptions of a user interface and instantiates the described objects. To create a GtkBuilder from a user interface description, call Gtk.Builder.Gtk_New_From_File, Gtk.Builder.Gtk_New_From_Resource or Gtk.Builder.Gtk_New_From_String.
In the (unusual) case that you want to add user interface descriptions from multiple sources to the same GtkBuilder you can call Gtk.Builder.Gtk_New to get an empty builder and populate it by (multiple) calls to Gtk.Builder.Add_From_File, Gtk.Builder.Add_From_Resource or Gtk.Builder.Add_From_String.
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 # {BUILDER-UI}
GtkBuilder parses textual descriptions of user interfaces which are specified in an XML format which can be roughly described by the RELAX NG schema 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][XML-UI], which are more limited in scope. It is common to use .ui as the filename extension for files containing GtkBuilder UI definitions.
RELAX NG Compact Syntax
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 function 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 function explictly with the "type-func" attribute. As a special case, GtkBuilder allows to use an object that has been constructed by a Gtk.UI_Manager.Gtk_UI_Manager in another part of the UI definition by specifying the id of the Gtk.UI_Manager.Gtk_UI_Manager in the "constructor" attribute and the name of the object in the "id" attribute.
Objects may 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. GTK+ reserves ids starting and ending with ___ (3 underscores) for its own purposes.
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.RGBA.Parse).
GVariants can be specified in the format understood by Glib.Variant.Parse, and pixbufs can be specified as a filename of an image file to load.
Objects can be referred to by their name and by default refer to objects declared in the local xml fragment and objects exposed via Gtk.Builder.Expose_Object. In general, GtkBuilder allows forward references to objects â declared in the local xml; an object doesn't have to be 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.
It is also possible to bind a property value to another object's property value using the attributes "bind-source" to specify the source object of the binding, "bind-property" to specify the source property and optionally "bind-flags" to specify the binding flags. Internally builder implements this using GBinding objects. For more information see g_object_bind_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 Gtk_Builder_Connect_Func 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 Gtk.Dialog.Gtk_Dialog). This can be achieved by setting the "internal-child" property 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.
# A GtkBuilder UI Definition
<interface>
<object class="GtkDialog" id="dialog1">
<child internal-child="vbox">
<object class="GtkBox" id="vbox1">
<property name="border-width">10</property>
<child internal-child="action_area">
<object class="GtkButtonBox" 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.
Additionally, since 3.10 a special <template> tag has been added to the format allowing one to define a widget class's components. See the [GtkWidget documentation][composite-templates] for details.
function Add_From_File
(Builder : not null access Gtk_Builder_Record;
Filename : UTF8_String;
Error : access Glib.Error.GError) return Guint
Parses a file containing a [GtkBuilder UI definition][BUILDER-UI] and merges it with the current contents of Builder. Most users will probably want to use Gtk.Builder.Gtk_New_From_File. If an error occurs, 0 will be returned and Error will be assigned a Gerror.Gerror from the GTK_BUILDER_ERROR, G_MARKUP_ERROR or G_FILE_ERROR domain. It's not really reasonable to attempt to handle failures of this call. You should not use this function with untrusted files (ie: files that are not part of your application). Broken Gtk.Builder.Gtk_Builder files can easily crash your program, and it's possible that memory was leaked leading up to the reported failure. The only reasonable thing to do when an error is detected is to call g_error. Since: gtk+ 2.12
the name of the file to parse
A positive value on success, 0 if an error occurred
function Add_From_Resource
(Builder : not null access Gtk_Builder_Record;
Resource_Path : UTF8_String;
Error : access Glib.Error.GError) return Guint
Parses a resource file containing a [GtkBuilder UI definition][BUILDER-UI] and merges it with the current contents of Builder. Most users will probably want to use Gtk.Builder.Gtk_New_From_Resource. If an error occurs, 0 will be returned and Error will be assigned a Gerror.Gerror from the GTK_BUILDER_ERROR, G_MARKUP_ERROR or G_RESOURCE_ERROR domain. It's not really reasonable to attempt to handle failures of this call. The only reasonable thing to do when an error is detected is to call g_error. Since: gtk+ 3.4
the path of the resource file to parse
A positive value on success, 0 if an error occurred
function Add_From_String
(Builder : not null access Gtk_Builder_Record;
Buffer : UTF8_String;
Error : access Glib.Error.GError) return Guint
Parses a string containing a [GtkBuilder UI definition][BUILDER-UI] and merges it with the current contents of Builder. Most users will probably want to use Gtk.Builder.Gtk_New_From_String. Upon errors 0 will be returned and Error will be assigned a Gerror.Gerror from the GTK_BUILDER_ERROR, G_MARKUP_ERROR or G_VARIANT_PARSE_ERROR domain. It's not really reasonable to attempt to handle failures of this call. The only reasonable thing to do when an error is detected is to call g_error. Since: gtk+ 2.12
the string to parse
A positive value on success, 0 if an error occurred
function Add_Objects_From_File
(Builder : not null access Gtk_Builder_Record;
Filename : UTF8_String;
Object_Ids : GNAT.Strings.String_List;
Error : access Glib.Error.GError) return Guint
Parses a file containing a [GtkBuilder UI definition][BUILDER-UI] building only the requested objects and merges them with the current contents of Builder. Upon errors 0 will be returned and Error will be assigned a Gerror.Gerror from the GTK_BUILDER_ERROR, G_MARKUP_ERROR or G_FILE_ERROR domain. If you are adding an object that depends on an object that is not its child (for instance a Gtk.Tree_View.Gtk_Tree_View that depends on its Gtk.Tree_Model.Gtk_Tree_Model), you have to explicitly list all of them in Object_Ids. Since: gtk+ 2.14
the name of the file to parse
nul-terminated array of objects to build
A positive value on success, 0 if an error occurred
function Add_Objects_From_Resource
(Builder : not null access Gtk_Builder_Record;
Resource_Path : UTF8_String;
Object_Ids : GNAT.Strings.String_List;
Error : access Glib.Error.GError) return Guint
Parses a resource file containing a [GtkBuilder UI definition][BUILDER-UI] building only the requested objects and merges them with the current contents of Builder. Upon errors 0 will be returned and Error will be assigned a Gerror.Gerror from the GTK_BUILDER_ERROR, G_MARKUP_ERROR or G_RESOURCE_ERROR domain. If you are adding an object that depends on an object that is not its child (for instance a Gtk.Tree_View.Gtk_Tree_View that depends on its Gtk.Tree_Model.Gtk_Tree_Model), you have to explicitly list all of them in Object_Ids. Since: gtk+ 3.4
the path of the resource file to parse
nul-terminated array of objects to build
A positive value on success, 0 if an error occurred
function Add_Objects_From_String
(Builder : not null access Gtk_Builder_Record;
Buffer : UTF8_String;
Length : Gsize;
Object_Ids : GNAT.Strings.String_List;
Error : access Glib.Error.GError) return Guint
Parses a string containing a [GtkBuilder UI definition][BUILDER-UI] building only the requested objects and merges them with the current contents of Builder. Upon errors 0 will be returned and Error will be assigned a Gerror.Gerror from the GTK_BUILDER_ERROR or G_MARKUP_ERROR domain. If you are adding an object that depends on an object that is not its child (for instance a Gtk.Tree_View.Gtk_Tree_View that depends on its Gtk.Tree_Model.Gtk_Tree_Model), you have to explicitly list all of them in Object_Ids. Since: gtk+ 2.14
the string to parse
the length of Buffer (may be -1 if Buffer is nul-terminated)
nul-terminated array of objects to build
A positive value on success, 0 if an error occurred
procedure Connect_Signals
(Builder : not null access Gtk_Builder_Record;
User_Data : System.Address)
This method is a simpler variation of Gtk.Builder.Connect_Signals_Full. It uses symbols explicitly added to Builder with prior calls to gtk_builder_add_callback_symbol. In the case that symbols are not explicitly added; 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 can only be called once, subsequent calls will do nothing. Note that unless gtk_builder_add_callback_symbol is called for all signal callbacks which are referenced by the loaded XML, this function will require that GModule be supported on the platform. If you rely on GModule support to lookup callbacks in the symbol table, the following details should be noted: 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. Since: gtk+ 2.12
user data to pass back with all signals
procedure Connect_Signals_Full
(Builder : not null access Gtk_Builder_Record;
Func : Gtk_Builder_Connect_Func)
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. Since: gtk+ 2.12
the function used to connect the signals
procedure Expose_Object
(Builder : not null access Gtk_Builder_Record;
Name : UTF8_String;
Object : not null access Glib.Object.GObject_Record'Class)
Add Object to the Builder object pool so it can be referenced just like any other object built by builder. Since: gtk+ 3.8
the name of the object exposed to the builder
the object to expose
function Get_Object
(Builder : not null access Gtk_Builder_Record;
Name : UTF8_String) return Glib.Object.GObject
Gets the object named Name. Note that this function does not increment the reference count of the returned object. Since: gtk+ 2.12
name of object to get
the object named Name or null if it could not be found in the object tree.
function Get_Objects
(Builder : not null access Gtk_Builder_Record)
return Glib.Object.Object_List.GSlist
Gets all objects that have been constructed by Builder. Note that this function does not increment the reference counts of the returned objects. Since: gtk+ 2.12
function Get_Translation_Domain
(Builder : not null access Gtk_Builder_Record) return UTF8_String
Gets the translation domain of Builder. Since: gtk+ 2.12
the translation domain. This string is owned by the builder object and must not be modified or freed.
function Get_Type return Glib.GType
function Get_Type_From_Name
(Builder : not null access Gtk_Builder_Record;
Type_Name : UTF8_String) return GType
Looks up a type by name, using the virtual function that Gtk.Builder.Gtk_Builder has for that purpose. This is mainly used when implementing the Gtk.Buildable.Gtk_Buildable interface on a type. Since: gtk+ 2.12
type name to lookup
the GType found for Type_Name or G_TYPE_INVALID if no type was found
type Gtk_Builder is access all Gtk_Builder_Record'Class;
type Gtk_Builder_Connect_Func is access procedure
(Builder : not null access Gtk_Builder_Record'Class;
Object : not null access Glib.Object.GObject_Record'Class;
Signal_Name : Glib.Signal_Name;
Handler_Name : UTF8_String;
Connect_Object : access Glib.Object.GObject_Record'Class;
Flags : Glib.G_Connect_Flags);
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. Note that this function can only be called once, subsequent calls will do nothing. Since: gtk+ 2.12
a Gtk.Builder.Gtk_Builder
object to connect a signal to
name of the signal
name of the handler
a Glib.Object.GObject, if non-null, use g_signal_connect_object
Glib.G_Connect_Flags to use
function Gtk_Builder_New return Gtk_Builder
Creates a new empty builder object. This function is only useful if you intend to make multiple calls to Gtk.Builder.Add_From_File, Gtk.Builder.Add_From_Resource or Gtk.Builder.Add_From_String in order to merge multiple UI descriptions into a single builder. Most users will probably want to use Gtk.Builder.Gtk_New_From_File, Gtk.Builder.Gtk_New_From_Resource or Gtk.Builder.Gtk_New_From_String. Since: gtk+ 2.12
function Gtk_Builder_New_From_File
(Filename : UTF8_String) return Gtk_Builder
Builds the [GtkBuilder UI definition][BUILDER-UI] in the file Filename. If there is an error opening the file or parsing the description then the program will be aborted. You should only ever attempt to parse user interface descriptions that are shipped as part of your program. Since: gtk+ 3.10
filename of user interface description file
function Gtk_Builder_New_From_Resource
(Resource_Path : UTF8_String) return Gtk_Builder
Builds the [GtkBuilder UI definition][BUILDER-UI] at Resource_Path. If there is an error locating the resource or parsing the description, then the program will be aborted. Since: gtk+ 3.10
a Gresource.Gresource resource path
function Gtk_Builder_New_From_String
(String : UTF8_String;
Length : Gssize) return Gtk_Builder
Builds the user interface described by String (in the [GtkBuilder UI definition][BUILDER-UI] format). If String is null-terminated, then Length should be -1. If Length is not -1, then it is the length of String. If there is an error parsing String then the program will be aborted. You should not attempt to parse user interface description from untrusted sources. Since: gtk+ 3.10
a user interface (XML) description
the length of String, or -1
type Gtk_Builder_Record is new GObject_Record with null record;
procedure Gtk_New (Builder : out Gtk_Builder)
Creates a new empty builder object. This function is only useful if you intend to make multiple calls to Gtk.Builder.Add_From_File, Gtk.Builder.Add_From_Resource or Gtk.Builder.Add_From_String in order to merge multiple UI descriptions into a single builder. Most users will probably want to use Gtk.Builder.Gtk_New_From_File, Gtk.Builder.Gtk_New_From_Resource or Gtk.Builder.Gtk_New_From_String. Since: gtk+ 2.12 Initialize does nothing if the object was already created with another call to Initialize* or G_New.
procedure Gtk_New_From_File
(Builder : out Gtk_Builder;
Filename : UTF8_String)
Builds the [GtkBuilder UI definition][BUILDER-UI] in the file Filename. If there is an error opening the file or parsing the description then the program will be aborted. You should only ever attempt to parse user interface descriptions that are shipped as part of your program. Since: gtk+ 3.10 Initialize_From_File does nothing if the object was already created with another call to Initialize* or G_New.
filename of user interface description file
procedure Gtk_New_From_Resource
(Builder : out Gtk_Builder;
Resource_Path : UTF8_String)
Builds the [GtkBuilder UI definition][BUILDER-UI] at Resource_Path. If there is an error locating the resource or parsing the description, then the program will be aborted. Since: gtk+ 3.10 Initialize_From_Resource does nothing if the object was already created with another call to Initialize* or G_New.
a Gresource.Gresource resource path
procedure Gtk_New_From_String
(Builder : out Gtk_Builder;
String : UTF8_String;
Length : Gssize)
Builds the user interface described by String (in the [GtkBuilder UI definition][BUILDER-UI] format). If String is null-terminated, then Length should be -1. If Length is not -1, then it is the length of String. If there is an error parsing String then the program will be aborted. You should not attempt to parse user interface description from untrusted sources. Since: gtk+ 3.10 Initialize_From_String does nothing if the object was already created with another call to Initialize* or G_New.
a user interface (XML) description
the length of String, or -1
procedure Initialize (Builder : not null access Gtk_Builder_Record'Class)
Creates a new empty builder object. This function is only useful if you intend to make multiple calls to Gtk.Builder.Add_From_File, Gtk.Builder.Add_From_Resource or Gtk.Builder.Add_From_String in order to merge multiple UI descriptions into a single builder. Most users will probably want to use Gtk.Builder.Gtk_New_From_File, Gtk.Builder.Gtk_New_From_Resource or Gtk.Builder.Gtk_New_From_String. Since: gtk+ 2.12 Initialize does nothing if the object was already created with another call to Initialize* or G_New.
procedure Initialize_From_File
(Builder : not null access Gtk_Builder_Record'Class;
Filename : UTF8_String)
Builds the [GtkBuilder UI definition][BUILDER-UI] in the file Filename. If there is an error opening the file or parsing the description then the program will be aborted. You should only ever attempt to parse user interface descriptions that are shipped as part of your program. Since: gtk+ 3.10 Initialize_From_File does nothing if the object was already created with another call to Initialize* or G_New.
filename of user interface description file
procedure Initialize_From_Resource
(Builder : not null access Gtk_Builder_Record'Class;
Resource_Path : UTF8_String)
Builds the [GtkBuilder UI definition][BUILDER-UI] at Resource_Path. If there is an error locating the resource or parsing the description, then the program will be aborted. Since: gtk+ 3.10 Initialize_From_Resource does nothing if the object was already created with another call to Initialize* or G_New.
a Gresource.Gresource resource path
procedure Initialize_From_String
(Builder : not null access Gtk_Builder_Record'Class;
String : UTF8_String;
Length : Gssize)
Builds the user interface described by String (in the [GtkBuilder UI definition][BUILDER-UI] format). If String is null-terminated, then Length should be -1. If Length is not -1, then it is the length of String. If there is an error parsing String then the program will be aborted. You should not attempt to parse user interface description from untrusted sources. Since: gtk+ 3.10 Initialize_From_String does nothing if the object was already created with another call to Initialize* or G_New.
a user interface (XML) description
the length of String, or -1
procedure Lookup_Callback_Symbol
(Builder : not null access Gtk_Builder_Record;
Callback_Name : UTF8_String)
Fetches a symbol previously added to Builder with gtk_builder_add_callback_symbols This function is intended for possible use in language bindings or for any case that one might be cusomizing signal connections using Gtk.Builder.Connect_Signals_Full Since: gtk+ 3.10
The name of the callback @return The callback symbol in Builder for Callback_Name, or null
procedure Set_Translation_Domain
(Builder : not null access Gtk_Builder_Record;
Domain : UTF8_String := "")
Sets the translation domain of Builder. See Gtk.Builder.Gtk_Builder:translation-domain. Since: gtk+ 2.12
the translation domain or null
Translation_Domain_Property : constant Glib.Properties.Property_String;
The translation domain used when translating property values that have been marked as translatable in interface descriptions. If the translation domain is null, Gtk.Builder.Gtk_Builder uses gettext, otherwise g_dgettext.
procedure Value_From_String
(Builder : not null access Gtk_Builder_Record;
Pspec : in out Glib.Param_Spec;
String : UTF8_String;
Value : out Glib.Values.GValue;
Success : out Boolean)
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, Gdk.Color.Gdk_Color, Gdk.RGBA.Gdk_RGBA and Gtk.Adjustment.Gtk_Adjustment type values. Support for Gtk.Widget.Gtk_Widget type values is still to come. Upon errors False will be returned and Error will be assigned a Gerror.Gerror from the GTK_BUILDER_ERROR domain. Since: gtk+ 2.12
the Glib.Param_Spec for the property
the string representation of the value
the Glib.Values.GValue to store the result in @return True on success
function Value_From_String_Type
(Builder : not null access Gtk_Builder_Record;
The_Type : GType;
String : UTF8_String;
Value : access Glib.Values.GValue) return Boolean
Like Gtk.Builder.Value_From_String, this function demarshals a value from a string, but takes a GType instead of Glib.Param_Spec. This function calls g_value_init on the Value argument, so it need not be initialised beforehand. Upon errors False will be returned and Error will be assigned a Gerror.Gerror from the GTK_BUILDER_ERROR domain. Since: gtk+ 2.12
the GType of the value
the string representation of the value
the Glib.Values.GValue to store the result in
True on success