Gtk.Builder¶

Subclasses:	None

Methods¶

Inherited:	GObject.Object (37)
Structs:	GObject.ObjectClass (5)

class	`new` ()
class	`new_from_file` (filename)
class	`new_from_resource` (resource_path)
class	`new_from_string` (string, length)
	`add_callback_symbol` (callback_name, callback_symbol)
	`add_from_file` (filename)
	`add_from_resource` (resource_path)
	`add_from_string` (buffer, length=-1)
	`add_objects_from_file` (filename, object_ids)
	`add_objects_from_resource` (resource_path, object_ids)
	`add_objects_from_string` (buffer, object_ids)
	`connect_signals` (self, obj_or_map)
	`connect_signals_full` (func, *user_data)
	`expose_object` (name, object)
	`extend_with_template` (widget, template_type, buffer, length)
	`get_application` ()
	`get_object` (name)
	`get_objects` ()
	`get_translation_domain` ()
	`get_type_from_name` (type_name)
	`set_application` (application)
	`set_translation_domain` (domain)
	`value_from_string` (pspec, string)
	`value_from_string_type` (type, string)

Virtual Methods¶

Inherited:	GObject.Object (7)

do_get_type_from_name (type_name)

Properties¶

Name	Type	Flags	Short Description
`translation-domain`	`str`	r/w	The translation domain used by gettext

Signals¶

Inherited:	GObject.Object (1)

Fields¶

Inherited:	GObject.Object (1)

Name	Type	Access	Description
parent_instance	`GObject.Object`	r

Class Details¶

class Gtk.Builder(**kwargs)¶

Bases:	`GObject.Object`
Abstract:	No
Structure:	`Gtk.BuilderClass`

A Gtk.Builder is an auxiliary object that reads textual descriptions of a user interface and instantiates the described objects. To create a Gtk.Builder from a user interface description, call Gtk.Builder.new_from_file(), Gtk.Builder.new_from_resource() or Gtk.Builder.new_from_string().

In the (unusual) case that you want to add user interface descriptions from multiple sources to the same Gtk.Builder you can call Gtk.Builder.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 Gtk.Builder 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 GObject.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.

Gtk.Builder UI Definitions

Gtk.Builder 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 “Gtk.Builder UI definitions” or just “UI definitions” if the context is clear. Do not confuse Gtk.Builder UI Definitions with GtkUIManager UI Definitions, which are more limited in scope. It is common to use .ui as the filename extension for files containing Gtk.Builder 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, Gtk.Builder allows to use an object that has been constructed by a Gtk.UIManager in another part of the UI definition by specifying the id of the Gtk.UIManager 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.

Gtk.Builder 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, Gtk.Builder allows forward references to objects — 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 GObject.Binding objects. For more information see GObject.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 GModule.Module.symbol(), but this can be changed by passing a custom Gtk.BuilderConnectFunc 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). This can be achieved by setting the “internal-child” property of the <child> element to a true value. Note that Gtk.Builder 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 Gtk.Builder 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 for details.

classmethod new()[source]¶

Returns:	a new (empty) `Gtk.Builder` object
Return type:	`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.new_from_file(), Gtk.Builder.new_from_resource() or Gtk.Builder.new_from_string().

New in version 2.12.

classmethod new_from_file(filename)[source]¶

Parameters:	filename (`str`) – filename of user interface description file
Returns:	a `Gtk.Builder` containing the described interface
Return type:	`Gtk.Builder`

Builds the GtkBuilder UI definition 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.

New in version 3.10.

classmethod new_from_resource(resource_path)[source]¶

Parameters:	resource_path (`str`) – a `Gio.Resource` resource path
Returns:	a `Gtk.Builder` containing the described interface
Return type:	`Gtk.Builder`

Builds the GtkBuilder UI definition at resource_path.

If there is an error locating the resource or parsing the description, then the program will be aborted.

New in version 3.10.

classmethod new_from_string(string, length)[source]¶

Parameters:	string (`str`) – a user interface (XML) description length (`int`) – the length of string, or -1
Returns:	a `Gtk.Builder` containing the interface described by string
Return type:	`Gtk.Builder`

Builds the user interface described by string (in the GtkBuilder UI definition format).

If string is None-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.

New in version 3.10.

add_callback_symbol(callback_name, callback_symbol)[source]¶

Parameters:	callback_name (`str`) – The name of the callback, as expected in the XML callback_symbol (`GObject.Callback`) – The callback pointer

Adds the callback_symbol to the scope of self under the given callback_name.

Using this function overrides the behavior of Gtk.Builder.connect_signals() for any callback symbols that are added. Using this method allows for better encapsulation as it does not require that callback symbols be declared in the global namespace.

New in version 3.10.

add_from_file(filename)[source]¶

Parameters:	filename (`str`) – the name of the file to parse
Raises:	`GLib.Error`
Returns:	A positive value on success, 0 if an error occurred
Return type:	`int`

Parses a file containing a GtkBuilder UI definition and merges it with the current contents of self.

Most users will probably want to use Gtk.Builder.new_from_file().

If an error occurs, 0 will be returned and error will be assigned a GLib.Error 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 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().

New in version 2.12.

add_from_resource(resource_path)[source]¶

Parameters:	resource_path (`str`) – the path of the resource file to parse
Raises:	`GLib.Error`
Returns:	A positive value on success, 0 if an error occurred
Return type:	`int`

Parses a resource file containing a GtkBuilder UI definition and merges it with the current contents of self.

Most users will probably want to use Gtk.Builder.new_from_resource().

If an error occurs, 0 will be returned and error will be assigned a GLib.Error 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().

New in version 3.4.

add_from_string(buffer, length=-1)[source]¶

Parameters:	buffer (`str`) – the string to parse length (`int`) – the length of buffer (may be -1 if buffer is nul-terminated)
Raises:	`GLib.Error`
Returns:	A positive value on success, 0 if an error occurred
Return type:	`int`

Parses a string containing a GtkBuilder UI definition and merges it with the current contents of self.

Most users will probably want to use Gtk.Builder.new_from_string().

Upon errors 0 will be returned and error will be assigned a GLib.Error 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().

New in version 2.12.

add_objects_from_file(filename, object_ids)[source]¶

Parameters:	filename (`str`) – the name of the file to parse object_ids ([`str`]) – nul-terminated array of objects to build
Raises:	`GLib.Error`
Returns:	A positive value on success, 0 if an error occurred
Return type:	`int`

Parses a file containing a GtkBuilder UI definition building only the requested objects and merges them with the current contents of self.

Upon errors 0 will be returned and error will be assigned a GLib.Error 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.TreeView that depends on its Gtk.TreeModel), you have to explicitly list all of them in object_ids.

New in version 2.14.

add_objects_from_resource(resource_path, object_ids)[source]¶

Parameters:	resource_path (`str`) – the path of the resource file to parse object_ids ([`str`]) – nul-terminated array of objects to build
Raises:	`GLib.Error`
Returns:	A positive value on success, 0 if an error occurred
Return type:	`int`

Parses a resource file containing a GtkBuilder UI definition building only the requested objects and merges them with the current contents of self.

Upon errors 0 will be returned and error will be assigned a GLib.Error 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.TreeView that depends on its Gtk.TreeModel), you have to explicitly list all of them in object_ids.

New in version 3.4.

add_objects_from_string(buffer, object_ids)[source]¶

Parameters:	buffer (`str`) – the string to parse object_ids ([`str`]) – array of objects to build
Raises:	`GLib.Error`
Returns:	A positive value on success, 0 if an error occurred
Return type:	`int`

Parses a string containing a GtkBuilder UI definition building only the requested objects and merges them with the current contents of self.

Upon errors 0 will be returned and error will be assigned a GLib.Error 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.TreeView that depends on its Gtk.TreeModel), you have to explicitly list all of them in object_ids.

New in version 2.14.

connect_signals(self, obj_or_map)[source]¶

Connect signals specified by this builder to a name, handler mapping.

Connect signal, name, and handler sets specified in the builder with the given mapping “obj_or_map”. The handler/value aspect of the mapping can also contain a tuple in the form of (handler [,arg1 [,argN]]) allowing for extra arguments to be passed to the handler. For example:

builder.connect_signals({'on_clicked': (on_clicked, arg1, arg2)})

New in version 2.12.

connect_signals_full(func, *user_data)[source]¶

Parameters:	func (`Gtk.BuilderConnectFunc`) – the function used to connect the signals user_data (`object` or `None`) – arbitrary data that will be passed to the connection function

This function can be thought of the interpreted language binding version of Gtk.Builder.connect_signals(), except that it does not require GModule.Module to function correctly.

New in version 2.12.

expose_object(name, object)[source]¶

Parameters:	name (`str`) – the name of the object exposed to the builder object (`GObject.Object`) – the object to expose

Add object to the self object pool so it can be referenced just like any other object built by builder.

New in version 3.8.

extend_with_template(widget, template_type, buffer, length)[source]¶

Parameters:	widget (`Gtk.Widget`) – the widget that is being extended template_type (`GObject.GType`) – the type that the template is for buffer (`str`) – the string to parse length (`int`) – the length of buffer (may be -1 if buffer is nul-terminated)
Raises:	`GLib.Error`
Returns:	A positive value on success, 0 if an error occurred
Return type:	`int`

Main private entry point for building composite container components from template XML.

This is exported purely to let gtk-builder-tool validate templates, applications have no need to call this function.

get_application()[source]¶

Returns:	the application being used by the builder, or `None`
Return type:	`Gtk.Application` or `None`

Gets the Gtk.Application associated with the builder.

The Gtk.Application is used for creating action proxies as requested from XML that the builder is loading.

By default, the builder uses the default application: the one from Gio.Application.get_default(). If you want to use another application for constructing proxies, use Gtk.Builder.set_application().

New in version 3.10.

get_object(name)[source]¶

Parameters:	name (`str`) – name of object to get
Returns:	the object named name or `None` if it could not be found in the object tree.
Return type:	`GObject.Object` or `None`

Gets the object named name. Note that this function does not increment the reference count of the returned object.

New in version 2.12.

get_objects()[source]¶

Returns:	a newly-allocated `GLib.SList` containing all the objects constructed by the `Gtk.Builder` instance. It should be freed by g_slist_free()
Return type:	[`GObject.Object`]

Gets all objects that have been constructed by self. Note that this function does not increment the reference counts of the returned objects.

New in version 2.12.

get_translation_domain()[source]¶

Returns:	the translation domain. This string is owned by the builder object and must not be modified or freed.
Return type:	`str`

Gets the translation domain of self.

New in version 2.12.

get_type_from_name(type_name)[source]¶

Parameters:	type_name (`str`) – type name to lookup
Returns:	the `GObject.GType` found for type_name or `GObject.TYPE_INVALID` if no type was found
Return type:	`GObject.GType`

Looks up a type by name, using the virtual function that Gtk.Builder has for that purpose. This is mainly used when implementing the Gtk.Buildable interface on a type.

New in version 2.12.

set_application(application)[source]¶

Parameters:	application (`Gtk.Application`) – a `Gtk.Application`

Sets the application associated with self.

You only need this function if there is more than one Gio.Application in your process. application cannot be None.

New in version 3.10.

set_translation_domain(domain)[source]¶

Parameters:	domain (`str` or `None`) – the translation domain or `None`

Sets the translation domain of self. See Gtk.Builder :translation-domain.

New in version 2.12.

value_from_string(pspec, string)[source]¶

Parameters:

pspec (GObject.ParamSpec) – the GObject.ParamSpec for the property
string (str) – the string representation of the value

Raises:

GLib.Error

Returns:

True on success

value:	the `GObject.Value` to store the result in

Return type:

(bool, value: GObject.Value)

This function demarshals a value from a string. This function calls GObject.Value.init() on the value argument, so it need not be initialised beforehand.

This function can handle str, uchar, boolean, int, uint, long, ulong, enum, flags, float, double, string, Gdk.Color, Gdk.RGBA and Gtk.Adjustment type values. Support for Gtk.Widget type values is still to come.

Upon errors False will be returned and error will be assigned a GLib.Error from the #GTK_BUILDER_ERROR domain.

New in version 2.12.

value_from_string_type(type, string)[source]¶

Parameters:

type (GObject.GType) – the GObject.GType of the value
string (str) – the string representation of the value

Raises:

GLib.Error

Returns:

True on success

value:	the `GObject.Value` to store the result in

Return type:

(bool, value: GObject.Value)

Like Gtk.Builder.value_from_string(), this function demarshals a value from a string, but takes a GObject.GType instead of GObject.ParamSpec. This function calls GObject.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 GLib.Error from the #GTK_BUILDER_ERROR domain.

New in version 2.12.

do_get_type_from_name(type_name) virtual¶

Parameters:	type_name (`str`) – type name to lookup
Returns:	the `GObject.GType` found for type_name or `GObject.TYPE_INVALID` if no type was found
Return type:	`GObject.GType`

Looks up a type by name, using the virtual function that Gtk.Builder has for that purpose. This is mainly used when implementing the Gtk.Buildable interface on a type.

New in version 2.12.

Property Details¶

Gtk.Builder.props.translation_domain¶

Name:	`translation-domain`
Type:	`str`
Default Value:	`None`
Flags:	`READABLE`, `WRITABLE`

The translation domain used when translating property values that have been marked as translatable in interface descriptions. If the translation domain is None, Gtk.Builder uses gettext(), otherwise GLib.dgettext().

New in version 2.12.