Builder

A GtkBuilder reads XML descriptions of a user interface and instantiates the described objects.

To create a GtkBuilder from a user interface description, call [ctor@Gtk.Builder.new_from_file], [ctor@Gtk.Builder.new_from_resource] or [ctor@Gtk.Builder.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 [ctor@Gtk.Builder.new] to get an empty builder and populate it by (multiple) calls to [method@Gtk.Builder.add_from_file], [method@Gtk.Builder.add_from_resource] or [method@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 [method@Gtk.Window.destroy] to get rid of them and all the widgets they contain.

The functions [method@Gtk.Builder.get_object] and [method@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 [method@Gtk.Window.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.

GtkBuilder UI Definitions

GtkBuilder parses textual descriptions of user interfaces which are specified in XML format. We refer to these descriptions as “GtkBuilder UI definitions” or just “UI definitions” if the context is clear.

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 [method@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>”. GtkBuilder 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 explicitly with the "type-func" attribute.

Objects may be given a name with the “id” attribute, which allows the application to retrieve them from the builder with [method@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 ___ (three consecutive 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_INPUT_HINT_EMOJI|GTK_INPUT_HINT_LOWERCASE”) and colors (in a format understood by [method@Gdk.RGBA.parse]).

GVariants can be specified in the format understood by g_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 [method@Gtk.Builder.expose_object]. In general, GtkBuilder 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, and optionally, "bind-property" and "bind-flags" to specify the source property and source binding flags respectively. Internally, GtkBuilder implements this using GBinding objects. For more information see g_object_bind_property().

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 content area of a GtkDialog). 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.

Signal handlers and function pointers

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. 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.

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 Unix, this is not necessary; applications should instead be compiled with the -Wl,--export-dynamic CFLAGS, and linked against gmodule-export-2.0.

A GtkBuilder UI Definition

<interface>
<object class="GtkDialog" id="dialog1">
<child internal-child="vbox">
<object class="GtkBox" id="vbox1">
<child internal-child="action_area">
<object class="GtkBox" id="hbuttonbox1">
<child>
<object class="GtkButton" id="ok_button">
<property name="label">gtk-ok</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.

A <template> tag can be used to define a widget class’s components. See the GtkWidget documentation for details.

class Builder : ObjectG {

protected

GtkBuilder* gtkBuilder;

GtkBuilder* getBuilderStruct(bool transferOwnership);

void* getStruct();

this(GtkBuilder* gtkBuilder, bool ownedRef);

ObjectG[] getObjects();

static GType getType();

this();

this(string filename);

bool addFromFile(string filename);

bool addFromResource(string resourcePath);

bool addFromString(string buffer, ptrdiff_t length);

bool addObjectsFromFile(string filename, string[] objectIds);

bool addObjectsFromResource(string resourcePath, string[] objectIds);

bool addObjectsFromString(string buffer, ptrdiff_t length, string[] objectIds);

Closure createClosure(string functionName, GtkBuilderClosureFlags flags, ObjectG object);

void exposeObject(string name, ObjectG object);

bool extendWithTemplate(ObjectG object, GType templateType, string buffer, ptrdiff_t length);

ObjectG getCurrentObject();

ObjectG getObject(string name);

BuilderScopeIF getScope();

string getTranslationDomain();

GType getTypeFromName(string typeName);

void setCurrentObject(ObjectG currentObject);

void setScope(BuilderScopeIF scope_);

void setTranslationDomain(string domain);

bool valueFromString(ParamSpec pspec, string string_, Value value);

bool valueFromStringType(GType type, string string_, Value value);

}

Constructors

this this(GtkBuilder* gtkBuilder, bool ownedRef): Sets our main struct and passes it to the parent class.
this this(): Creates a new empty builder object.
this this(string filename): Parses the UI definition in the file @filename.

Members

Functions

addFromFile bool addFromFile(string filename): Parses a file containing a UI definition and merges it with the current contents of @builder.
addFromResource bool addFromResource(string resourcePath): Parses a resource file containing a UI definition and merges it with the current contents of @builder.
addFromString bool addFromString(string buffer, ptrdiff_t length): Parses a string containing a UI definition and merges it with the current contents of @builder.
addObjectsFromFile bool addObjectsFromFile(string filename, string[] objectIds): Parses a file containing a UI definition building only the requested objects and merges them with the current contents of @builder.
addObjectsFromResource bool addObjectsFromResource(string resourcePath, string[] objectIds): Parses a resource file containing a UI definition, building only the requested objects and merges them with the current contents of @builder.
addObjectsFromString bool addObjectsFromString(string buffer, ptrdiff_t length, string[] objectIds): Parses a string containing a UI definition, building only the requested objects and merges them with the current contents of @builder.
createClosure Closure createClosure(string functionName, GtkBuilderClosureFlags flags, ObjectG object): Creates a closure to invoke the function called @function_name.
exposeObject void exposeObject(string name, ObjectG object): Add @object to the @builder object pool so it can be referenced just like any other object built by builder.
extendWithTemplate bool extendWithTemplate(ObjectG object, GType templateType, string buffer, ptrdiff_t length): Main private entry point for building composite components from template XML.
getBuilderStruct GtkBuilder* getBuilderStruct(bool transferOwnership): Get the main Gtk struct
getCurrentObject ObjectG getCurrentObject(): Gets the current object set via gtk_builder_set_current_object().
getObject ObjectG getObject(string name): Gets the object named @name.
getObjects ObjectG[] getObjects(): Gets all objects that have been constructed by @builder. Note that this function does not increment the reference counts of the returned objects.
getScope BuilderScopeIF getScope(): Gets the scope in use that was set via gtk_builder_set_scope().
getStruct void* getStruct(): the main Gtk struct as a void*
getTranslationDomain string getTranslationDomain(): Gets the translation domain of @builder.
getTypeFromName GType getTypeFromName(string typeName): Looks up a type by name.
setCurrentObject void setCurrentObject(ObjectG currentObject): Sets the current object for the @builder.
setScope void setScope(BuilderScopeIF scope_): Sets the scope the builder should operate in.
setTranslationDomain void setTranslationDomain(string domain): Sets the translation domain of @builder.
valueFromString bool valueFromString(ParamSpec pspec, string string_, Value value): Demarshals a value from a string.
valueFromStringType bool valueFromStringType(GType type, string string_, Value value): Demarshals a value from a string.

Static functions

getType GType getType()

Variables

gtkBuilder GtkBuilder* gtkBuilder;: the main Gtk struct

Inherited Members

From ObjectG

gObject GObject* gObject;: the main Gtk struct
ownedRef bool ownedRef;: Undocumented in source.
getObjectGStruct GObject* getObjectGStruct(bool transferOwnership): Get the main Gtk struct
getStruct void* getStruct(): the main Gtk struct as a void*
isGcRoot bool isGcRoot;: Undocumented in source.
signals DClosure[gulong] signals;: Undocumented in source.
destroyNotify void destroyNotify(ObjectG obj): Undocumented in source. Be warned that the author may not have intended to support it.
toggleNotify void toggleNotify(ObjectG obj, GObject* object, int isLastRef): Undocumented in source. Be warned that the author may not have intended to support it.
~this ~this(): Undocumented in source.
opCast T opCast()
getDObject RT getDObject(U obj, bool ownedRef): Gets a D Object from the objects table of associations.
removeGcRoot void removeGcRoot(): Undocumented in source. Be warned that the author may not have intended to support it.
setProperty void setProperty(string propertyName, T value)
unref deprecated void unref(ObjectG obj): Undocumented in source. Be warned that the author may not have intended to support it.
doref deprecated ObjectG doref(ObjectG obj): Undocumented in source. Be warned that the author may not have intended to support it.
addOnNotify gulong addOnNotify(void delegate(ParamSpec, ObjectG) dlg, string property, ConnectFlags connectFlags): The notify signal is emitted on an object when one of its properties has been changed. Note that getting this signal doesn't guarantee that the value of the property has actually changed, it may also be emitted when the setter for the property is called to reinstate the previous value.
getType GType getType()
compatControl size_t compatControl(size_t what, void* data)
interfaceFindProperty ParamSpec interfaceFindProperty(TypeInterface gIface, string propertyName): Find the #GParamSpec with the given name for an interface. Generally, the interface vtable passed in as @g_iface will be the default vtable from g_type_default_interface_ref(), or, if you know the interface has already been loaded, g_type_default_interface_peek().
interfaceInstallProperty void interfaceInstallProperty(TypeInterface gIface, ParamSpec pspec): Add a property to an interface; this is only useful for interfaces that are added to GObject-derived types. Adding a property to an interface forces all objects classes with that interface to have a compatible property. The compatible property could be a newly created #GParamSpec, but normally g_object_class_override_property() will be used so that the object class only needs to provide an implementation and inherits the property description, default value, bounds, and so forth from the interface property.
interfaceListProperties ParamSpec[] interfaceListProperties(TypeInterface gIface): Lists the properties of an interface.Generally, the interface vtable passed in as @g_iface will be the default vtable from g_type_default_interface_ref(), or, if you know the interface has already been loaded, g_type_default_interface_peek().
addToggleRef void addToggleRef(GToggleNotify notify, void* data): Increases the reference count of the object by one and sets a callback to be called when all other references to the object are dropped, or when this is already the last reference to the object and another reference is established.
addWeakPointer void addWeakPointer(void* weakPointerLocation): Adds a weak reference from weak_pointer to @object to indicate that the pointer located at @weak_pointer_location is only valid during the lifetime of @object. When the @object is finalized, @weak_pointer will be set to %NULL.
bindProperty Binding bindProperty(string sourceProperty, ObjectG target, string targetProperty, GBindingFlags flags): Creates a binding between @source_property on @source and @target_property on @target. Whenever the @source_property is changed the @target_property is updated using the same value. For instance:
bindPropertyFull Binding bindPropertyFull(string sourceProperty, ObjectG target, string targetProperty, GBindingFlags flags, GBindingTransformFunc transformTo, GBindingTransformFunc transformFrom, void* userData, GDestroyNotify notify): Complete version of g_object_bind_property().
bindPropertyWithClosures Binding bindPropertyWithClosures(string sourceProperty, ObjectG target, string targetProperty, GBindingFlags flags, Closure transformTo, Closure transformFrom): Creates a binding between @source_property on @source and @target_property on @target, allowing you to set the transformation functions to be used by the binding.
dupData void* dupData(string key, GDuplicateFunc dupFunc, void* userData): This is a variant of g_object_get_data() which returns a 'duplicate' of the value. @dup_func defines the meaning of 'duplicate' in this context, it could e.g. take a reference on a ref-counted object.
dupQdata void* dupQdata(GQuark quark, GDuplicateFunc dupFunc, void* userData): This is a variant of g_object_get_qdata() which returns a 'duplicate' of the value. @dup_func defines the meaning of 'duplicate' in this context, it could e.g. take a reference on a ref-counted object.
forceFloating void forceFloating(): This function is intended for #GObject implementations to re-enforce a floating[floating-ref] object reference. Doing this is seldom required: all #GInitiallyUnowneds are created with a floating reference which usually just needs to be sunken by calling g_object_ref_sink().
freezeNotify void freezeNotify(): Increases the freeze count on @object. If the freeze count is non-zero, the emission of "notify" signals on @object is stopped. The signals are queued until the freeze count is decreased to zero. Duplicate notifications are squashed so that at most one #GObject::notify signal is emitted for each property modified while the object is frozen.
getData void* getData(string key): Gets a named field from the objects table of associations (see g_object_set_data()).
getProperty void getProperty(string propertyName, Value value): Gets a property of an object.
getQdata void* getQdata(GQuark quark): This function gets back user data pointers stored via g_object_set_qdata().
getValist void getValist(string firstPropertyName, void* varArgs): Gets properties of an object.
getv void getv(string[] names, Value[] values): Gets @n_properties properties for an @object. Obtained properties will be set to @values. All properties must be valid. Warnings will be emitted and undefined behaviour may result if invalid properties are passed in.
isFloating bool isFloating(): Checks whether @object has a floating[floating-ref] reference.
notify void notify(string propertyName): Emits a "notify" signal for the property @property_name on @object.
notifyByPspec void notifyByPspec(ParamSpec pspec): Emits a "notify" signal for the property specified by @pspec on @object.
doref alias doref = ref_: Undocumented in source.
ref_ ObjectG ref_(): Increases the reference count of @object.
refSink ObjectG refSink(): Increase the reference count of @object, and possibly remove the floating[floating-ref] reference, if @object has a floating reference.
removeToggleRef void removeToggleRef(GToggleNotify notify, void* data): Removes a reference added with g_object_add_toggle_ref(). The reference count of the object is decreased by one.
removeWeakPointer void removeWeakPointer(void* weakPointerLocation): Removes a weak reference from @object that was previously added using g_object_add_weak_pointer(). The @weak_pointer_location has to match the one used with g_object_add_weak_pointer().
replaceData bool replaceData(string key, void* oldval, void* newval, GDestroyNotify destroy, GDestroyNotify oldDestroy): Compares the user data for the key @key on @object with @oldval, and if they are the same, replaces @oldval with @newval.
replaceQdata bool replaceQdata(GQuark quark, void* oldval, void* newval, GDestroyNotify destroy, GDestroyNotify oldDestroy): Compares the user data for the key @quark on @object with @oldval, and if they are the same, replaces @oldval with @newval.
runDispose void runDispose(): Releases all references to other objects. This can be used to break reference cycles.
setData void setData(string key, void* data): Each object carries around a table of associations from strings to pointers. This function lets you set an association.
setDataFull void setDataFull(string key, void* data, GDestroyNotify destroy): Like g_object_set_data() except it adds notification for when the association is destroyed, either by setting it to a different value or when the object is destroyed.
setProperty void setProperty(string propertyName, Value value): Sets a property on an object.
setQdata void setQdata(GQuark quark, void* data): This sets an opaque, named pointer on an object. The name is specified through a #GQuark (retrieved e.g. via g_quark_from_static_string()), and the pointer can be gotten back from the @object with g_object_get_qdata() until the @object is finalized. Setting a previously set user data pointer, overrides (frees) the old pointer set, using #NULL as pointer essentially removes the data stored.
setQdataFull void setQdataFull(GQuark quark, void* data, GDestroyNotify destroy): This function works like g_object_set_qdata(), but in addition, a void (*destroy) (gpointer) function may be specified which is called with @data as argument when the @object is finalized, or the data is being overwritten by a call to g_object_set_qdata() with the same @quark.
setValist void setValist(string firstPropertyName, void* varArgs): Sets properties on an object.
setv void setv(string[] names, Value[] values): Sets @n_properties properties for an @object. Properties to be set will be taken from @values. All properties must be valid. Warnings will be emitted and undefined behaviour may result if invalid properties are passed in.
stealData void* stealData(string key): Remove a specified datum from the object's data associations, without invoking the association's destroy handler.
stealQdata void* stealQdata(GQuark quark): This function gets back user data pointers stored via g_object_set_qdata() and removes the @data from object without invoking its destroy() function (if any was set). Usually, calling this function is only required to update user data pointers with a destroy notifier, for example: |[ void object_add_to_user_list (GObject *object, const gchar *new_string) { // the quark, naming the object data GQuark quark_string_list = g_quark_from_static_string ("my-string-list"); // retrieve the old string list GList *list = g_object_steal_qdata (object, quark_string_list);
thawNotify void thawNotify(): Reverts the effect of a previous call to g_object_freeze_notify(). The freeze count is decreased on @object and when it reaches zero, queued "notify" signals are emitted.
unref void unref(): Decreases the reference count of @object. When its reference count drops to 0, the object is finalized (i.e. its memory is freed).
watchClosure void watchClosure(Closure closure): This function essentially limits the life time of the @closure to the life time of the object. That is, when the object is finalized, the @closure is invalidated by calling g_closure_invalidate() on it, in order to prevent invocations of the closure with a finalized (nonexisting) object. Also, g_object_ref() and g_object_unref() are added as marshal guards to the @closure, to ensure that an extra reference count is held on @object during invocation of the @closure. Usually, this function will be called on closures that use this @object as closure data.
weakRef void weakRef(GWeakNotify notify, void* data): Adds a weak reference callback to an object. Weak references are used for notification when an object is disposed. They are called "weak references" because they allow you to safely hold a pointer to an object without calling g_object_ref() (g_object_ref() adds a strong reference, that is, forces the object to stay alive).
weakUnref void weakUnref(GWeakNotify notify, void* data): Removes a weak reference callback to an object.
clearObject void clearObject(ObjectG objectPtr): Clears a reference to a #GObject.