BuilderProtocol

public protocol BuilderProtocol : ObjectProtocol

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

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

The functions [methodGtk.Builder.get_object] and [methodGtk.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 [methodGtk.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 [methodGtk.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 [methodGtk.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 [methodGdk.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 [methodGtk.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="content_area">
      <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" translatable="yes">_Ok</property>
                <property name="use-underline">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.

A &lt;template&gt; tag can be used to define a widget class’s components. See the GtkWidget documentation for details.

The BuilderProtocol protocol exposes the methods and properties of an underlying GtkBuilder instance. The default implementation of these can be found in the protocol extension below. For a concrete class that implements these methods and properties, see Builder. Alternatively, use BuilderRef as a lighweight, unowned reference if you already have an instance you just want to use.

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  • ptr

    Untyped pointer to the underlying GtkBuilder instance.

    Declaration

    Swift

    var ptr: UnsafeMutableRawPointer! { get }
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  • builder_ptr Default implementation

    Typed pointer to the underlying GtkBuilder instance.

    Default Implementation

    Return the stored, untyped pointer as a typed pointer to the GtkBuilder instance.

    Declaration

    Swift

    var builder_ptr: UnsafeMutablePointer<GtkBuilder>! { get }
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  • Required Initialiser for types conforming to BuilderProtocol

    Declaration

    Swift

    init(raw: UnsafeMutableRawPointer)
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Builder Class

  • Bind a BuilderPropertyName source property to a given target object.

    Declaration

    Swift

    @discardableResult
@inlinable
func bind<Q, T>(property source_property: BuilderPropertyName, to target: T, _ target_property: Q, flags f: BindingFlags = .default, transformFrom transform_from: @escaping GLibObject.ValueTransformer = { $0.transform(destValue: $1) }, transformTo transform_to: @escaping GLibObject.ValueTransformer = { $0.transform(destValue: $1) }) -> BindingRef! where Q : PropertyNameProtocol, T : ObjectProtocol

    Parameters

    source_property

    the source property to bind
    target

    the target object to bind to
    target_property

    the target property to bind to
    flags

    the flags to pass to the Binding
    transform_from

    ValueTransformer to use for forward transformation
    transform_to

    ValueTransformer to use for backwards transformation

    Return Value

    binding reference or nil in case of an error

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  • get(property:) Extension method

    Get the value of a Builder property

    Declaration

    Swift

    @inlinable
func get(property: BuilderPropertyName) -> GLibObject.Value

    Parameters

    property

    the property to get the value for

    Return Value

    the value of the named property

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  • set(property:value:) Extension method

    Set the value of a Builder property. Note that this will only have an effect on properties that are writable and not construct-only!

    Declaration

    Swift

    @inlinable
func set(property: BuilderPropertyName, value v: GLibObject.Value)

    Parameters

    property

    the property to get the value for

    Return Value

    the value of the named property

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Builder Class: BuilderProtocol extension (methods and fields)

  • addFromFile(filename:) Extension method

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

    This function is useful if you need to call [methodGtk.Builder.set_current_object]) to add user data to callbacks before loading GtkBuilder UI. Otherwise, you probably want [ctorGtk.Builder.new_from_file] instead.

    If an error occurs, 0 will be returned and error will be assigned a GError from the GTK_BUILDER_ERROR, G_MARKUP_ERROR or G_FILE_ERROR domains.

    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 GtkBuilder 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().

    Declaration

    Swift

    @inlinable
func addFromFile(filename: UnsafePointer<CChar>!) throws -> Bool
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  • Parses a resource file containing a UI definition and merges it with the current contents of builder.

    This function is useful if you need to call [methodGtk.Builder.set_current_object] to add user data to callbacks before loading GtkBuilder UI. Otherwise, you probably want [ctorGtk.Builder.new_from_resource] instead.

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

    Declaration

    Swift

    @inlinable
func addFromResource(resourcePath: UnsafePointer<CChar>!) throws -> Bool
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  • Parses a string containing a UI definition and merges it with the current contents of builder.

    This function is useful if you need to call [methodGtk.Builder.set_current_object] to add user data to callbacks before loading GtkBuilder UI. Otherwise, you probably want [ctorGtk.Builder.new_from_string] instead.

    Upon errors false will be returned and error will be assigned a 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().

    Declaration

    Swift

    @inlinable
func addFromString(buffer: UnsafePointer<CChar>!, length: gssize) throws -> Bool
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  • Parses a file containing a UI definition 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 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 GtkTreeView that depends on its GtkTreeModel), you have to explicitly list all of them in object_ids.

    Declaration

    Swift

    @inlinable
func addObjectsFromFile(filename: UnsafePointer<CChar>!, objectIds: UnsafeMutablePointer<UnsafePointer<CChar>?>!) throws -> Bool
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  • Parses a resource file containing a UI definition, 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 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 GtkTreeView that depends on its GtkTreeModel), you have to explicitly list all of them in object_ids.

    Declaration

    Swift

    @inlinable
func addObjectsFromResource(resourcePath: UnsafePointer<CChar>!, objectIds: UnsafeMutablePointer<UnsafePointer<CChar>?>!) throws -> Bool
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  • Parses a string containing a UI definition, building only the requested objects and merges them with the current contents of builder.

    Upon errors false will be returned and error will be assigned a 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 GtkTreeView that depends on its GtkTreeModel), you have to explicitly list all of them in object_ids.

    Declaration

    Swift

    @inlinable
func addObjectsFromString(buffer: UnsafePointer<CChar>!, length: gssize, objectIds: UnsafeMutablePointer<UnsafePointer<CChar>?>!) throws -> Bool
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  • Creates a closure to invoke the function called function_name.

    This is using the create_closure() implementation of builder‘s [classGtk.BuilderScope].

    If no closure could be created, nil will be returned and error will be set.

    Declaration

    Swift

    @inlinable
func createClosure(functionName: UnsafePointer<CChar>!, flags: BuilderClosureFlags, object: GLibObject.ObjectRef? = nil) throws -> GLibObject.ClosureRef!
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  • Creates a closure to invoke the function called function_name.

    This is using the create_closure() implementation of builder‘s [classGtk.BuilderScope].

    If no closure could be created, nil will be returned and error will be set.

    Declaration

    Swift

    @inlinable
func createClosure<ObjectT>(functionName: UnsafePointer<CChar>!, flags: BuilderClosureFlags, object: ObjectT?) throws -> GLibObject.ClosureRef! where ObjectT : ObjectProtocol
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  • exposeObject(name:object:) Extension method

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

    Declaration

    Swift

    @inlinable
func exposeObject<ObjectT>(name: UnsafePointer<CChar>!, object: ObjectT) where ObjectT : ObjectProtocol
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  • Main private entry point for building composite components from template XML.

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

    Declaration

    Swift

    @inlinable
func extendWithTemplate<ObjectT>(object: ObjectT, templateType: GType, buffer: UnsafePointer<CChar>!, length: gssize) throws -> Bool where ObjectT : ObjectProtocol
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  • getCurrentObject() Extension method

    Gets the current object set via gtk_builder_set_current_object().

    Declaration

    Swift

    @inlinable
func getCurrentObject() -> GLibObject.ObjectRef!
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  • getObject(name:) Extension method

    Gets the object named name.

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

    Declaration

    Swift

    @inlinable
func getObject(name: UnsafePointer<CChar>!) -> GLibObject.ObjectRef!
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  • getObjects() Extension method

    Gets all objects that have been constructed by builder.

    Note that this function does not increment the reference counts of the returned objects.

    Declaration

    Swift

    @inlinable
func getObjects() -> GLib.SListRef!
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  • getScope() Extension method

    Gets the scope in use that was set via gtk_builder_set_scope().

    Declaration

    Swift

    @inlinable
func getScope() -> BuilderScopeRef!
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  • getTranslationDomain() Extension method

    Gets the translation domain of builder.

    Declaration

    Swift

    @inlinable
func getTranslationDomain() -> String!
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  • getTypeFromName(typeName:) Extension method

    Looks up a type by name.

    This is using the virtual function that GtkBuilder has for that purpose. This is mainly used when implementing the GtkBuildable interface on a type.

    Declaration

    Swift

    @inlinable
func getTypeFromName(typeName: UnsafePointer<CChar>!) -> GType
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  • set(currentObject:) Extension method

    Sets the current object for the builder.

    The current object can be thought of as the this object that the builder is working for and will often be used as the default object when an object is optional.

    [methodGtk.Widget.init_template] for example will set the current object to the widget the template is inited for. For functions like [ctorGtk.Builder.new_from_resource], the current object will be nil.

    Declaration

    Swift

    @inlinable
func set(currentObject: GLibObject.ObjectRef? = nil)
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  • set(currentObject:) Extension method

    Sets the current object for the builder.

    The current object can be thought of as the this object that the builder is working for and will often be used as the default object when an object is optional.

    [methodGtk.Widget.init_template] for example will set the current object to the widget the template is inited for. For functions like [ctorGtk.Builder.new_from_resource], the current object will be nil.

    Declaration

    Swift

    @inlinable
func set<ObjectT>(currentObject: ObjectT?) where ObjectT : ObjectProtocol
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  • set(scope:) Extension method

    Sets the scope the builder should operate in.

    If scope is nil, a new [classGtk.BuilderCScope] will be created.

    Declaration

    Swift

    @inlinable
func set(scope: BuilderScopeRef? = nil)
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  • set(scope:) Extension method

    Sets the scope the builder should operate in.

    If scope is nil, a new [classGtk.BuilderCScope] will be created.

    Declaration

    Swift

    @inlinable
func set<BuilderScopeT>(scope: BuilderScopeT?) where BuilderScopeT : BuilderScopeProtocol
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  • setTranslation(domain:) Extension method

    Sets the translation domain of builder.

    Declaration

    Swift

    @inlinable
func setTranslation(domain: UnsafePointer<CChar>? = nil)
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  • Demarshals a value from a string.

    This function calls g_value_init() on the value argument, so it need not be initialised beforehand.

    Can handle char, uchar, boolean, int, uint, long, ulong, enum, flags, float, double, string, GdkRGBA and GtkAdjustment type values.

    Upon errors false will be returned and error will be assigned a GError from the GTK_BUILDER_ERROR domain.

    Declaration

    Swift

    @inlinable
func valueFromString<ParamSpecT, ValueT>(pspec: ParamSpecT, string: UnsafePointer<CChar>!, value: ValueT) throws -> Bool where ParamSpecT : ParamSpecProtocol, ValueT : ValueProtocol
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  • Demarshals a value from a string.

    Unlike [methodGtk.Builder.value_from_string], this function takes a GType instead of GParamSpec.

    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 from the GTK_BUILDER_ERROR domain.

    Declaration

    Swift

    @inlinable
func valueFromString<ValueT>(type: GType, string: UnsafePointer<CChar>!, value: ValueT) throws -> Bool where ValueT : ValueProtocol
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  • currentObject Extension method

    Gets the current object set via gtk_builder_set_current_object().

    Declaration

    Swift

    @inlinable
var currentObject: GLibObject.ObjectRef! { get nonmutating set }
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  • objects Extension method

    Gets all objects that have been constructed by builder.

    Note that this function does not increment the reference counts of the returned objects.

    Declaration

    Swift

    @inlinable
var objects: GLib.SListRef! { get }
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  • scope Extension method

    The scope the builder is operating in

    Declaration

    Swift

    @inlinable
var scope: BuilderScopeRef! { get nonmutating set }
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  • translationDomain Extension method

    Gets the translation domain of builder.

    Declaration

    Swift

    @inlinable
var translationDomain: String! { get nonmutating set }
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