Gnome::Gtk3::Builder

Build an interface from an XML UI definition

Description

A Gnome::Gtk3::Builder is an auxiliary object that reads textual descriptions of a user interface and instantiates the described objects. To create a Gnome::Gtk3::Builder from a user interface description, call .new(:file), .new(:resource) or .new(:string).

In the (unusual) case that you want to add user interface descriptions from multiple sources to the same Gnome::Gtk3::Builder you can call .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 Gnome::Gtk3::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 function gtk_builder_get_object() can be used to access the widgets in the interface by the names assigned to them (id’s) 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. All widget classes have the ability to be initialized using the named argument .new(:build-id). This will end up using gtk_builder_get_object(). A builder must be created first and data fed to the builder before you are able to use it.

The function gtk_builder_connect_signals_full() and variants thereof can be used to connect handlers to the named signals defined in a handler table. The signals can also be handled individualy using .register-signal().

Gnome::Gtk3::Builder UI Definitions

Gnome::Gtk3::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 “GtkBuilder UI definitions” or just “UI definitions” if the context is clear.

It is common to use .ui as the filename extension for files containing Gnome::Gtk3::Builder UI definitions.

The toplevel element is . 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

Typically, the specific kind of object represented by an

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() which is also used indirectly when a widget is created using .new(:$build-id). 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 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.

Objects can be referred to by their name and by default refer to objects declared in the local xml fragment and objects exposed via expose_object(). In general, Gnome::Gtk3::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.

Signal handlers are set up with the 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” and “swapped” attributes are ignored by the Raku modules. The "object" field has a meaning in **Gnome::Gtk3::Glade**.

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 Gnome::Gtk3::Dialog). This can be achieved by setting the “internal-child” propery of the element to a true value. Note that **Gnome::Gtk3::Builder** still requires an

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 . The possible values for the “type” attribute are described in the sections describing the widget-specific portions of UI definitions.

A Gnome::Gtk3::Builder UI Definition

Note the class names are e.g. GtkDialog, not Gnome::Gtk3::Dialog. This is because those are the c-source class names of the GTK+ objects.

<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>

To load it and use it do the following (assume above text is in $gui).

my Gnome::Gtk3::Builder $builder .= new(:string($gui));
my Gnome::Gtk3::Button $button .= new(:build-id<ok_button>));

Synopsis

Declaration

unit class Gnome::Gtk3::Builder;
also is Gnome::GObject::Object;

Uml Diagram

Example

my Gnome::Gtk3::Builder $builder .= new;
my Gnome::Glib::Error $e = $builder.add-from-file($ui-file);
die $e.message if $e.is-valid;

my Gnome::Gtk3::Button .= new(:build-id<my-glade-button-id>);

Types

enum GtkBuilderError

Error codes that identify various errors that can occur while using Gnome::Gtk3::Builder.

• GTK_BUILDER_ERROR_INVALID_TYPE_FUNCTION: A type-func attribute didn’t name a function that returns a GType.

• GTK_BUILDER_ERROR_UNHANDLED_TAG: The input contained a tag that Gnome::Gtk3::Builder can’t handle.

• GTK_BUILDER_ERROR_MISSING_ATTRIBUTE: An attribute that is required by Gnome::Gtk3::Builder was missing.

• GTK_BUILDER_ERROR_INVALID_ATTRIBUTE: Gnome::Gtk3::Builder found an attribute that it doesn’t understand.

• GTK_BUILDER_ERROR_INVALID_TAG: Gnome::Gtk3::Builder found a tag that it doesn’t understand.

• GTK_BUILDER_ERROR_MISSING_PROPERTY_VALUE: A required property value was missing.

• GTK_BUILDER_ERROR_INVALID_VALUE: Gnome::Gtk3::Builder couldn’t parse some attribute value.

• GTK_BUILDER_ERROR_VERSION_MISMATCH: The input file requires a newer version of GTK+.

• GTK_BUILDER_ERROR_DUPLICATE_ID: An object id occurred twice.

• GTK_BUILDER_ERROR_OBJECT_TYPE_REFUSED: A specified object type is of the same type or derived from the type of the composite class being extended with builder XML.

• GTK_BUILDER_ERROR_TEMPLATE_MISMATCH: The wrong type was specified in a composite class’s template XML

• GTK_BUILDER_ERROR_INVALID_PROPERTY: The specified property is unknown for the object class.

• GTK_BUILDER_ERROR_INVALID_SIGNAL: The specified signal is unknown for the object class.

• GTK_BUILDER_ERROR_INVALID_ID: An object id is unknown

Methods

new

default, no options

Create an empty builder. This is only useful if you intend to make multiple calls to add-from-file(), add-from-resource() or add-from-string() in order to merge multiple UI descriptions into a single builder.

Most users will probably want to use .new(:file), .new(:resource) or .new(:string), particularly when there is only one file, resource or string.

multi method new ( )

:file

Create builder object and load gui design. Builds the UI definition from a file. 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.

multi method new ( Str :$file! )

:string

Same as above but read the design from the string. Builds the user interface described by $string (in the UI definition format). 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.

multi method new ( Str :$string! )

:resource

The interface is build using the UI definition from the given resource path. If there is an error locating the resource or parsing the description, then the program will be aborted.

multi method new ( Str :$resource! )

:native-object

Create a Builder object using a native object from elsewhere. See also Gnome::N::TopLevelClassSupport.

multi method new ( N-GObject :$native-object! )

add-from-file

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 new-from-file().

If an error occurs, 0 will be returned and error will be assigned a Gnome::Gtk3::Error from the Gnome::Gtk3::TK-BUILDER-ERROR, Gnome::Gtk3::-MARKUP-ERROR or Gnome::Gtk3::-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 Gnome::Gtk3::Builder files can easily crash your program, and it’s possible that memory was leaked leading up to the reported failure.

Returns: An invalid error object on success, Otherwise call .message() on the error object to find out what went wrong.

method add-from-file ( Str $filename --> Gnome::Glib::Error )

• $filename; the name of the file to parse

add-from-resource

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 new-from-resource().

If an error occurs, 0 will be returned and error will be assigned a Gnome::Gtk3::Error from the Gnome::Gtk3::TK-BUILDER-ERROR, Gnome::Gtk3::-MARKUP-ERROR or Gnome::Gtk3::-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().

Returns: An invalid error object on success, Otherwise call .message() on the error object to find out what went wrong.

method add-from-resource ( Str $resource_path --> Gnome::Glib::Error )

• $resource_path; the path of the resource file to parse

add-from-string

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 new-from-string().

Upon errors 0 will be returned and error will be assigned a Gnome::Gtk3::Error from the Gnome::Gtk3::TK-BUILDER-ERROR, Gnome::Gtk3::-MARKUP-ERROR or Gnome::Gtk3::-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().

Returns: An invalid error object on success, Otherwise call .message() on the error object to find out what went wrong.

method add-from-string ( Str $buffer --> Gnome::Glib::Error )

• $buffer; the string to parse

connect-signals-full

This method will process the signal elements from the loaded XML and with the help of the provided $handlers table register each handler to a signal.

method gtk_builder_connect_signals_full ( Hash $handlers )

• $handlers; a table used to register handlers to process a signal. Each entry in this table has a key which is the name of the handler method. The value is a list of which the first element is the object wherin the method is defined. The rest of the list are optional named attributes and are provided to the method. See also register-signal() in Gnome::GObject::Object.

An example where a gui is described in XML. It has a Window with a Button, both having a signal description;

my Str $ui = q:to/EOUI/;
    <?xml version="1.0" encoding="UTF-8"?>
    <interface>
      <requires lib="gtk+" version="3.20"/>

      <object class="GtkWindow" id="top">
        <property name="title">top window</property>
        <signal name="destroy" handler="window-quit"/>
        <child>
          <object class="GtkButton" id="help">
            <property name="label">Help</property>
            <signal name="clicked" handler="button-click"/>
          </object>
        </child>
      </object>
    </interface>
    EOUI

# First handler class
class X {
  method window-quit ( :$o1, :$o2 ) {
    # ... do something with options $o1 and $o2 ...

    Gnome::Gtk3::Main.new.gtk-main-quit;
  }
}

# Second handler class
class Y {
  method button-click ( :$o3, :$o4 ) {
    # ... do something with options $o3 and $o4 ...
  }
}

# Load the user interface description
my Gnome::Gtk3::Builder $builder .= new(:string($ui));
my Gnome::Gtk3::Window $w .= new(:build-id<top>);

# It is possible to devide the works over more than one class
my X $x .= new;
my Y $y .= new;

# Create the handlers table
my Hash $handlers = %(
  :window-quit( $x, :o1<o1>, :o2<o2>),
  :button-click( $y, :o3<o3>, :o4<o4>)
);

# Register all signals
$builder.connect-signals-full($handlers);

error-quark

Return the domain code of the builder error domain.

method error-quark ( --> UInt )

The following example shows the fields of a returned error when a faulty string is provided in the call.

my Gnome::Glib::Quark $quark .= new;
my Gnome::Glib::Error $e = $builder.add-from-string($text);
is $e.domain, $builder.gtk_builder_error_quark(),
   "domain code: $e.domain()";
is $quark.to-string($e.domain), 'gtk-builder-error-quark',
   "error domain: $quark.to-string($e.domain())";

expose-object

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

method expose-object ( Str $name, N-GObject() $object )

• $name; the name of the object exposed to the builder

• $object; the object to expose

get-application

Gets the Gnome::Gtk3::Application associated with the builder.

The Gnome::Gtk3::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 g-application-get-default(). If you want to use another application for constructing proxies, use set-application().

Returns: the application being used by the builder, or undefined

method get-application ( --> N-GObject )

get-object

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

Returns: the object named $name or undefined if it could not be found in the object tree.

method get-object ( Str $name --> N-GObject )

• $name; name of object to get

get-objects

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

Returns: (element-type GObject) (transfer container): a newly-allocated Gnome::Gtk3::SList containing all the objects constructed by the Gnome::Gtk3::Builder instance. It should be freed by g-slist-free()

method get-objects ( --> Gnome::Glib::SList )

get-type-from-name

Looks up a type by name, using the virtual function that Gnome::Gtk3::Builder has for that purpose. This is mainly used when implementing the Gnome::Gtk3::Buildable interface on a type.

Returns: the Gnome::Gtk3::Type found for $type-name or Gnome::Gtk3::-TYPE-INVALID if no type was found

method get-type-from-name ( Str $type-name --> UInt )

• $type_name; type name to lookup

set-application

Sets the application associated with builder.

You only need this function if there is more than one Gnome::Gtk3::Application in your process. $application cannot be undefined.

method set-application ( N-GObject() $application )

• $application; a Gnome::Gtk3::Application

set-translation-domain

Sets the translation domain of builder. See translation-domain.

method set-translation-domain ( Str $domain )

• $domain; the translation domain or undefined

Properties

translation-domain

The translation domain used by gettext

The Gnome::GObject::Value type of property translation-domain is G_TYPE_STRING.

• Parameter is readable and writable.

• Default value is undefined.