gtk2/docs/reference/gtk/migrating-GtkBuilder.sgml

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<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
               "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
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<chapter id="gtk-migrating-GtkBuilder">

  <title>Migrating from libglade to GtkBuilder</title>

  <para>
    Since version 2.12, GTK+ provides #GtkBuilder to construct
    user interfaces from XML descriptions, similar to the functionality
    provided by #GladeXML in the libglade library.
  </para>

  <para>
    A good way to start a migration from libglade to GtkBuilder is
    to run the <link linkend="gtk-builder-convert">gtk-builder-convert</link>
    utility on your glade file, and inspect the resulting output.
    If your code uses the @root parameter of glade_xml_new(), you
    may want to split your glade file into multiple GtkBuilder files
    by using the <option>--root</option> option of
    <application>gtk-builder-convert</application>. Alternatively, you
    can use gtk_builder_add_objects_from_file() to construct only certain
    objects from a GtkBuilder file.
  </para>

  <para>
    Alternatively, you can open the glade file with
    <application>glade3</application> and then save it in GtkBuilder
    format. This is supported by glade3 since version 3.6.
  </para>

  <table pgwide="1" frame="topbot">
    <title>Step-by-step instructions for porting code from libglade to GtkBuilder</title>
    <tgroup cols="2" colsep="0" rowsep="0">
      <thead>
        <row><entry>libglade</entry><entry>GtkBuilder</entry></row>
      </thead>
      <tbody>
        <row>
          <entry><![CDATA[#include <glade/glade.h>]]></entry>
          <entry>not needed</entry>
        </row>
        <row>
          <entry><screen>GladeXML*</screen></entry>
          <entry><screen>GtkBuilder*</screen></entry>
        </row>
        <row>
          <entry><screen>glade_xml_new (FILE, "first_widget", NULL)</screen></entry>
          <entry>
<screen>
GError* error = NULL;
GtkBuilder* builder = gtk_builder_new (<!-- -->);
if (!gtk_builder_add_from_file (builder, FILE, &amp;error))
  {
    g_warning ("Couldn't load builder file: %amp;s", error->message);
    g_error_free (error);
  }
</screen>
          </entry>
        </row>
        <row>
          <entry><screen>glade_xml_get_widget (gxml, “widget_name”)</screen></entry>
          <entry><screen>GTK_WIDGET (gtk_builder_get_object (builder, “widget_name”))</screen></entry>
        </row>
        <row>
          <entry><screen>glade_get_widget_name (widget)</screen></entry>
          <entry><screen>gtk_widget_get_name (widget)</screen></entry>
        </row>
        <row>
          <entry><screen>glade_xml_get_widget_prefix (gxml, “prefix”)</screen></entry>
          <entry>can be emulated by <literal>gtk_builder_get_objects (builder)</literal> together with manual filtering. It returns a GSList* instead of a GList* though.</entry>
        </row>
      </tbody>
    </tgroup>
  </table>

  <para>
    While GtkBuilder strives to be a complete replacement for
    libglade, there are a number of areas where it is currently
    still behind libglade:
    <itemizedlist>

      <listitem><para>
        GtkBuilder supports context information in translatable
        properties in a slightly different way than libglade.
        Intltool does not yet support this; see
        <ulink url="http://bugzilla.gnome.org/show_bug.cgi?id=454894">bug
        454894</ulink> for the current status of intltool support for
        GtkBuilder files. Thankfully, context in translations is a
        rarely used feature, and if you are not using it, intltools
        glade format support works just fine for GtkBuilder files.
      </para></listitem>

      <listitem><para>
        While libglade can often tolerate multiple widgets having the
        same id in a glade file, GtkBuilder will not accept duplicate
        object ids. Both <application>gtk-builder-convert</application>
        and the GtkBuilder parser emit warnings when they see
        duplicate ids.
      </para></listitem>
  </itemizedlist>
  </para>

</chapter>