builder.ui and spinbutton adjustment

[Roger Matthews <roger matthews hotmail com>]

Problem: spinbutton adjustment “value” not displayed on otherwise functional floating-point and integer 
spinbuttons, built from builder.ui, using C language on Ubuntu 14.04, with Gtk+ 3.0. I have already built a 
gui coded in C without using a builder.ui file and am now attempting to reproduce this with a builder.ui to 
make the application. The interface opens, the 'hello' and 'quit' buttons work, the spinbuttons are active, 
can be changed and printed to the terminal via the callback functions, but the initial “value” is either 0.0 
or 0 for float and integer respectively, and not the intended initial value. The two run-time messages shown 
immediately below obviously refer to the two spinbutton adjustments. Sorry about the length of this email, if 
the code below is copied to your computer it should run, thanks,
Roger Matthews.

Written at terminal:---------------------------------------------------

/Roger_app2$ gedit spin_app.c
/Roger_app2$ make
/Roger_app2$ ./spin_app
(spin_app:3326): Gtk-CRITICAL **: gtk_buildable_add_child: assertion 'iface->add_child != NULL' failed
(spin_app:3326): Gtk-CRITICAL **: gtk_buildable_add_child: assertion 'iface->add_child != NULL' failed
float1 = 0.1
float1 = 0.2
float1 = 0.3
integer1 = 1
integer1 = 2
integer1 = 3
integer1 = 4
Hello World
/Roger_app2$

spin_app.c -----------------------------------------------------------------
compiled with:
gcc `pkg-config --cflags gtk+-3.0` -o spin_app spin_app.c `pkg-config --libs gtk+-3.0`

#include <stdio.h>
#include <gtk/gtk.h>

float float1 = 53.1;
int integer1 = 53;

static void
print_hello (GtkWidget *widget,
             gpointer   data)
{
  g_print ("Hello World\n");
}

static void get_new_number_float_float1(GtkWidget *widget, gpointer data)
{
float1 = gtk_spin_button_get_value(GTK_SPIN_BUTTON(widget));
printf("float1 = %.1f\n", float1);
}

static void get_new_number_int_integer1(GtkWidget *widget, gpointer data)
{
integer1 = gtk_spin_button_get_value_as_int(GTK_SPIN_BUTTON(widget));
printf("integer1 = %d\n", integer1);
}

static void do_drawing(cairo_t *, GtkWidget *);

static gboolean on_draw_event(GtkWidget *widget, cairo_t *cr,
    gpointer user_data)
{
  do_drawing(cr, widget);
  return FALSE;
}

static void do_drawing(cairo_t *cr, GtkWidget *widget)
{
  GtkWidget *win = gtk_widget_get_toplevel(widget);

  int winwidth_draw1, winheight_draw1;
  gtk_window_get_size(GTK_WINDOW(win), &winwidth_draw1, &winheight_draw1);
  cairo_set_source_rgb(cr, 0.6, 0.0, 0.0);
  cairo_set_line_width(cr, 1.0);
  cairo_move_to(cr, 20, 20);
  cairo_line_to(cr, 70, 135);
  cairo_stroke(cr);
}

int
main (int   argc,
      char *argv[])
{
  GtkBuilder *builder;
  GObject *window;
  GObject *notebook;
  GObject *label1;
  GObject *spin_float1;
  GObject *label2;
  GObject *spin_int1;
  GObject *notebook_tab1;
  GObject *button_hello;
  GObject *notebook_tab2;
  GObject *button_quit;
  GObject *notebook_tab3;
  GObject *adjustment1;
  GObject *adjustment2;

  gtk_init (&argc, &argv);

  /* Construct a GtkBuilder instance and load our UI description */
  builder = gtk_builder_new ();
  gtk_builder_add_from_file (builder, "builder.ui", NULL);

  /* Connect signal handlers to the constructed widgets. */
  window = gtk_builder_get_object (builder, "window");
  g_signal_connect (window, "destroy", G_CALLBACK (gtk_main_quit), NULL);

  spin_float1 = gtk_builder_get_object (builder, "button1");
  g_signal_connect (spin_float1, "value-changed",
                    G_CALLBACK (get_new_number_float_float1), NULL);

  spin_int1 = gtk_builder_get_object (builder, "button2");
  g_signal_connect (spin_int1, "value-changed",
                    G_CALLBACK (get_new_number_int_integer1), NULL);

  button_hello = gtk_builder_get_object (builder, "button_hello");
  g_signal_connect (button_hello, "clicked", G_CALLBACK (print_hello), NULL);

  button_quit = gtk_builder_get_object (builder, "quit");
  g_signal_connect (button_quit, "clicked", G_CALLBACK (gtk_main_quit), NULL);

  gtk_main ();

  return 0;
}

builder.ui --------------------------------------------------------------------------------

<?xml version="1.0" encoding="UTF-8"?>
<interface>
  <object id="window" class="GtkWindow">
    <property name="visible">True</property>
    <property name="title">Roger's App</property>
    <property name="border-width">10</property>
    <property name="default-width">600</property>
    <property name="default-height">400</property>
    <child>
      <object id="notebook" class="GtkNotebook">
        <property name="visible">True</property>
        <property name="can_focus">True</property>

            <child>
              <object class="GtkLayout" id="content_layout">
                <property name="visible">True</property>
                <property name="width">1200</property>
                <property name="height">1200</property>
                  <child>
                    <object class="GtkLabel" id="label1">
                      <property name="label">Label1</property>
                      <property name="visible">True</property>
                    </object>
                      <packing>
                      <property name="x">1</property>
                      <property name="y">1</property>
                      </packing>
                  </child>
                  <child>
                    <object id="button1" class="GtkSpinButton">
                      <property name="visible">True</property>
                      <property name="numeric">True</property>
                      <property name="snap-to-ticks">True</property>
                      <!--<property name="value">53.1</property> -->
                      <property name="climb-rate">1</property>
                      <property name="digits">1</property>
                      <property name="adjustment">adjustment1</property>
                      <child>
                        <object id="adjustment1" class="GtkAdjustment">
                          <property name="value">53.1</property>
                          <property name="lower">0.0</property>
                          <property name="upper">112.0</property>
                          <property name="step-increment">0.1</property>
                          <property name="page-increment">1</property>
                          <property name="page-size">1</property>
                        </object>
                      </child>
                    </object>
                    <packing>
                      <property name="x">1</property>
                      <property name="y">20</property>
                    </packing>
                  </child>
                  <child>
                    <object class="GtkLabel" id="label2">
                      <property name="label">Label2</property>
                      <property name="visible">True</property>
                    </object>
                      <packing>
                      <property name="x">120</property>
                      <property name="y">1</property>
                      </packing>
                  </child>
                  <child>
                    <object id="button2" class="GtkSpinButton">
                      <property name="visible">True</property>
                      <property name="numeric">True</property>
                      <property name="snap-to-ticks">True</property>
                      <!--<property name="value">53</property> -->
                      <property name="climb-rate">1</property>
                      <property name="digits">0</property>
                      <property name="adjustment">adjustment2</property>
                     <child>
                       <object id="adjustment2" class="GtkAdjustment">
                         <property name="value">53</property>
                         <property name="lower">0</property>
                         <property name="upper">112</property>
                         <property name="step-increment">1</property>
                         <property name="page-increment">1</property>
                         <property name="page-size">1</property>
                       </object>
                     </child>
                    </object>
                    <packing>
                      <property name="x">120</property>
                      <property name="y">20</property>
                    </packing>
                  </child>
              </object>
            </child>

        <child type="tab">
          <object class="GtkLabel" id="notebook_tab1">
            <property name="label">Tab1</property>
          </object>
        </child>
        <child>
          <object id="button_hello" class="GtkButton">
            <property name="visible">True</property>
            <property name="label">Hello</property>
          </object>
          <packing>
          </packing>
        </child>
        <child type="tab">
          <object class="GtkLabel" id="notebook_tab2">
            <property name="label">Tab2</property>
          </object>
        </child>
        <child>
          <object id="quit" class="GtkButton">
            <property name="visible">True</property>
            <property name="label">Quit</property>
          </object>
          <packing>
          </packing>
        </child>
        <child type="tab">
          <object class="GtkLabel" id="notebook_tab3">
            <property name="label">Tab3</property>
          </object>
        </child>
      </object>
    </child>
  </object>
</interface>