auto connect signals

Discussion:

Xiao Yafeng

2009-08-06 03:37:51 UTC

I'm new to glade programming. below is my first gtk+ snippet with glade.
hello.c:

#include <gtk/gtk.h>

static int count;
void on_button_quit_clicked (GtkWidget *button, gpointer userdata){
//gtk_window_resize(window,(gint)100+count,(gint)100+count);
//count = count + 1;
gtk_main_quit();
}

int main (int argc, char **argv){
GtkBuilder *builder;
GtkWidget *window;
GtkWidget *button;
gtk_init (&argc, &argv);
builder = gtk_builder_new();
gtk_builder_add_from_file(builder, "hello.glade", NULL);
gtk_builder_connect_signals(builder,(GtkBuilde,NULL);
gtk_widget_show_all(window);
gtk_main();
return 0;
}

hello.glade:

<?xml version="2.0"?>
<interface>
<requires lib="gtk+" version="2.16"/>

<object class="GtkWindow" id="window1">
<child>
<object class="GtkVPaned" id="vpaned1">
<property name="visible">True</property>
<property name="can_focus">True</property>
<property name="orientation">vertical</property>
<child>
<object class="GtkLabel" id="label1">
<property name="visible">True</property>
<property name="label" translatable="yes">label</property>
</object>
<packing>
<property name="resize">False</property>
<property name="shrink">True</property>
</packing>
</child>
<child>
<object class="GtkHBox" id="hbox1">
<property name="visible">True</property>
<child>
<placeholder/>
</child>
<child>
<object class="GtkHButtonBox" id="hbuttonbox1">
<property name="visible">True</property>
<child>
<object class="GtkButton" id="button_quit">
<property name="label"
translatable="yes">quit</property>
<property name="visible">True</property>
<property name="can_focus">True</property>
<property name="receives_default">True</property>
<signal name="clicked" handler="on_button_quit_clicked"
object="NULL"/>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">False</property>
<property name="position">0</property>
</packing>
</child>
<child>
<object class="GtkButton" id="button2">
<property name="label"
translatable="yes">button</property>
<property name="visible">True</property>
<property name="can_focus">True</property>
<property name="receives_default">True</property>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">False</property>
<property name="position">1</property>
</packing>
</child>
</object>
<packing>
<property name="position">1</property>
</packing>
</child>
<child>
<placeholder/>
</child>
</object>
<packing>
<property name="resize">True</property>
<property name="shrink">True</property>
</packing>
</child>
</object>
</child>
</object>
</interface>

error message:

(hello:8403): Gtk-WARNING **: Could not lookup object NULL on signal clicked
of object button_quit

(hello:8403): Gtk-CRITICAL **: gtk_main_quit: assertion `main_loops != NULL'
failed
Segmentation fault

It seems NULL is cause of failure, but who can post a correct code to prove
my guess?

TIA

Tristan Van Berkom

2009-08-06 04:18:22 UTC

Permalink

Post by Xiao Yafeng
I'm new to glade programming. below is my first gtk+ snippet with glade.

[...]

Post by Xiao Yafeng
(hello:8403): Gtk-WARNING **: Could not lookup object NULL on signal clicked
of object button_quit
(hello:8403): Gtk-CRITICAL **: gtk_main_quit: assertion `main_loops != NULL'
failed
Segmentation fault
It seems NULL is cause of failure, but who can post a correct code to prove
my guess?

The "object" parameter is a string to be set by the user in Glade - I have no
idea how you ended up with the string NULL, it should just be empty if you
dont want to specify an object.

Note also when using the "object" (userdata) field, the specified object will
be swapped with the emitting object and thus come first in the callback`s
argument list (the string specified for "object" is a name of another object
in the same Glade file).

Cheers,
-Tristan
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Xiao Yafeng

2009-08-06 05:59:33 UTC

Permalink

Thanks for reply!
I modify the code as suggested and rerun:
hello.c:
#include <gtk/gtk.h>

void on_button_quit_clicked (GtkWidget *button, gpointer userdata){
gtk_main_quit();
}

int main (int argc, char **argv){
GtkBuilder *builder;
GtkWidget *window;
GtkWidget *button;
gtk_init (&argc, &argv);
builder = gtk_builder_new();
window = GTK_WIDGET(gtk_builder_get_object(builder, "window1"));
gtk_builder_add_from_file(builder, "hello.glade", NULL);
gtk_builder_connect_signals(builder, NULL);
gtk_widget_show_all(window);
gtk_main();
return 0;
}

hello.glade:
<?xml version="1.0"?>
<interface>
<requires lib="gtk+" version="2.16"/>

<object class="GtkWindow" id="window1">
<child>
<object class="GtkVPaned" id="vpaned1">
<property name="visible">True</property>
<property name="can_focus">True</property>
<property name="orientation">vertical</property>
<child>
<object class="GtkLabel" id="label1">
<property name="visible">True</property>
<property name="label" translatable="yes">label</property>
</object>
<packing>
<property name="resize">False</property>
<property name="shrink">True</property>
</packing>
</child>
<child>
<object class="GtkHBox" id="hbox1">
<property name="visible">True</property>
<child>
<placeholder/>
</child>
<child>
<object class="GtkHButtonBox" id="hbuttonbox1">
<property name="visible">True</property>
<child>
<object class="GtkButton" id="button_quit">
<property name="label"
translatable="yes">quit</property>
<property name="visible">True</property>
<property name="can_focus">True</property>
<property name="receives_default">True</property>
<signal name="clicked"
handler="on_button_quit_clicked"/>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">False</property>
<property name="position">0</property>
</packing>
</child>
<child>
<object class="GtkButton" id="button2">
<property name="label"
translatable="yes">button</property>
<property name="visible">True</property>
<property name="can_focus">True</property>
<property name="receives_default">True</property>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">False</property>
<property name="position">1</property>
</packing>
</child>
</object>
<packing>
<property name="position">1</property>
</packing>
</child>
<child>
<placeholder/>
</child>
</object>
<packing>
<property name="resize">True</property>
<property name="shrink">True</property>
</packing>
</child>
</object>
</child>
</object>
</interface>

error messages:
(hello:12512): Gtk-WARNING **: Could not find signal handler
'on_button_quit_clicked'
Segmentation fault

new error message confuse me. It seems I do not pass the callback function
to button widget successfully. I 've tried to connect signals explicit:
first, ERASE signal handler in hello.glade.
hello.c
#include <gtk/gtk.h>

void on_button_quit_clicked (GtkWidget *button, gpointer userdata){
gtk_main_quit();
}

int main (int argc, char **argv){
GtkBuilder *builder;
GtkWidget *window;
GtkWidget *button;
gtk_init (&argc, &argv);
builder = gtk_builder_new();
gtk_builder_add_from_file(builder, "hello.glade", NULL);
window = GTK_WIDGET(gtk_builder_get_object(builder, "window1"));

button = GTK_WIDGET(gtk_builder_get_object(builder,"button_quit"));
g_signal_connect( G_OBJECT(button), "clicked",
G_CALLBACK(on_button_quit_clicked), NULL);
gtk_builder_connect_signals(builder, NULL);
gtk_widget_show_all(window);
gtk_main();
return 0;
}

Above code could be run correctly, but writing many g_signal_connect is very
tedious.
Is there a way to auto connect callback function to widget designed by glade
or I miss something?

On Thu, Aug 6, 2009 at 12:18 PM, Tristan Van Berkom <

Post by Xiao Yafeng

Post by Xiao Yafeng
I'm new to glade programming. below is my first gtk+ snippet with glade.

[...]

Post by Xiao Yafeng
(hello:8403): Gtk-WARNING **: Could not lookup object NULL on signal

clicked

Post by Xiao Yafeng
of object button_quit
(hello:8403): Gtk-CRITICAL **: gtk_main_quit: assertion `main_loops !=

NULL'

Post by Xiao Yafeng
failed
Segmentation fault
It seems NULL is cause of failure, but who can post a correct code to

prove

Post by Xiao Yafeng
my guess?

The "object" parameter is a string to be set by the user in Glade - I have no
idea how you ended up with the string NULL, it should just be empty if you
dont want to specify an object.
Note also when using the "object" (userdata) field, the specified object will
be swapped with the emitting object and thus come first in the callback`s
argument list (the string specified for "object" is a name of another object
in the same Glade file).
Cheers,
-Tristan

Alexey Kurochkin

2009-08-06 13:15:16 UTC

Permalink

Post by Xiao Yafeng
(hello:12512): Gtk-WARNING **: Could not find signal
handler 'on_button_quit_clicked'
Is there a way to auto connect callback function to widget designed by
glade or I miss something?

Seems like you're missing -export-dynamic flag to gcc. You may want to
read through some glade tutorial. Here's one:
http://www.micahcarrick.com/12-24-2007/gtk-glade-tutorial-part-1.html

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Xiao Yafeng

2009-08-06 13:20:07 UTC

Permalink

I modified Makefile to pkg-config --cflags --libs gtk+-2.0
gmodule_export-2.0
It's Okay! Thanks.

On Thu, Aug 6, 2009 at 9:15 PM, Alexey Kurochkin <

Post by Alexey Kurochkin

Seems like you're missing -export-dynamic flag to gcc. You may want to
http://www.micahcarrick.com/12-24-2007/gtk-glade-tutorial-part-1.html
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