create an headbar with about dialog in GTK+3 - c

Question

I'm trying to create a head bar that should contain an "About" labelled button to show up a dialog when clicked.
#include <gtk/gtk.h>
static void activate_about(GtkWidget *window, gpointer data);
int main(int argc, char *argv[]) {
gtk_init(&argc, &argv);
GtkWidget *window;
GtkWidget *vbox;
GtkWidget *about_button;
GtkWidget *headbar;
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
gtk_window_set_default_size(GTK_WINDOW(window), 300, 200);
headbar = gtk_header_bar_new();
gtk_header_bar_set_title (GTK_HEADER_BAR (headbar), "Welcome to GTK");
gtk_header_bar_set_show_close_button (GTK_HEADER_BAR (headbar), TRUE);
vbox = gtk_box_new(GTK_ORIENTATION_VERTICAL, 12);
about_button = gtk_button_new_with_mnemonic("_About");
gtk_container_add(GTK_CONTAINER(window), vbox);
gtk_container_add(GTK_CONTAINER(vbox), headbar);
gtk_container_add(GTK_CONTAINER(headbar), about_button);
g_signal_connect(about_button, "clicked",
G_CALLBACK(activate_about), NULL);
gtk_widget_show_all(window);
gtk_main();
return 0;
}
static void activate_about(GtkWidget *window, gpointer data) {
const gchar *authors[] = {"ad Chi", NULL};
gtk_show_about_dialog(GTK_WINDOW(window),
"program-name", "jjkjk",
"version", "0.0.1",
"copyright", "(C) 2017 ad Chi",
"license-type", GTK_LICENSE_GPL_3_0,
"website", "https://github.com/kjk",
"comments", "Totally kj",
"authors", authors,
"documenters", NULL,
"logo-icon-name", "start-here",
"title", "About kj kj",
NULL);
return;
}
The first issue is that now I end up with two bars the window one and that of the headbar widget. I need just one. The second problem is, when I click the button I get
(button:1727): GLib-GObject-WARNING **: 17:59:47.965: invalid cast from 'GtkButton' to 'GtkWindow'
(button:1727): Gtk-CRITICAL **: 17:59:47.982: gtk_window_set_transient_for: assertion 'parent == NULL || GTK_IS_WINDOW (parent)' failed. I am new to GTK. I suppose that gtk_show_about_dialog(GTK_WINDOW(window)... is not the proper widget to use.

Answer 1

#include <gtk/gtk.h>
static void activate_about(GtkWidget *widget, gpointer window);
int main(int argc, char *argv[]) {
gtk_init(&argc, &argv);
GtkWidget *window;
GtkWidget *vbox;
GtkWidget *about_button;
GtkWidget *headbar;
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
gtk_window_set_default_size(GTK_WINDOW(window), 300, 200);
headbar = gtk_header_bar_new();
gtk_header_bar_set_title (GTK_HEADER_BAR (headbar), "Welcome to GTK");
gtk_header_bar_set_show_close_button (GTK_HEADER_BAR (headbar), TRUE);
vbox = gtk_box_new(GTK_ORIENTATION_VERTICAL, 12);
about_button = gtk_button_new_with_mnemonic("_About");
gtk_container_add(GTK_CONTAINER(window), vbox);
gtk_window_set_titlebar(GTK_WINDOW(window), headbar);
gtk_header_bar_pack_start(GTK_HEADER_BAR(headbar), about_button);
g_signal_connect(about_button, "clicked",
G_CALLBACK(activate_about), window);
g_signal_connect_swapped (window, "destroy",
G_CALLBACK (gtk_main_quit), NULL);
gtk_widget_show_all(window);
gtk_main();
return 0;
}
static void activate_about(GtkWidget *widget, gpointer window) {
const gchar *authors[] = {"ad Chi", NULL};
gtk_show_about_dialog(GTK_WINDOW(window),
"program-name", "jjkjk",
"version", "0.0.1",
"copyright", "(C) 2017 ad Chi",
"license-type", GTK_LICENSE_GPL_3_0,
"website", "https://github.com/kjk",
"comments", "Totally kj",
"authors", authors,
"documenters", NULL,
"logo-icon-name", "start-here",
"title", "About kj kj",
NULL);
return;
}