A button widget connected to a callback function that reverses its label when clicked.
#include <gtk/gtk.h>
/*This is the callback function. It is a handler function which
reacts to the signal. In this case, it will cause the button label's
string to reverse.*/
static void
button_clicked (GtkButton *button,
gpointer user_data)
{
const char *old_label;
char *new_label;
old_label = gtk_button_get_label (button);
new_label = g_utf8_strreverse (old_label, -1);
gtk_button_set_label (button, new_label);
g_free (new_label);
}
static void
activate (GtkApplication *app,
gpointer user_data)
{
GtkWidget *window;
GtkWidget *button;
/*Create a window with a title and a default size*/
window = gtk_application_window_new (app);
gtk_window_set_title (GTK_WINDOW (window), "GNOME Button");
gtk_window_set_default_size (GTK_WINDOW (window), 250, 50);
/*Create a button with a label, and add it to the window*/
button = gtk_button_new_with_label ("Click Me");
gtk_container_add (GTK_CONTAINER (window), button);
/*Connecting the clicked signal to the callback function*/
g_signal_connect (GTK_BUTTON (button),
"clicked",
G_CALLBACK (button_clicked),
G_OBJECT (window));
gtk_widget_show_all (window);
}
int
main (int argc, char **argv)
{
GtkApplication *app;
int status;
app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);
g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
status = g_application_run (G_APPLICATION (app), argc, argv);
g_object_unref (app);
return status;
}
Neste exemplo empregaremos o seguinte:
GtkApplication
GtkWindow
GtkButton
Unicode Manipulation