# Button (C)

Monica Kochofar
monicakochofar@gmail.com 2012
A button widget which emits a signal when clicked
Rafael Ferreira
rafael.f.f1@gmail.com 2013

# Button

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; }

In this sample we used the following:

GtkApplication

GtkWindow

GtkButton

Unicode Manipulation