# SpinButton (C)

Monica Kochofar
monicakochofar@gmail.com 2012
Retrieve an integer or floating point number
Rafael Fontenelle
rafaelff@gnome.org 2013, 2018

# SpinButton

Choose a number, by entering it or by clicking on the -/+ buttons!

#include <gtk/gtk.h>

/* This is the callback function. * It is a handler function which reacts to the signal. * In this case, it will notify the user the value of their spinbutton * as a label. */ static void spin_clicked (GtkSpinButton *spinbutton, gpointer user_data) { GtkWidget *label = user_data; gint value = gtk_spin_button_get_value_as_int (spinbutton);

/* %d - Is used when printing integers. * Note: Using g_strdup_printf returns a string that must be freed. * (In which is done below) */ gchar *str = g_strdup_printf ("The number you selected is %d.", value); gtk_label_set_text (GTK_LABEL (label), str);

g_free(str); }

static void activate (GtkApplication *app, gpointer user_data) { /* Declare variables */ GtkWidget *window; GtkWidget *label; GtkWidget *grid; GtkWidget *spin_button; GtkAdjustment *adjustment;

/* Create a window with a title, a border width, and a default size */ window = gtk_application_window_new (app); gtk_window_set_title (GTK_WINDOW (window), "SpinButton Example"); gtk_window_set_default_size (GTK_WINDOW (window), 210, 70); gtk_container_set_border_width (GTK_CONTAINER (window), 5);

/* Create a label to be shown in the window */ label = gtk_label_new ("Choose a number");

/* Create an adjustment representing an adjustable bounded value */ adjustment = gtk_adjustment_new (0, 0, 100, 1, 0, 0);

/* Create a spin button that is to be as wide as possible */ spin_button = gtk_spin_button_new (adjustment, 1, 0); gtk_widget_set_hexpand (spin_button, TRUE);

/* Connecting the "value-changed" signal for the spinbutton * to the appropriate callback function. */ g_signal_connect (spin_button, "value-changed", G_CALLBACK (spin_clicked), label);

/* Create a grid and arrange everything accordingly */ grid = gtk_grid_new (); gtk_grid_set_column_spacing (GTK_GRID (grid), 10); gtk_grid_set_column_homogeneous (GTK_GRID (grid), TRUE); gtk_grid_attach (GTK_GRID (grid), spin_button, 0, 0, 1, 1); gtk_grid_attach (GTK_GRID (grid), label, 0, 1, 1, 1);

gtk_container_add (GTK_CONTAINER (window), grid);

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

GtkSpinButton

GtkLabel

GtkAdjustment

GtkGrid