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>How do I validate/limit/filter the input to a GtkEntry? [GTK 2.x]</TITLE
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>How do I validate/limit/filter the input to a GtkEntry? <I
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>[GTK 2.x]</I
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>If you want to validate the text that a user enters into
a GtkEntry widget you can attach to the "insert_text" signal
of the entry, and modify the text within the callback
function. The example below forces all characters to
uppercase, and limits the range of characters to A-Z. Note
that the entry is cast to an object of type GtkEditable, from
which GtkEntry is derived.</P
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CLASS="PROGRAMLISTING"
>#include <ctype.h>
#include <gtk/gtk.h>
void insert_text_handler (GtkEntry *entry,
const gchar *text,
gint length,
gint *position,
gpointer data)
{
GtkEditable *editable = GTK_EDITABLE(entry);
int i, count=0;
gchar *result = g_new (gchar, length);
for (i=0; i < length; i++) {
if (!isalpha(text[i]))
continue;
result[count++] = islower(text[i]) ? toupper(text[i]) : text[i];
}
if (count > 0) {
g_signal_handlers_block_by_func (G_OBJECT (editable),
G_CALLBACK (insert_text_handler),
data);
gtk_editable_insert_text (editable, result, count, position);
g_signal_handlers_unblock_by_func (G_OBJECT (editable),
G_CALLBACK (insert_text_handler),
data);
}
g_signal_stop_emission_by_name (G_OBJECT (editable), "insert_text");
g_free (result);
}
int main (int argc,
char *argv[])
{
GtkWidget *window;
GtkWidget *entry;
gtk_init (&argc, &argv);
/* create a new window */
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_title(GTK_WINDOW (window), "GTK Entry");
g_signal_connect (G_OBJECT (window), "destroy",
G_CALLBACK (gtk_main_quit),
NULL);
entry = gtk_entry_new();
g_signal_connect(G_OBJECT(entry), "insert_text",
G_CALLBACK(insert_text_handler),
NULL);
gtk_container_add(GTK_CONTAINER (window), entry);
gtk_widget_show(entry);
gtk_widget_show(window);
gtk_main();
return(0);
}</PRE
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