Show a label with a message...

[pks timing com]

what's wrong ------------------------------------------------------------

 > GtkWidget *message;
 > GtkWidget *caja1;

 > int main(int argc, char *argv[])
 > {
 >    caja1 = gtk_hbox_new(TRUE, 0);
 >    message = gtk_label_new(" ");
 >    gtk_box_pack_start(GTK_BOX(caja1), message, TRUE, TRUE, 0);
 > }

in the code above you are:
1) creating an hbox.
2) creating a label that is to display text " "
3) packing the label in the hbox.

gtk_label_new() instantiates a brand new label and
initializes it's text.

 > void salute (GtkWidget *widget, gpointer data)
 > {
 >   message = gtk_label_new("This is GTK programming.");
 > }

 > void salute_hide (GtkWidget *widget, gpointer data)
 > {
 >   message = gtk_label_new(" ");
 > }

in both of these functions you *instantiating* yet another
label, which is never packed anywhere or shown. This is
not what you want to do ...


what you're likely trying to get done -----------------------------------


is to change the text of the label you have created in main() instead
of creating a new one:

 > void salute (GtkWidget *widget, gpointer data)
 > {
 >   gtk_label_set_text(GTK_LABEL(message), "This is GTK programming.");
 > }

 > void salute_hide (GtkWidget *widget, gpointer data)
 > {
 >   gtk_label_set_text(GTK_LABEL(message), "This is GTK programming.");
 > }

or to show and and hide the label all together:

 > int main(int argc, char *argv[])
 > {
 >    caja1 = gtk_hbox_new(TRUE, 0);
 >    message = gtk_label_new("This is GTK programming.");
 >    gtk_box_pack_start(GTK_BOX(caja1), message, TRUE, TRUE, 0);
 > }

 > void salute (GtkWidget *widget, gpointer data)
 > {
 >   gtk_widget_show(message);
 > }

 > void salute_hide (GtkWidget *widget, gpointer data)
 > {
 >   gtk_widget_hide(message);
 > }


something for the heck of it --------------------------------------------

change your exising implementations of:

 > void salute (GtkWidget *widget, gpointer data)
 > {
 >   message = gtk_label_new("This is GTK programming.");
 > }

 > void salute_hide (GtkWidget *widget, gpointer data)
 > {
 >   message = gtk_label_new(" ");
 > }

to

 > void salute (GtkWidget *widget, gpointer data)
 > {
 >   message = gtk_label_new("new SALUTE label.");
 >   gtk_box_pack_start(GTK_BOX(caja1), message, TRUE, TRUE, 0);
 >   gtk_widget_show(message);
 > }

 > void salute_hide (GtkWidget *widget, gpointer data)
 > {
 >   message = gtk_label_new("new HIDE label.");
 >   gtk_box_pack_start(GTK_BOX(caja1), message, TRUE, TRUE, 0);
 >   gtk_widget_show(message);
 > }


and you'll have a better understanding of what you
were doing to begin with.

Note that overwriting the *message pointer with the newly
allocated widgets probably isn't good practice.

The only way you'll get a reference to the labels you
have instantiated before the most recent one (to change
text, show/hide, or even deallocate them) is by means of
access functions on the container you stuffed them into
(such as gtk_container_children()).


and because I'm feeling fat and sassy --------------------------------


> my idea is that i am doing a bad use of gtk_label_new() or
> gtk_signal_connect() functions, but......

if you're worried about the signal handlers not being called
you can add something as simple as printf() to the signal
handler ...

 > void salute_hide (GtkWidget *widget, gpointer data)
 > {
 >   printf("Show button was pressed\n");
 > }

and check output on the terminal window you started
your application from.


now go and read some more examples - you'll figure it out ;)