Re: Help spinbuttons

[Paulo Silva <paulo sistemasolar com br>]

Hello Roger.

I think you misunderstand the concept of callback functions. In your
example there is no appropriated callback function to deal with the changes
of spin button. And another thing, the 3rd parameters to register a
callback function must be a pointer.

I suggest to take a look at chapter 2 under "Signals and Callbacks" section.

José Paulo


2015-03-16 23:24 GMT-03:00 Roger Matthews <roger matthews hotmail com>:

> /* I want a window containing many spinbuttons for both
> integers and floating-point numbers, these may then be either 1) left
> unchanged, or 2) changed to a new value. Then, whether changed or
> unchanged,
> use the integers and floats as input parameters into various calculations.
> As
> it is the printf() statements only show the unchanged values. */
>
>
>
> /*The example below is taken from page 90 of
> "Foundations of GTK+ Development" by Andrew Krause*/
>
>
>
> #include <stdio.h>
>
> #include <gtk/gtk.h>
>
>
>
> int main(int argc, char *argv[])
>
> {
>
> GtkWidget *window, *spin_int, *spin_float;
>
> GtkAdjustment *integer, *float_pt;
>
>
>
> gint number_int;
>
> gdouble number_double;
>
>
>
> gtk_init (&argc, &argv);
>
>
>
> window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
>
> gtk_window_set_title (GTK_WINDOW (window), "Spin Buttons");
>
> gtk_container_set_border_width (GTK_CONTAINER(window), 10);
>
> gtk_widget_set_size_request (window, 150, 100);
>
>
>
> integer = GTK_ADJUSTMENT (gtk_adjustment_new (5.0, 0.0,
> 10.0, 1.0, 2.0, 2.0));
>
> float_pt = GTK_ADJUSTMENT (gtk_adjustment_new (0.5, 0.0, 1.0,
> 0.1, 0.5, 0.5));
>
>
>
> spin_int = gtk_spin_button_new (integer, 1.0, 0);
>
> spin_float = gtk_spin_button_new (float_pt, 0.1, 1);
>
>
>
> gtk_container_add (GTK_CONTAINER (window), spin_int);
>
> gtk_container_add (GTK_CONTAINER (window), spin_float);
>
>
>
> gtk_widget_show_all (window);
>
>
>
> number_int=gtk_spin_button_get_value_as_int(spin_int);
>
> number_double=gtk_spin_button_get_value(spin_float);
>
>
>
>   g_signal_connect
> (integer, "change-value", G_CALLBACK (spin_int), number_int);
>
>
>
>   g_print ("Hello
> World\n");
>
>   g_print
> ("g_print Before gtk_main, integer %d\n", number_int);
>
>   printf("printf
> Before gtk_main, integer %d\n", number_int);
>
>   printf("printf
> Before gtk_main, double %f\n", number_double);
>
>
>
> gtk_main ();
>
>
>
>   printf("Hello
> World\n");
>
>   printf("After
> gtk_main %d\n", number_int);
>
>
>
> return 0;
>
> }
>
>
> /********************************************************************************/
>
> /*Below are the commands to edit, compile and execute the
> program, and the warnings, messages and output to the terminal. At this
> stage
> the warnings are unimportant, I merely want to be able to read or save
> both the
> unchanged and changed values displayed in the spinbutton(s).*/
>
> /*
>
>
>
> $ gedit page90.c
>
>
>
> $ gcc `pkg-config --cflags gtk+-3.0` -o page90.exe page90.c
> `pkg-config --libs gtk+-3.0`
>
>
>
> $ ./page90.exe
>
>
>
> (page90.exe:2614): Gtk-WARNING **: Attempting to add a
> widget with type GtkSpinButton to a GtkWindow, but as a GtkBin subclass a
> GtkWindow can only contain one widget at a time; it already contains a
> widget
> of type GtkSpinButton
>
>
>
> (page90.exe:2614): GLib-GObject-WARNING **:
> /build/buildd/glib2.0-2.38.1/./gobject/gsignal.c:2475: signal
> 'change-value' is
> invalid for instance '0xee5350' of type 'GtkAdjustment'
>
> Hello World
>
> g_print Before gtk_main, integer 5
>
> printf Before gtk_main, integer 5
>
> printf Before gtk_main, double 0.500000*/
>
>
> /*******************************************************************************/
>
>
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