Midhun A wrote:
> Hi All,
>
> I am very new to GTK+ (started out yesterday). I am writing a simple
> application which will show pictures one by one on button click.
> Although I am able to get my first picture, the picture does not
> change on click of the button (next or previous). The full code is as
> below.
>
> #include <stdio.h>
> #include <gtk/gtk.h>
> #include <string.h>
> #include <unistd.h>
> #include </usr/include/stdio.h>
> #include <glib.h>
>
> GtkWidget *image2;
> GtkWidget *window;
> GtkWidget *vbox;
> GtkWidget *prev_button, *next_button;
>
>
>
> gchar *files[6] =
> {
> "/home/pics/1.jpg",
> "/home/pics/2.jpg",
> "/home/pics/3.jpg",
> "/home/pics/4.jpg",
> "/home/pics/5.jpg",
> "/home/pics/6.jpg"
> };
>
> typedef struct{
> gint data;
> } data;
>
> void prev_callback (GtkWidget *widget, data *v )
> {
> gint cnt = v->data;
> if (cnt == 0)
> cnt = 5;
> else
> cnt = cnt - 1;
>
> image2 = gtk_image_new_from_file (files[cnt]);
> }
This callback only creates the new image, it doesn't display it in the
window. You seem to lack basic C understanding, especially about pointers.
To replace the current image, you have to remove the image widget from
the vbox and replace it with the new image. Like this:
> void next_callback (GtkWidget *widget, data *v)
> {
> int cnt = v->data;
> if (cnt == 5)
> cnt = 0;
> else
> cnt = cnt + 1;
>
gtk_container_remove(GTK_CONTAINER(vbox), image2);
> image2 = gtk_image_new_from_file (files[cnt]);
gtk_container_add(GTK_CONTAINER(vbox), image2);
> }
>
>
> int main (int argc, char *argv[])
> {
>
> data *w = g_slice_new(data);
> w->data = 0;
>
> gtk_init(&argc,&argv);
> window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
> gtk_window_maximize (window);
>
> vbox = gtk_vbox_new(FALSE, 1);
>
> image2 = gtk_image_new_from_file (files[w->data]);
> gtk_container_add(GTK_CONTAINER(vbox), image2);
>
> prev_button = gtk_button_new_with_mnemonic ("Previous");
> next_button = gtk_button_new_with_mnemonic ("Next");
>
> gtk_widget_set_name(prev_button,"prev_button");
> gtk_widget_set_name(next_button,"next_button");
>
> gtk_container_add(GTK_CONTAINER(vbox), prev_button);
> gtk_container_add(GTK_CONTAINER(vbox), next_button);
> gtk_container_add(GTK_CONTAINER(window), vbox);
>
> g_signal_connect (G_OBJECT (prev_button), "clicked", G_CALLBACK
> (prev_callback),(gpointer)w);
> g_signal_connect (G_OBJECT (next_button), "clicked", G_CALLBACK
> (next_callback),(gpointer)w);
>
> gtk_widget_show (image2);
> gtk_widget_show (prev_button);
> gtk_widget_show (next_button);
> gtk_widget_show (vbox);
> gtk_widget_show (window);
>
> gtk_main();
> return 0;
> }
>
>
> This is very primitive code to test the functionality. Whats wrong
> with the code? I would like to see the previous picture on click of
> previous button and the next picture on click of next button.
>
tom
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