GTK implementation of MessageBox

Question

I have been trying to implement Win32's MessageBox using GTK. The app uses SDL/OpenGL, so this isn't a GTK app.

I handle the initialization (gtk_init) sort of stuff inside the MessageBox function as follows:

int MessageBox(HWND hwnd, const char* text, const char* caption, UINT type)
{
    GtkWidget *window = NULL;
    GtkWidget *dialog = NULL;

    gtk_init(&gtkArgc, &gtkArgv);
    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    g_signal_connect(G_OBJECT(window), "delete_event", G_CALLBACK(delete_event), NULL);
    g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(destroy), NULL);
    // gcallback calls gtk_main_quit()
    gtk_init_add((GtkFunction)gcallback, NULL);

    if (type & MB_YESNO) {
        dialog = gtk_message_dialog_new(GTK_WINDOW(window), GTK_DIALOG_DESTROY_WITH_PARENT, GTK_MESSAGE_QUESTION, GTK_BUTTONS_YES_NO, text);
    } else {
        dialog = gtk_message_dialog_new(GTK_WINDOW(window), GTK_DIALOG_DESTROY_WITH_PARENT, GTK_MESSAGE_INFO, GTK_BUTTONS_OK, text);
    }

    gtk_window_set_title(GTK_WINDOW(dialog), caption);
    gint result = gtk_dialog_run(GTK_DIALOG(dialog));

    gtk_main();

    gtk_widget_destroy(dialog);

    if (type & MB_YESNO) {
        switch (result) {
        default:
        case GTK_RESPONSE_DELETE_EVENT:
        case GTK_RESPONSE_NO:
            return IDNO;
            break;
        case GTK_RESPONSE_YES:
            return IDYES;
            break;
        }
    }

    return IDOK;
} 

Now, I am by no means an experienced GTK programmer, and I realize that I'm probably doing something horribly wrong.

However, my problem is that the last dialog popped up with this function staying around until the process exits. Any ideas?

Answer 1

Hmm, ok. I'd suggest code like this, then:

typedef struct {
    int type;
    int result;
} DialogData;
    
static gboolean
display_dialog(gpointer user_data)
{
    DialogData *dialog_data = user_data;
    GtkWidget *dialog;
    
    if (dialog_data->type & MB_YESNO)
        dialog = gtk_message_dialog_new(...);
    else
        dialog = gtk_message_dialog_new(...);
    
    // Set title, etc.
    
    dialog_data->result = gtk_dialog_run(...);
    
    gtk_main_quit();  // Quits the main loop run in MessageBox()
    
    return FALSE;
}
    
int MessageBox(...)
{
    DialogData dialog_data;
    
    dialog_data.type = type;
    
    gtk_idle_add(display_dialog, &dialog_data);
    
    gtk_main();
    
    // Do stuff based on dialog_data.result
}

The struct is required because you need to pass around a couple pieces of data. The gtk_idle_add() call adds a method to be run when the main loop is running and idle, and the FALSE return value from the display_dialog() call means that it's only run once. After we get the result from the dialog, we quit the main loop. That'll cause the gtk_main() in your main MessageBox() method to return, and you'll be able to access the result from there.