Now let's subclass GtkWindow and imagine that we want to change the behavior of the set_title function of GtkWindow. The function is used to set the window's title with the specified string passed in the argument. The new behavior that we want to introduce here is to always add a special word into the window's title whenever we set the set_title function.
Create a new Vala project called
custom-overriding.In the
src/custom_overriding.valafile, use the following code:using GLib; using Gtk; public class CustomWindow : Window { public CustomWindow () { } public new void set_title(string newTitle) { title = "Custom: " + newTitle; } static int main (string[] args) { Gtk.init (ref args); var window = new CustomWindow (); window.set_title ("My window"); window.show_all (); window.destroy.connect(Gtk.main_quit); Gtk.main (); return 0; } }Our JavaScript equivalent code looks...