Solved Items in an inventory change?

How do i make items in an inventory change when opened, like stained glass changing colors every seconds etc. I tried InventoryOpenEvent, and setting the items in the inventory but it doesn't work.

EDIT: Don't worry, i was just doing the runnable wrong xD

 

@dlange Post the solution you found for the world to see please :- )
Also be sure not to start infinite repeating tasks in event bodies.

 

@mine-care What do you suggest instead? That's what i did, but i agree it's not the best idea. I could have a method that's called from the event, would probs be the same thing, idk.

This is what i did:

Code:

    @EventHandler
    public void onInvOpen(final InventoryOpenEvent e) {
        if (e.getInventory().getName().equals(Inventories.duelInventory().getName())) {
            new BukkitRunnable() {
                @Override
                public void run() {
                    Inventory inv = e.getInventory();
                    byte b1;
                    ItemStack item = null;
                    if (inv.getItem(0).equals(new ItemStack(Material.STAINED_GLASS_PANE, 1, (byte) 8))) {
                        b1 = (byte) 14;
                        item = new ItemStack(Material.STAINED_GLASS_PANE, 1, b1);
                    } else {
                        b1 = (byte) 8;
                        item = new ItemStack(Material.STAINED_GLASS_PANE, 1, b1);
                    }
                    ItemMeta itemm = item.getItemMeta();
                    itemm.setDisplayName(" ");
                    item.setItemMeta(itemm);

                    for (int i = 0; i < 9; i++) {
                        inv.setItem(i - 1, item);
                    }

                    for (int i = 27; i < 36; i++) {
                        inv.setItem(i, item);
                    }
                }
            }.runTaskTimer(Duel.getPlugin(), 5L, 5L);
        }
    }