Solved Checking if an item is clicked on another item

I'm currently trying to figure out how I would check whether a player clicks an item using another item already selected in their inventory. If you don't quite understand what I mean, here is a photo:


This is my code so far, but it isn't work.

Code (Text):

        @EventHandler
        public void onInventoryClick(InventoryClickEvent event) {
            Player p = (Player) event.getWhoClicked();
            p.sendMessage("2");
            Inventory inventory = event.getInventory();
            ItemStack clicked = event.getCurrentItem();
            if (clicked.getItemMeta().getDisplayName().equals(ChatColor.GREEN + "" + ChatColor.BOLD + "Respiration I")) {
                p.sendMessage("1");
                if (p.getItemOnCursor().equals(Material.DIAMOND_HELMET)) {
                    p.sendMessage("3");
                }
            }
        }

 

How would I check what is being swapped and what the cursor item is?