SimpleApiGui

Create A New Gui

/*
             * Create a new Gui: String-Name, Size, Owner
             */
            GuiApi api = new GuiApi("§cGui", 9, null);

Create ItemStack

/*
             * Create Item Stack
             */
            ItemStack item = new ItemStack(Material.DIAMOND);
            ItemStack cobblestone = new ItemStack(Material.COBBLESTONE);

Gui Settings

/*
             * Set DisplayName: ItemStack, String-Name
             */
            api.setDisplayName(item, "§b§oDiamondd");
      
            /*
             * Set Enchantment: ItemStack, Enchantment-Type, Id, Show Enchant(if yes se to true, else set to false)
             */
            api.setEnchantment(item, Enchantment.ARROW_DAMAGE, 1, false);
      
            /*
             * Create List String for Lore
             */
            ArrayList<String> lore = new ArrayList<>();
            lore.add("§eThis is a diamond");
      
            /*
             * Set Lore
             */
            api.setLore(item, lore);
      
            /*
             * Set Item
             */
            api.setItem(item, 4);
            api.setItem(cobblestone, 0);
      
            /*
             * OpenGui To player
             */
            api.open(p);

GuiEvent

@EventHandler
   
    @EventHandler
    public void onClick(GuiEvent e) {
        Player p = e.getPlayer();

        /*
        * Check if you clicked a specify slot, for example slot 4
        */
        if (e.getInventory().equals(inv)) {
            if (e.getClickedSlot() == 4) {
                // do something
                p.sendMessage("You have clicked a diamond");
                p.closeInventory();
            }
        }
        if (e.getInventory().equals(inv2)) {
            if (e.getClickedSlot() == 4) {
                // do something
                p.sendMessage("You have clicked an emerald");
                p.closeInventory();
            }
        }
    }
    }

Example

private Inventory inv;
    private Inventory inv2;

    @EventHandler
    public void onChat(PlayerCommandPreprocessEvent e) {
        String command = e.getMessage();

        Player p = e.getPlayer();

        if (command.equalsIgnoreCase("/opengui")) {
            e.setCancelled(true);
            /*
            * Create a new Gui: String-Name, Size, Owner
            */
            GuiApi api = new GuiApi("§cGui", 9, null);
            inv = api.getInventory();
            /*
            * Create Item Stack
            */
            ItemStack item = new ItemStack(Material.DIAMOND);
            ItemStack cobblestone = new ItemStack(Material.COBBLESTONE);

            /*
            * Set DisplayName: ItemStack, String-Name
            */
            api.setDisplayName(item, "§b§oDiamondd");

            /*
            * Set Enchantment: ItemStack, Enchantment-Type, Id, Show Enchant(if yes se to
            * true, else set to false)
            */
            api.setEnchantment(item, Enchantment.ARROW_DAMAGE, 1, false);

            /*
            * Create List String for Lore
            */
            ArrayList<String> lore = new ArrayList<>();
            lore.add("§eThis is a diamond");

            /*
            * Set Lore
            */
            api.setLore(item, lore);

            /*
            * Set Item
            */
            api.setItem(item, 4);
            api.setItem(cobblestone, 0);

            /*
            * OpenGui To player
            */
            api.open(p);
        }
        if (command.equalsIgnoreCase("/opengui2")) {
            e.setCancelled(true);
            /*
            * Create a new Gui: String-Name, Size, Owner
            */
            GuiApi api = new GuiApi("§cGui2", 9, null);
            inv2 = api.getInventory();
            /*
            * Create Item Stack
            */
            ItemStack item = new ItemStack(Material.EMERALD);
            ItemStack cobblestone = new ItemStack(Material.COBBLESTONE);

            /*
            * Set DisplayName: ItemStack, String-Name
            */
            api.setDisplayName(item, "§2§oEmerald");

            /*
            * Set Enchantment: ItemStack, Enchantment-Type, Id, Show Enchant(if yes se to
            * true, else set to false)
            */
            api.setEnchantment(item, Enchantment.ARROW_DAMAGE, 1, false);

            /*
            * Create List String for Lore
            */
            ArrayList<String> lore = new ArrayList<>();
            lore.add("§eThis is an emerald");

            /*
            * Set Lore
            */
            api.setLore(item, lore);

            /*
            * Set Item
            */
            api.setItem(item, 4);
            api.setItem(cobblestone, 0);

            /*
            * OpenGui To player
            */
            api.open(p);
        }

    }

    @EventHandler
    public void onClick(GuiEvent e) {
        Player p = e.getPlayer();

        /*
        * Check if you clicked a specify slot, for example slot 4
        */
        if (e.getInventory().equals(inv)) {
            if (e.getClickedSlot() == 4) {
                // do something
                p.sendMessage("You have clicked a diamond");
                p.closeInventory();
            }
        }
        if (e.getInventory().equals(inv2)) {
            if (e.getClickedSlot() == 4) {
                // do something
                p.sendMessage("You have clicked an emerald");
                p.closeInventory();
            }
        }
    }