This is the PocketMine virion that implements the dummy inventory.

• Chests and other blocks are not placed.
• If a player falls or moves by water or other means when the inventory is open, the inventory will not close.
• You can specify any number of slots in your inventory. (Up to 1000 confirmed)
• Vertical length of inventory slots can be specified. (max. 6)

1. Download InventoryUIResourcePack.mcpack and put it in the resource_packs folder
2. Open file resource_packs.yml, set force_resources to true and resource_stack to InventoryUIResourcePack.mcpack

force_resources: true
resource_stack:
  - InventoryUIResourcePack.mcpack

The following code must be called when the plugin is enabled.

InventoryUI::setup($this);

$slot specifies the number of slots in the inventory and must be a number greater than zero.
$title is the name of the inventory.
$length is entered as the vertical length of the inventory. If null, it is automatically adjusted.

/** @var Player $player */
$player->setCurrentWindow(new CustomInventory($slot, $title, $length));

class SampleInventory extends CustomInventory {

    public function __construct() {
        parent::__construct(54, "Sample Inventory");
    }

    public function open(Player $player): void {
        // Called when a player opens this inventory.
    }

    public function tick(int $tick): void {
        // Called every tick when someone opens inventory.
    }

    public function click(Player $player, int $slot, Item $sourceItem, Item $targetItem): bool {
        // It is called when a slot in the inventory is operated.
        // If the return value is true, the operation is canceled.
        return false;
    }

    public function close(Player $player): void {
        // Called when the player closes the inventory.
    }
}

Sample plugin here

"InventoryUI" is under MIT License

Help resource pack @famima65536