InvMenu is a PocketMine-MP virion that eases creating and managing fake inventories!

You can get the compiled .phar file on poggit by clicking here.

InvMenu supports creating a GUI out of any kind of Inventory.

NOTE: You MUST register InvMenuHandler during plugin enable before you can begin creating InvMenu instances.

if(!InvMenuHandler::isRegistered()){
	InvMenuHandler::register($this);
}

InvMenu::create($identifier) creates a new instance of InvMenu. $identifier must be an identifier of a registered InvMenuType object. InvMenu comes with 3 pre-registered InvMenuType identifiers: InvMenu::TYPE_CHEST, InvMenu::TYPE_DOUBLE_CHEST and InvMenu::TYPE_HOPPER.

$menu = InvMenu::create(InvMenu::TYPE_CHEST);

To access this menu's inventory, you can use:

$inventory = $menu->getInventory();

The $inventory implements pocketmine's Inventory interface, so you can access all the fancy pocketmine inventory methods.

$menu->getInventory()->setContents([
	VanillaItems::DIAMOND_SWORD(),
	VanillaItems::DIAMOND_PICKAXE()
]);
$menu->getInventory()->addItem(VanillaItems::DIAMOND_AXE());
$menu->getInventory()->setItem(3, VanillaItems::GOLD_INGOT());

To send the menu to a player, use:

/** @var Player $player */
$menu->send($player);

Yup, that's it. It's that simple.

To set a custom name to a menu, use

$menu->setName("Custom Name");

You can also specify a different menu name for each player separately during InvMenu::send().

/** @var Player $player */
$menu->send($player, "Greetings, " . $player->getName());

Not a common occurrence but it's possible for plugins to disallow players from opening inventories. This can also occur as an attempt to drop garbage InvMenu::send() requests (if you send two menus simultaneously without any delay in betweeen, the first menu request may be regarded as garbage).

/** @var string|null $name */
$menu->send($player, $name, function(bool $sent) : void{
	if($sent){
		// do something
	}
});

To handle item transactions happening to and from the menu's inventory, you may specify a Closure handler that gets triggered by InvMenu every time a transaction occurs. You may allow, cancel and do other things within this handler. To register a transaction handler to a menu, use:

/** @var Closure $listener */
$menu->setListener($listener);

What's $listener?

/**
 * @param InvMenuTransaction $transaction
 *
 * Must return an InvMenuTransactionResult instance.
 * Return $transaction->continue() to continue the transaction.
 * Return $transaction->discard() to cancel the transaction.
 * @return InvMenuTransactionResult
 */
Closure(InvMenuTransaction $transaction) : InvMenuTransactionResult;

InvMenuTransaction holds all the item transction data.
InvMenuTransaction::getPlayer() returns the Player that triggered the transaction.
InvMenuTransaction::getItemClicked() returns the Item the player clicked in the menu.
InvMenuTransaction::getItemClickedWith() returns the Item the player had in their hand when clicking an item.
InvMenuTransaction::getAction() returns a SlotChangeAction instance, to get the slot index of the item clicked from the menu's inventory.
InvMenuTransaction::getTransaction() returns the complete InventoryTransaction instance.

$menu->setListener(function(InvMenuTransaction $transaction) : InvMenuTransactionResult{
	$player = $transaction->getPlayer();
	$itemClicked = $transaction->getItemClicked();
	$itemClickedWith = $transaction->getItemClickedWith();
	$action = $transaction->getAction();
	$invTransaction = $transaction->getTransaction();
	return $transaction->continue();
});

A handler that doesn't allow players to take out apples from the menu's inventory:

$menu->setListener(function(InvMenuTransaction $transaction) : InvMenuTransactionResult{
	if($transaction->getItemClicked()->getId() === ItemIds::APPLE){
		$player->sendMessage("You cannot take apples out of that inventory.");
		return $transaction->discard();
	}
	return $transaction->continue();
});

There are two ways you can go with to prevent players from modifying the inventory contents of a menu.

$menu->setListener(function(InvMenuTransaction $transaction) : InvMenuTransactionResult{
	// do something
	return $transaction->discard();
});

$menu->setListener(InvMenu::readonly());

$menu->setListener(InvMenu::readonly(function(DeterministicInvMenuTransaction $transaction) : void{
	// do something
}));

Based on your use-case, you may find one better than the other. While Method #1 gives you full control over a transaction (you can conditionally cancel a transaction, f.e based on whether player has permission, or player is in a specific area etc), Method #2 reduces boilerplate InvMenuTransactionResult imports and calls to InvMenutransaction::discard().

A few actions are impossible to be done at the time a player is viewing an inventory, such as sending a form — a player won't be able to view a form while viewing an inventory. To do this, you will need to close the menu inventory and make sure they've closed it by waiting for a response from their side. You can do this by supplying a callback to InvMenuTransactionResult::then().

$menu->setListener(function(InvMenuTransaction $transaction) : InvMenuTransactionResult{
	$transaction->getPlayer()->removeCurrentWindow();
	return $transaction->discard()->then(function(Player $player) : void{ // $player === $transaction->getPlayer()
		// assert($player->isOnline());
		$player->sendForm(new Form());
	});
});

$menu->setListener(InvMenu::readonly(function(DeterministicInvMenuTransaction $transaction) : void{
	$transaction->getPlayer()->removeCurrentWindow();
	$transaction->then(function(Player $player) : void{
		$player->sendForm(new Form());
	});
}));

To listen inventory close triggers, specify the inventory close Closure using:

/** @var Closure $listener */
$menu->setInventoryCloseListener($listener);

What's $listener?

/**
 * @param Player $player the player who closed the inventory.
 *
 * @param Inventory $inventory the inventory instance closed by the player.
 */
Closure(Player $player, Inventory $inventory) : void;

To forcefully close or remove the menu from a player:

/** @var Player $player */
$player->removeCurrentWindow();

So let's say you'd like to send players a dispenser inventory. While InvMenu doesn't ship with a InvMenu::TYPE_DISPENSER, you can still create a dispenser InvMenu by registering an InvMenuType object with the information about what a dispenser inventory looks like.

public const TYPE_DISPENSER = "myplugin:dispenser";

protected function onEnable() : void{
	InvMenuHandler::getTypeRegistry()->register(self::TYPE_DISPENSER, InvMenuTypeBuilders::BLOCK_ACTOR_FIXED()
		->setBlock(BlockFactory::getInstance()->get(BlockLegacyIds::DISPENSER, 0))
		->setBlockActorId("Dispenser")
		->setSize(9)
		->setNetworkWindowType(WindowTypes::DISPENSER)
	->build());
}

Sweet! Now you can create a dispenser menu using

$menu = InvMenu::create(self::TYPE_DISPENSER);

Applications, examples, tutorials and featured projects using InvMenu can be found on the InvMenu Wiki.