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将物品放在容器中
阅读本教程之前,请确保您已将方块实体制作完成。
将物品存储在BlockEntity中的标准方法是使其成为Inventory
。
这使得漏斗(或其他mods)无需任何额外的工作即可从您的BlockEntity放入和提取物品。
实现Inventory接口
Inventory
只是一个接口,这意味着实际的ItemStack
状态将需要存储在您的BlockEntity
上。
可以使用DefaultedList <ItemStack>
作为存储这些ItemStacks
的简便方法,
因为可以将其默认设置为ItemStack.Empty
,这是表示插槽中没有项目的正确方法。
实现Inventory
非常简单,但乏味且容易出错,
因此,我们将使用它的默认实现,该实现只需要给它一个DefaultList <ItemStack>
(将其复制为新文件):
- ImplementedInventory.java
/** * A simple {@code Inventory} implementation with only default methods + an item list getter. * * Originally by Juuz */ public interface ImplementedInventory extends Inventory { /** * Retrieves the item list of this inventory. * Must return the same instance every time it's called. */ DefaultedList<ItemStack> getItems(); /** * Creates an inventory from the item list. */ static ImplementedInventory of(DefaultedList<ItemStack> items) { return () -> items; } /** * Creates a new inventory with the specified size. */ static ImplementedInventory ofSize(int size) { return of(DefaultedList.ofSize(size, ItemStack.EMPTY)); } /** * Returns the inventory size. */ @Override default int size() { return getItems().size(); } /** * Checks if the inventory is empty. * @return true if this inventory has only empty stacks, false otherwise. */ @Override default boolean isEmpty() { for (int i = 0; i < size(); i++) { ItemStack stack = getStack(i); if (!stack.isEmpty()) { return false; } } return true; } /** * Retrieves the item in the slot. */ @Override default ItemStack getStack(int slot) { return getItems().get(slot); } /** * Removes items from an inventory slot. * @param slot The slot to remove from. * @param count How many items to remove. If there are less items in the slot than what are requested, * takes all items in that slot. */ @Override default ItemStack removeStack(int slot, int count) { ItemStack result = Inventories.splitStack(getItems(), slot, count); if (!result.isEmpty()) { markDirty(); } return result; } /** * Removes all items from an inventory slot. * @param slot The slot to remove from. */ @Override default ItemStack removeStack(int slot) { return Inventories.removeStack(getItems(), slot); } /** * Replaces the current stack in an inventory slot with the provided stack. * @param slot The inventory slot of which to replace the itemstack. * @param stack The replacing itemstack. If the stack is too big for * this inventory ({@link Inventory#getMaxCountPerStack()}), * it gets resized to this inventory's maximum amount. */ @Override default void setStack(int slot, ItemStack stack) { getItems().set(slot, stack); if (stack.getCount() > getMaxCountPerStack()) { stack.setCount(getMaxCountPerStack()); } } /** * Clears the inventory. */ @Override default void clear() { getItems().clear(); } /** * Marks the state as dirty. * Must be called after changes in the inventory, so that the game can properly save * the inventory contents and notify neighboring blocks of inventory changes. */ @Override default void markDirty() { // Override if you want behavior. } /** * @return true if the player can use the inventory, false otherwise. */ @Override default boolean canPlayerUse(PlayerEntity player) { return true; } }
现在在您的BlockEntity
中实施ImplementedInventory
,
并为其提供存储该项目的DefaultedList <ItemStack>项目
实例。
对于此示例,我们将在库存中最多存储2件物品:
public class DemoBlockEntity extends BlockEntity implements ImplementedInventory { private final DefaultedList<ItemStack> items = DefaultedList.ofSize(2, ItemStack.EMPTY); @Override public DefaultedList<ItemStack> getItems() { return items; } [...] }
我们还需要保存容器以标记并从那里加载。
Inventories
具有帮助方法,可以非常轻松地完成此任务:
public class DemoBlockEntity extends BlockEntity implements ImplementedInventory { [...] @Override public void readNbt(NbtCompound nbt) { super.readNbt(nbt); Inventories.readNbt(nbt, items); } @Override public NbtCompound writeNbt(NbtCompound nbt) { Inventories.writeNbt(nbt, items); return super.writeNbt(nbt); } }
从物品栏(或任何物品栏)中提取和放入
我们覆盖方块类中的 `onUse` 行为以从我们的物品栏中加入和提取物品。注意这也可以对任何 Inventory
实例完成,不仅是我们自己的(例如,也因此可以对箱子方块做同样的事)。首先我们处理第一个槽位,如果是空的。玩家如果拿着物品,则会将拿着的物品放入。物品进入第一个槽位,如果是空的,或者进入第二个槽位,如果第一个是空的,或者如果第二个是空的,我们则会输出与物品栏有关的信息。注意我们将 ItemStack
插入物品栏时调用 copy()
,这样不会随着玩家的 ItemStack
而被破坏。
public class ExampleBlock extends Block implements BlockEntityProvider { [...] @Override public boolean activate(BlockState blockState, World world, BlockPos blockPos, PlayerEntity player, Hand hand, BlockHitResult blockHitResult) { if (world.isClient) return true; Inventory blockEntity = (Inventory) world.getBlockEntity(blockPos); if (!player.getStackInHand(hand).isEmpty()) { // 检查第一个打开的槽位是什么,并从玩家手中放入物品 if (blockEntity.getInvStack(0).isEmpty()) { // 将玩家手中的物品堆放入物品栏中 blockEntity.setInvStack(0, player.getStackInHand(hand).copy()); // 从玩家手中移除物品堆 player.getStackInHand(hand).setCount(0); } else if (blockEntity.getInvStack(1).isEmpty()) { blockEntity.setInvStack(1, player.getStackInHand(hand).copy()); player.getStackInHand(hand).setCount(0); } else { // 如果物品栏是满的,我们输出其内容 System.out.println("The first slot holds " + blockEntity.getInvStack(0) + " and the second slot holds " + blockEntity.getInvStack(1)); } } return true; } }
当玩家不持有物品时,我们将采取相反的行为。我们将从第二个槽位中取出项目,然后第二个中的第一个为空。如果第一个也是空的,我们将不做任何事情。
public class ExampleBlock extends Block implements BlockEntityProvider { [...] @Override public boolean activate(BlockState blockState, World world, BlockPos blockPos, PlayerEntity player, Hand hand, BlockHitResult blockHitResult) { ... if (!player.getStackInHand(hand).isEmpty()) { ... } else { // 如果玩家没有持有任何东西,我们依次将方块实体中的物品给予玩家 // 查找第一个有物品的槽位,并给予玩家 if (!blockEntity.getInvStack(1).isEmpty()) { // 给予玩家物品栏中的物品堆 player.inventory.offerOrDrop(world, blockEntity.getInvStack(1)); // Remove the stack from the inventory blockEntity.removeInvStack(1); } else if (!blockEntity.getInvStack(0).isEmpty()) { player.inventory.offerOrDrop(world, blockEntity.getInvStack(0)); blockEntity.removeInvStack(0); } } return true; } }
实现 SidedInventory 接口
如果你希望有基于与方块不同的面(漏斗或者其他模组)进行交互的不同逻辑,你可以实现 SidedInventory 接口。如果说你想使得方块不能从上侧插入,可以这样做:
public class DemoBlockEntity extends BlockEntity implements ImplementedInventory, SidedInventory { [...] @Override public int[] getInvAvailableSlots(Direction var1) { // Just return an array of all slots int[] result = new int[getItems().size()]; for (int i = 0; i < result.length; i++) { result[i] = i; } return result; } @Override public boolean canInsert(int slot, ItemStack stack, Direction direction) { return direction != Direction.UP; } @Override public boolean canExtract(int slot, ItemStack stack, Direction direction) { return true; } }