Creating chest with items

[evjeny.23]

I need to spawn a chest with some items. I have these variables:

PlayerEntity player; 
World world; 
BlockPos pos; 
ItemEntity[] items;
// they are assigned, but I don't show the assignments here.

I need to create a chest (or a barrel, or a shulker box) in world "world" at position "pos" with items "items". How can I do that?

P.S. my minecraft forge version is 1.15.2.

[Animefan8888]

  On 4/6/2020 at 11:14 PM, evjeny.23 said:

I need to create a chest (or a barrel, or a shulker box) in world "world" at position "pos" with items "items". How can I do that?

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World::setBlockState(pos, THE_BLOCK_STATE_YOU_WANT)

This will place the block and the TileEntity into the world.

World::getTileEntity(pos)

This will get the TileEntity at the BlockPos pos.
Use the CapabilityItemHandler.ITEM_HANDLER_CAPABILITY to add the items to it.

[evjeny.23]

  On 4/6/2020 at 11:22 PM, Animefan8888 said:

Use the CapabilityItemHandler.ITEM_HANDLER_CAPABILITY to add the items to it.

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How exactly do I need to use it?

[Animefan8888]

  On 4/7/2020 at 12:05 AM, evjeny.23 said:

How exactly do I need to use it?

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Read the documentation on capabilities here.

[evjeny.23]

  On 4/7/2020 at 12:07 AM, Animefan8888 said:

Read the documentation on capabilities here.

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I have written the following code based on a related question:

final IItemHandler[] nowHandler = new IItemHandler[1];
world.setBlockState(pos, Blocks.CHEST.getDefaultState());
TileEntity chestTileEntity = worldIn.getTileEntity(pos);
IItemHandler itemHandler;
nowHandler[0] = null;
chestTileEntity.getCapability(CapabilityItemHandler.ITEM_HANDLER_CAPABILITY).ifPresent(new NonNullConsumer <IItemHandler>() {
  @Override
  public void accept(IItemHandler ih) {
  	nowHandler[0] = ih;
  }
});
while (nowHandler[0] == null) {};
itemhandler = nowHandler[0];
itemHandler.insertItem(1, new ItemStack(Items.SOME_ITEM, 1), false); // also I don't understand what "bool simulate" does

But it doesn't work. Chest spawns, but there are no items in it. (There are no errors in LOG).

[Animefan8888]

  On 4/7/2020 at 12:15 AM, evjeny.23 said:

// also I don't understand what "bool simulate" does

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If simulate is true it only simulates adding the ItemStack to the IItemHandler.

  On 4/7/2020 at 12:15 AM, evjeny.23 said:

final IItemHandler[] nowHandler = new IItemHandler[1];

IItemHandler itemHandler;

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Why?

  On 4/7/2020 at 12:15 AM, evjeny.23 said:

itemHandler.insertItem(1, new ItemStack(Items.SOME_ITEM, 1), false); // also I don't understand what "bool simulate" does

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Why not just put this in the accept function?

 

  On 4/7/2020 at 12:15 AM, evjeny.23 said:

But it doesn't work. Chest spawns, but there are no items in it. (There are no errors in LOG).

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Where is this code being called? Post all of it,

[evjeny.23]

  On 4/7/2020 at 12:25 AM, Animefan8888 said:

Where is this code being called? Post all of it,

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    @SubscribeEvent
    public void onLivingEntityDrops(LivingDropsEvent event) {
    	LOGGER.info("DROP");
    	if (!(event.getEntityLiving() instanceof PlayerEntity)) return;
    	BlockPos bedPos;
    	try {
    		bedPos = ((PlayerEntity)event.getEntityLiving()).getBedPosition().get();
    	} catch (NoSuchElementException e) {
    		bedPos = new BlockPos(0, event.getEntityLiving().getPosition().getY(), 0);
    	}
    	World worldIn = event.getEntityLiving().getEntityWorld();
    	final IItemHandler[] nowHandler = new IItemHandler[1];
    	worldIn.setBlockState(bedPos, Blocks.BARREL.getDefaultState());
    	TileEntity barrelContainer = worldIn.getTileEntity(bedPos);
    	IItemHandler itemhandler;
    	nowHandler[0] = null;
    	barrelContainer.getCapability(CapabilityItemHandler.ITEM_HANDLER_CAPABILITY).ifPresent(new NonNullConsumer <IItemHandler>() {
    		@Override
    		public void accept(IItemHandler ih) {
    			nowHandler[0] = ih;
    		}
    	});
    	while (nowHandler[0] == null) {};
    	itemhandler = nowHandler[0];
    	int slot = 0;
    	for (ItemEntity item : event.getDrops()) {
    		LOGGER.info("drop");
    		ItemStack leftItemsStack = itemhandler.insertItem(slot, item.getItem().copy(), false);
    		if (!leftItemsStack.equals(ItemStack.EMPTY)) {
    			bedPos = bedPos.north();
    			worldIn.setBlockState(bedPos, Blocks.BARREL.getDefaultState());
    			barrelContainer = worldIn.getTileEntity(bedPos);
    			itemhandler = nowHandler[0];
    			slot = 0;
    		}
    		slot++;
    	}
    }

Now it raises NullPointerException.

Edited April 7, 2020 by evjeny.23

[Animefan8888]

  On 4/7/2020 at 12:30 AM, evjeny.23 said:

Now it raises NullPointerException.

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I've got a couple of things to say.

 

First and foremost: Please learn Java before trying to make a Minecraft Forge mod. Java itself is hard to learn let alone trying to learn an extensive API like Forge.

 

Secondly: If you crash or an exception is thrown there is a lot of useful information inside the stacktrace. You should read it. If you don't know what it means google it. If that doesn't supply you with answers/enough information post the error.

 

Thirdly:

  On 4/7/2020 at 12:25 AM, Animefan8888 said:

  On 4/7/2020 at 12:15 AM, evjeny.23 said:

final IItemHandler[] nowHandler = new IItemHandler[1];

IItemHandler itemHandler;

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Why?

  On 4/7/2020 at 12:15 AM, evjeny.23 said:

itemHandler.insertItem(1, new ItemStack(Items.SOME_ITEM, 1), false); // also I don't understand what "bool simulate" does

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Why not just put this in the accept function?

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