How to create Item Entity

Plugins Plugin Development
1

I’m trying to spawn an item entity into the world with a given item stack, location, and world.

I was reading this post here: [SOLVED] Creating an Item Entity

And I tried to follow it as best I could, but it seems things have changed a little bit since then. Here is the code I’ve written:

@Override
public void spawnItem( ItemStack itemStack, Location<World> spawnLocation, World world )
{
    Optional<Entity> itemEntity = world.createEntity( EntityTypes.ITEM, spawnLocation.getPosition() );

    if ( itemEntity.isPresent() )
    {
        Item items = (Item) itemEntity.get();
        Optional<RepresentedItemData> itemData = items.getItemData().fill( itemStack );

        if ( itemData.isPresent() )
        {
            items.offer( itemData.get() );

            world.spawnEntity(
                items, Cause.of( EntitySpawnCause.builder().entity( items ).type( SpawnTypes.PLUGIN ).build() ) );
        }
        else
        {
            logger.warn( "Unable to create item data for itemstack {}", itemStack );
        }
    }
    else
    {
        logger.warn( "Unable to spawn item for itemstack {}", itemStack );
    }
}

Whenever I run this I get:
“Unable to create item data for itemstack 1xtile.log@2”

Anyone have any ideas what I’m doing wrong?

2

Try just offering the entity the itemstack.

entity.offer(Keys.REPRESENTED_ITEM, itemStack)

3

Now I have:

@Override
public void spawnItem( ItemStack itemStack, Location<World> spawnLocation, World world )
{
    Optional<Entity> itemEntity = world.createEntity( EntityTypes.ITEM, spawnLocation.getPosition() );

    if ( itemEntity.isPresent() )
    {
        Item items = (Item) itemEntity.get();

        items.offer( Keys.REPRESENTED_ITEM, itemStack.createSnapshot() );

        world.spawnEntity(
            items, Cause.of( EntitySpawnCause.builder().entity( items ).type( SpawnTypes.PLUGIN ).build() ) );
    }
    else
    {
        logger.warn( "Unable to spawn item for itemstack {}", itemStack );
    }
}

It works until up to the part where it tries to spawn the entity, where I get the following exception:

Could not pass ChangeBlockEvent$Break$Impl to Plugin{id=treebreaker, name=Sodium labs’ Treebreaker, version=0.1}
java.lang.IllegalArgumentException: Could not find a Supplier for the provided class: org.spongepowered.api.event.cause.entity.spawn.EntitySpawnCause.Builder
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:125) ~[minecraft_server.1.8.jar:?]
at org.spongepowered.common.registry.SpongeGameRegistry.createBuilder(SpongeGameRegistry.java:249) ~[SpongeGameRegistry.class:1.8-3.0.0-BETA-129]
at org.spongepowered.api.event.cause.entity.spawn.EntitySpawnCause.builder(EntitySpawnCause.java:34) ~[EntitySpawnCause.class:1.8-3.0.0-BETA-129]

4

I was able to fix this by passing “this” into the cause.

world.spawnEntity( items, Cause.of( this ) );

But, I think this runs contrary to the docs here: https://docs.spongepowered.org/en/plugin/entities/spawning.html

5

Thanks for letting us know. Could I ask of you the Sponge Version you encountered this error with?

I will investigate whether the docs are at fault or it was a problem with the version you used. See the GitHub issue I created for updates / findings.

6

Updated the github issue

7

It’s an issue that the SpawnCauses have not been implemented and aren’t in use in any of the spawn events, this will be fixed sooner than later.