How do I store entities as a data on an Item

[TheRPGAdventurer]

Its an index right? for the position of which dragon UUID should I be selecting to input commands with?

[TheRPGAdventurer]

SO I have this in the guiDragonWhistle

	@Override
	protected void actionPerformed(GuiButton button) {
		if(dragon != null) {
		   byte previousState = dragon.getWhistleState();
		   dragon.come(button == come);
		   dragon.circle(button == circle);
		   dragon.follow(button == followFlying);
		   dragon.nothing(button == nothing);
		   byte controlState = dragon.getWhistleState();
		   if (controlState != previousState) {
					DragonMounts.NETWORK_WRAPPER
							.sendToServer(new MessageDragonWhistle(dragon.getEntityId(), controlState));
		    }
		} 
	}

How do I replace the nothing value, basicaaly the default one, the one with no commands. Can I just easily insert something like a null or false value?

[TheRPGAdventurer]

package com.TheRPGAdventurer.ROTD.client.items;

import java.util.List;
import java.util.UUID;

import javax.annotation.Nullable;

import com.TheRPGAdventurer.ROTD.DragonMounts;
import com.TheRPGAdventurer.ROTD.server.entity.EntityTameableDragon;
import com.TheRPGAdventurer.ROTD.util.DMUtils;

import net.minecraft.client.util.ITooltipFlag;
import net.minecraft.entity.Entity;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.nbt.NBTTagByte;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.nbt.NBTTagList;
import net.minecraft.nbt.NBTUtil;
import net.minecraft.util.ActionResult;
import net.minecraft.util.EnumActionResult;
import net.minecraft.util.EnumHand;
import net.minecraft.util.ResourceLocation;
import net.minecraft.util.text.TextComponentString;
import net.minecraft.world.World;
import net.minecraft.world.WorldServer;
import net.minecraftforge.common.WorldWorkerManager;
import net.minecraftforge.common.util.Constants;
import net.minecraftforge.fml.relauncher.Side;
import net.minecraftforge.fml.relauncher.SideOnly;

public class ItemDragonWhistle extends Item {

	// private final MessageDragonWhistle dcw = new MessageDragonWhistle();
	// private List<EntityTameableDragon> dragons = new ArrayList();
	// EntityTameableDragon dragon;
	private byte oldIndex;

	public ItemDragonWhistle() {
		this.setUnlocalizedName("dragon_whistle");
		this.setRegistryName(new ResourceLocation(DragonMounts.MODID, "dragon_whistle"));
		this.setMaxStackSize(1);
		this.setCreativeTab(DragonMounts.TAB);
	}

	@Override
	@SideOnly(Side.CLIENT)
	public void addInformation(ItemStack stack, @Nullable World worldIn, List<String> tooltip, ITooltipFlag flagIn) {
//		tooltip.add(StatCollector.translateToLocal(dragon.toString()));
	}

	@Override
	public ActionResult<ItemStack> onItemRightClick(World worldIn, EntityPlayer player, EnumHand hand) {
		ItemStack stack = player.getHeldItem(hand);

		int i = player.dimension;
        
        if(worldIn instanceof WorldServer) {
           WorldServer worldServer = (WorldServer) worldIn;
		   EntityTameableDragon dragon = (EntityTameableDragon) worldServer.getEntityFromUuid(stack.getTagCompound().getUniqueId("dragons"));
		   if (player.isSneaking() && stack.hasTagCompound()) {
			   byte oldIndex = stack.getTagCompound().getByte("dragons");
			   byte newIndex = (byte) ((oldIndex + 1) % Math.min(3, stack.getTagCompound().getSize()));
			   stack.getTagCompound().setByte("dragons", newIndex);	
			   DMUtils.getLogger().info("Dragon is" + dragon.getDisplayName().toString());
			   player.sendStatusMessage(new TextComponentString("whistle.controlling:" + dragon.getDisplayName().toString() + "" +dragon.getUniqueID().toString()), true); 
			}
        }
		
        if (!player.isSneaking() && stack.hasTagCompound()) {
			if (worldIn.isRemote) {
				DragonMounts.proxy.openDragonWhistleGui(stack.getTagCompound().getUniqueId("dragons"),
						new ItemStack(this), worldIn);
				return new ActionResult<ItemStack>(EnumActionResult.SUCCESS, stack);
			}
		} else if(!stack.hasTagCompound()) {
			    player.sendStatusMessage(new TextComponentString("whistle.empty"), true);
		        return new ActionResult<ItemStack>(EnumActionResult.FAIL, stack);
		}
        
		return new ActionResult<ItemStack>(EnumActionResult.FAIL, stack);

	}

	@Override
	public boolean onLeftClickEntity(ItemStack stack, EntityPlayer player, Entity target) {
		if (target instanceof EntityTameableDragon) {
			EntityTameableDragon dragon = (EntityTameableDragon) target;
			if (dragon.isTamedFor(player)) {
				NBTTagCompound nbt = new NBTTagCompound();
	//			NBTTagList nbtList; 

				if (stack.hasTagCompound()) {
					nbt = stack.getTagCompound();
				} else {
					stack.setTagCompound(nbt);
				}

				if (nbt.hasKey("dragons") && stack.getTagCompound().getSize() <= 3) { // I got confused because VoidWalker is mentioning NBTTagList and Im tempted use it
					UUID uuid = dragon.getUniqueID();
					nbt.setTag("dragons", NBTUtil.createUUIDTag(uuid)); // is storing for the dragon in here enough?
				} else {
					player.sendStatusMessage(new TextComponentString("whistle.limit"), true);
				}
			} else {
                player.sendStatusMessage(new TextComponentString("dragon.notOwned"), true);
			}
			return true;
		} else {
			return false;
		}
	}
}

1. is stack.gettagcompound.setByte("dragons", newIndex) should I use to get the index of collected dragons? I get an error called: Caused by: java.lang.ArithmeticException: / by zero

2. I thinks something is missing I ge

Edited December 20, 2018 by diesieben07
syntax highlighting

[TheRPGAdventurer]

13 hours ago, diesieben07 said:

Ahem:

 

Your code does not make much sense. You are treating the dragons NBT key both as a byte and also as a single UUID. You need a separate key for the index and the list of UUIDs.

If the oneo f the dragon is dead, how do I remove its index?

[TheRPGAdventurer]

On 12/18/2018 at 6:59 PM, V0idWa1k3r said:

Eiher name your tags dragon_0, dragon_1, etc. or store them in an NBTTagList.

 

This is the only one that I do not understand. Dont kno how to use NBTTagList, What tag dragn_0, I though there was only 2 NBT's. the "dragon"  for the dragon and "byte" for the selection

[TheRPGAdventurer]

Ok I learned a ne thing, I used dragonEntityID instead of the UUID