I'm trying to make a Item with battery, so I use stack.damageItem() to damage the itemstack, but don't works.
Here's the register:
 

public static final RegistryObject<Item> REMOTE = ITEMS.register("remote", () -> new RemoteItem(new Item.Properties().group(ModItemGroup.LM_TAB)));

Here's the class of the item:
 

package me.foxware.lm.items;

import java.awt.Color;
import java.util.List;

import net.minecraft.client.util.ITooltipFlag;
import net.minecraft.entity.player.PlayerEntity;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.util.ActionResult;
import net.minecraft.util.Hand;
import net.minecraft.util.math.vector.Vector3d;
import net.minecraft.util.text.ITextComponent;
import net.minecraft.util.text.TranslationTextComponent;
import net.minecraft.world.World;

public class RemoteItem extends Item {
	public RemoteItem(Properties properties) {
		super(properties.maxDamage(100));
	}
	
	@Override
	public ActionResult<ItemStack> onItemRightClick(World world, PlayerEntity player, Hand hand) { 
		ItemStack item = player.getHeldItem(hand);
		
		if(!world.isRemote()) {
			if(item.getDamage() < item.getMaxDamage()) {
				Vector3d pos = player.getPositionVec();
				int X = Math.round((float) pos.x);
				int Y = Math.round((float) pos.y);
				int Z = Math.round((float) pos.z);
				
				item.damageItem(1, player, null);
				
				player.getCooldownTracker().setCooldown(this, 20);
				
				return ActionResult.resultSuccess(item);
			}
		}
		
		return ActionResult.resultFail(item);
	}
	
	@Override
	public boolean showDurabilityBar(ItemStack item) {
		if(item.getDamage() != 0)
			return true;
		return false;
	}
	@Override
	public int getRGBDurabilityForDisplay(ItemStack item) {
		return Color.CYAN.getRGB();
	}
	
	@Override
	public void addInformation(ItemStack item, World world, List<ITextComponent> tooltip, ITooltipFlag flag) {
		tooltip.add(new TranslationTextComponent("item.battery", Integer.toString(item.getMaxDamage() - item.getDamage())));
		
		super.addInformation(item, world, tooltip, flag);
	}
	
	@Override
	public int getItemStackLimit(ItemStack item) {
		return 1;
	}
}

 

5 hours ago, FoxWare said:

if(item.getDamage() < item.getMaxDamage()) {

This is pointless. If damage exceeds max damage, the item is broken and removed from your inventory.

7 hours ago, diesieben07 said:

That code should crash with a NullPointerException, you cannot pass null as onBroken.

 

Also:

Do not do this, translation keys ("item.battery" here) must include your ModID.

I "adjusted" my code but still don't work
 

package me.foxware.lm.items;

import java.awt.Color;
import java.util.List;

import net.minecraft.client.util.ITooltipFlag;
import net.minecraft.entity.player.PlayerEntity;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.util.ActionResult;
import net.minecraft.util.Hand;
import net.minecraft.util.math.vector.Vector3d;
import net.minecraft.util.text.ITextComponent;
import net.minecraft.util.text.TranslationTextComponent;
import net.minecraft.world.World;

public class RemoteItem extends Item {
	public RemoteItem(Properties properties) {
		super(properties.maxDamage(100));
	}
	
	@Override
	public ActionResult<ItemStack> onItemRightClick(World world, PlayerEntity player, Hand hand) { 
		ItemStack item = player.getHeldItem(hand);
		
		if(!world.isRemote()) {
			Vector3d pos = player.getPositionVec();
			int X = Math.round((float) pos.x);
			int Y = Math.round((float) pos.y);
			int Z = Math.round((float) pos.z);
			
			if(!player.abilities.isCreativeMode)
				item.damageItem(1, player, (damagePlayer) -> {damagePlayer.sendBreakAnimation(hand);});
			
			player.getCooldownTracker().setCooldown(this, 20);
			
			return ActionResult.resultSuccess(item);
		}
		
		return ActionResult.resultFail(item);
	}
	
	@Override
	public boolean showDurabilityBar(ItemStack item) {
		if(item.getDamage() != 0)
			return true;
		return false;
	}
	@Override
	public int getRGBDurabilityForDisplay(ItemStack item) {
		return Color.CYAN.getRGB();
	}
	
	@Override
	public void addInformation(ItemStack item, World world, List<ITextComponent> tooltip, ITooltipFlag flag) {
		if(item.getDamage() != 0)
			tooltip.add(new TranslationTextComponent("info.lm.battery", Integer.toString(item.getMaxDamage() - item.getDamage())));
		
		super.addInformation(item, world, tooltip, flag);
	}
	
	@Override
	public int getItemStackLimit(ItemStack item) {
		return 1;
	}
}

 

Make sure you are in survival mode when testing the item durability...also i believe there are some lines in your code that are redundant and not necessary, for example:

this check

if(!player.abilities.isCreativeMode)

and this override

	@Override
	public boolean showDurabilityBar(ItemStack item) {
		if(item.getDamage() != 0)
			return true;
		return false;
	}