I'm currently working on an item(called ressurection amulet) that the player can apply onto tamable animals. When these animals die they drop that item which then allows the player to ressurect them. But when I try to shrink the ItemStack the player's inventory doesn't update accordingly.

The following lines are printed to the console when running the code below:
1: "1 ressurection_amulet"
2: "0 air"
3: player inventory that still contains the ressurection amulet

	@Override
	public InteractionResult useOn(UseOnContext context) {
		System.out.println("use");
		
		if (ressurectEntity(context.getLevel(), context.getClickLocation().add(new Vec3(0, 1, 0)), context.getItemInHand()))
		{
			System.out.println("ressurect");
			System.out.println(context.getItemInHand()); // 1
			context.getItemInHand().shrink(1);
			System.out.println(context.getItemInHand()); // 2
			System.out.println(context.getPlayer().getInventory().items); // 3
			return InteractionResult.CONSUME;
		}
		else
		{
			return InteractionResult.FAIL;
		}
	}
	
	@Override
	public InteractionResult interactLivingEntity(ItemStack itemStack, Player player, LivingEntity entity, InteractionHand hand) {
		System.out.println("entity interact");
		
		if (!(entity instanceof TamableAnimal)) return InteractionResult.FAIL; //change
		
		entity.addTag("ressurection_amulet_applied");
		System.out.println(itemStack); // 1
		itemStack.shrink(1);
		System.out.println(itemStack); // 2
		System.out.println(player.getInventory().items); // 3
		
		return InteractionResult.CONSUME;
	}

 

Look at how BoneMealItem uses isClientSide and InteractionResult.sidedSuccess().

I took a look at it and adjusted my code accordingly. But it still doesn't work correctly. Now I the 3rd print gives me the inventory without the item (as it should be) but the player's GUI doesn't update. Additionaly when I use another ressurection amulet it's 3rd print shows the item again:

use of amulet in 1st slot: "[0 air, 1 amulet_of_ressurection, 1 air, 1 air, 1 air, 1 air, 1 amulet_of_ressurection, 1 netherite_sword, 1 wolf_spawn_egg]"
use of amulet in 2nd slot: "[1 amulet_of_ressurection, 0 air, 1 air, 1 air, 1 air, 1 air, 1 amulet_of_ressurection, 1 netherite_sword, 1 wolf_spawn_egg]"

 

	@Override
	public InteractionResult useOn(UseOnContext context) {
		Level level = context.getLevel();
		
		if (level instanceof ServerLevel && !level.isClientSide) {
			System.out.println(context.getItemInHand()); // 1
			context.getItemInHand().shrink(1);
			System.out.println(context.getItemInHand()); // 2
			System.out.println(context.getPlayer().getInventory().items); // 3
		}
		
		return InteractionResult.sidedSuccess(level.isClientSide);
	}

 

Except for the double checking of whether it is on the server, I don't see anything wrong with that code.

I tried it and it works properly for me.

You need to put an example on github that reproduces the problem so we can see everything in context and try it for ourselves if necessary.

Edited December 3, 20222 yr by warjort

Here you go: https://github.com/TheScaryParrot/mc-forge-modding-itemstack-problem/tree/main/src/main

The code can be found at: src/main/java/io/github/thescaryparrot/darkcenturies/newstuff/items/RessurectionAmulet.java & TestItem.java

Maybe I am misunderstanding the problem, but the code in that github repository works fine for me?

You are referring to the useOn() block code?

Quote

[15:09:35] [Render thread/INFO] [minecraft/ChatComponent]: [System] [CHAT] Gave 2 [item.darkcenturies.amulet_of_ressurection] to Dev
1 amulet_of_ressurection
0 air
[0 air, 1 amulet_of_ressurection, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air]
1 amulet_of_ressurection
0 air
[0 air, 0 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air, 1 air]
 

 

You're understanding absolutly fine. Seems like a me problem then.

I also tried building the mod and I still get the same result (item not disappearing from inventory).

I'll take a look at it the following days maybe my MC is broken? In the meantime thank you very much for your help!

OMG I found the problem. I was testing in creative and not survival mode. Obviously items aren't consumed in creative.