I need to put an item in a menu cell.
I use something like this.

Spoiler

itemstack.getCapability(ForgeCapabilities.ITEM_HANDLER, null).ifPresent(capability -> {
        if(entity instanceof Player player){
          
		for(int i = 0; i < inventory.getContainerSize(); ++i) {
          
            itemStack = inventory.getItem(i);

            if(predicate.test(itemStack)){

                itemHandler.insertItem(0,itemStack,false);
                //inventory.removeItem(stack); 
                return;
            }
        }
        }
});

 

The problem is that the item is duplicated without removeItem. And with it, the object turns into AIR and does not work.
I have a menu, dragging to the slot works fine.

I'm sure I'm doing something wrong, can you please advise?

ICapability class

Spoiler

@Mod.EventBusSubscriber(Dist.CLIENT)
public class GunShot_Capability implements ICapabilitySerializable<CompoundTag> {
    @SubscribeEvent
    @OnlyIn(Dist.CLIENT)
    public static void onItemDropped(ItemTossEvent event) {
        if (event.getEntity().getItem().getItem() == ForgeModItems.AK47.get()) {
            if (Minecraft.getInstance().screen instanceof Gun_Screen) {
                Minecraft.getInstance().player.closeContainer();
            }
        }
    }

    private final LazyOptional<ItemStackHandler> inventory = LazyOptional.of(this::createItemHandler);

    @Override
    public <T> LazyOptional<T> getCapability(@Nonnull Capability<T> capability, @Nullable Direction side) {
        return capability == ForgeCapabilities.ITEM_HANDLER ? this.inventory.cast() : LazyOptional.empty();
    }

    @Override
    public CompoundTag serializeNBT() {
        return getItemHandler().serializeNBT();
    }

    @Override
    public void deserializeNBT(CompoundTag nbt) {
        getItemHandler().deserializeNBT(nbt);
    }

    private ItemStackHandler createItemHandler() {
        return new ItemStackHandler(9) {
            @Override
            public int getSlotLimit(int slot) {
                return 64;
            }

            @Override
            public boolean isItemValid(int slot, @Nonnull ItemStack stack) {
                return stack.getItem() != ForgeModItems.AK47.get();
            }

            @Override
            public void setSize(int size) {
            }
        };
    }

    private ItemStackHandler getItemHandler() {
        return inventory.orElseThrow(RuntimeException::new);
    }

}

 

(I can provide a class menu if needed)

Edited April 17, 20232 yr by Luckydel

I'm an idiot, this should be done on the server side, and I had the wrong validation.

Thanks to everyone who took the time.