Hi, when i use this

player.inventory.decrStackSize(player.inventory.currentItem, 64);

or this

player.inventory.setInventorySlotContents(player.inventory.currentItem, (ItemStack)null);

to remove Item from players inventory it comes back in any ideas?

Are you doing it client side or server side?

In onBlockActivated method of my block class.

In onBlockActivated method of my block class.

That method is called on both sides, so theoretically it should work, but even still, you would only want to set inventory contents on the server side, i.e. when the world is NOT remote.

 

Also, without seeing your code, it's possible you are doing something that forces it to be done on the client side. Show your code.

I think i do becose i am summoning item but it is just ghost item.

@Override
    public boolean onBlockActivated(World world, int x, int y, int z, EntityPlayer player, int metadata, float what, float these, float are) {
	if (cooldown > 0) {
		return false;
	}
        TileEntityInfuser tileEntity = (TileEntityInfuser)world.getTileEntity(x, y, z);
        if (tileEntity == null) {
            return false;
        }
        ItemStack heldItem = player.inventory.getCurrentItem();
        if (heldItem == null) {
         if (player.isSneaking()) {
        	ChatUtils.newChatMessage(player, "Stored NatureFlux: " + String.valueOf(storedNF));
        } else if (!player.isSneaking() && tileEntity.getStackInSlot(0) != (ItemStack)null) {
        	
        	ItemStack item = tileEntity.getStackInSlot(0);
        	
        	float rx = rand.nextFloat() * 0.8F + 0.1F;
            float ry = rand.nextFloat() * 0.8F + 0.1F;
            float rz = rand.nextFloat() * 0.8F + 0.1F;

            EntityItem entityItem = new EntityItem(world,
                            x + rx, y + ry, z + rz,
                            new ItemStack(item.getItem(), item.stackSize, item.getItemDamage()));

            if (item.hasTagCompound()) {
                    entityItem.getEntityItem().setTagCompound((NBTTagCompound) item.getTagCompound().copy());
            }

            float factor = 0.05F;
            entityItem.motionX = rand.nextGaussian() * factor;
            entityItem.motionY = rand.nextGaussian() * factor + 0.2F;
            entityItem.motionZ = rand.nextGaussian() * factor;
            world.spawnEntityInWorld(entityItem);
            
            tileEntity.setInventorySlotContents(0, (ItemStack)null);
        }
        } else {
        	if (player.isSneaking() && heldItem.getItem().getUnlocalizedName() == NFItems.transmutator.getUnlocalizedName()) {
        	//Playrutils.removeItem(player, heldItem);
        	tileEntity.setInventorySlotContents(0, heldItem);
        	player.inventory.decrStackSize(player.inventory.currentItem, 64);
        	//player.inventory.setInventorySlotContents(player.inventory.currentItem, (ItemStack)null);
        } else if (!player.isSneaking() && tileEntity.getStackInSlot(0) != (ItemStack)null) {
        
        	ItemStack item = tileEntity.getStackInSlot(0);
        	
        	System.out.println(item.getItem().getUnlocalizedName(item));
        	
        	float rx = rand.nextFloat() * 0.8F + 0.1F;
            float ry = rand.nextFloat() * 0.8F + 0.1F;
            float rz = rand.nextFloat() * 0.8F + 0.1F;

            EntityItem entityItem = new EntityItem(world,
                            x + rx, y + ry, z + rz,
                            new ItemStack(item.getItem(), item.stackSize, item.getItemDamage()));

            if (item.hasTagCompound()) {
                    entityItem.getEntityItem().setTagCompound((NBTTagCompound) item.getTagCompound().copy());
            }

            float factor = 0.05F;
            entityItem.motionX = rand.nextGaussian() * factor;
            entityItem.motionY = rand.nextGaussian() * factor + 0.2F;
            entityItem.motionZ = rand.nextGaussian() * factor;
            world.spawnEntityInWorld(entityItem);
            
            //tileEntity.setInventorySlotContents(0, (ItemStack)null);
        }
        }
        cooldown = 10;
        return true;
    }

I tried adding

world.isRemote

to this if

if (tileEntity == null) {
            return false;
        }

and it simply does nothing. That method is not executed on server side.

heldItem.getItem().getUnlocalizedName() == NFItems.transmutator.getUnlocalizedName()

No. For one, you typically do not want to compare Strings using the == operator, though it would probably work in this case. Secondly, why are you comparing the unlocalized name, rather than the item instance?

heldItem.getItem() == NFItems.transmutator

That is much clearer, more efficient, and the standard way everyone checks to see if an ItemStack contains the item they want.

 

Also, it looks like you are storing local variables in your Block class, specifically 'cooldown' - there is only ever ONE instance of your block, so all of those blocks in the entire world will have the same value for cooldown all the time. Is that really what you want? If you want independent cooldowns, you need to store them either as metadata (similar to crop growth stages) or in a TileEntity.

 

Finally, setting the held item to null is easier using the #setCurrentItemOrArmor method:

player.setCurrentItemOrArmor(0, null);

However, I suggest you redo your code - start out simple, make sure it works, and add complexity one piece at a time, otherwise you have no idea what is not working.