I've been working on a gui for my upcoming mod, and I'm having a few problems with client-server syncing stuff.

I'll explain exactly what I'm trying to accomplish. A user hits a button in the gui, which does some neat java stuff and sends a packet off to the server, which then writes some NBT data to an ItemStack. In it's current state, it's half-working. The server knows about everything that's happened, but the clients don't, and I don't know how to go about telling them.

 

What should I do?

 

Here's my Tile Entity source incase you need it.

 

package net.minecraft.src.sorcery;

import net.minecraft.src.*;
import net.minecraft.src.sorcery.base.*;
import net.minecraft.src.sorcery.network.PacketHandler;

import java.util.Random;

import com.google.common.io.ByteArrayDataInput;

public class TileEntityWandCrafting extends TileEntityBasic implements IInventory
{
    private ItemStack[] items = new ItemStack[4];

    public int getSizeInventory()
    {
        return 4;
    }
    
    public void handlePacket(NetworkManager network, Packet250CustomPayload packet, EntityPlayer player, ByteArrayDataInput data)
    {
    	int mod1 = data.readInt();
    	int mod2 = data.readInt();
    	int mod3 = data.readInt();
    	craftWand(mod1, mod2, mod3);
    }
    
    public void getModifiers()
    {
    	int[] wandMods = new int[3];
    	wandMods[0] = 0;
    	wandMods[1] = 0;
    	wandMods[2] = 0;
    	
    	ItemStack wand = items[3];
    	ItemStack crystal = items[2];
    	ItemStack core1 = items[0];
    	ItemStack core2 = items[1];
    	
    	if(wand != null && crystal !=null)
    	{
    		if(wand.itemID == (new ItemStack(Sorcery.wand)).itemID && crystal.itemID == (new ItemStack(Sorcery.battery, 1, 0)).itemID && crystal.getItemDamage() == 0)
    		{
    			int j = 0;
    			
    			for(EnumWandMods mods : EnumWandMods.values())
    			{
    				if(core1 != null)
    				{
    					if(core1.itemID == EnumWandMods.values()[j].item.itemID)
    					{
    						wandMods[0] = EnumWandMods.values()[j].modID;
   
    					}
    				}
    				
    				if(core2 != null)
    				{
    					if(core2.itemID == EnumWandMods.values()[j].item.itemID)
    					{
    						wandMods[1] = EnumWandMods.values()[j].modID;
   
    					}
    				}
    				j = j+1;
    			}	
    		}
            PacketHandler.getInstance().sendTEPacketToServer(this, "Sorcery", wandMods[0], wandMods[1], wandMods[2]);
    	}
    }
    
    public void craftWand(int mod1, int mod2, int mod3)
    {
    	EnumWandMods[] wandMods = new EnumWandMods[3];
    	wandMods[0] = SorceryHelper.getInstance().getModFromInt(mod1);
    	wandMods[1] = SorceryHelper.getInstance().getModFromInt(mod2);
    	wandMods[2] = SorceryHelper.getInstance().getModFromInt(mod3);
    	
    	ItemStack wand = items[3];
    	ItemStack crystal = items[2];
    	ItemStack core1 = items[0];
    	ItemStack core2 = items[1];
    	
    	if(core1 != null)
    	{
    		decrStackSize(0, 1);
    	}
    	
    	if(core2 != null)
    	{
    		decrStackSize(1, 1);
    	}
    	
    	decrStackSize(2, 1);
    	
	wand.setTagCompound(new NBTTagCompound());
	wand.stackTagCompound.setTag("mods", new NBTTagList("mods"));
	NBTTagList list = (NBTTagList)wand.stackTagCompound.getTag("mods");

	for(int i = 0; i < wandMods.length; i++)
	{
		NBTTagCompound tag = new NBTTagCompound();
		tag.setInteger("ID", wandMods[i].modID);
		tag.setBoolean("Positive", wandMods[i].pos);
		list.appendTag(tag);
	}
    	
    }
    
    public ItemStack getStackInSlot(int par1)
    {
        return this.items[par1];
    }

    public ItemStack decrStackSize(int par1, int par2)
    {
        if (this.items[par1] != null)
        {
            ItemStack var3;

            if (this.items[par1].stackSize <= par2)
            {
                var3 = this.items[par1];
                this.items[par1] = null;
                this.onInventoryChanged();
                return var3;
            }
            else
            {
                var3 = this.items[par1].splitStack(par2);

                if (this.items[par1].stackSize == 0)
                {
                    this.items[par1] = null;
                }

                this.onInventoryChanged();
                return var3;
            }
        }
        else
        {
            return null;
        }
    }

    public ItemStack getStackInSlotOnClosing(int par1)
    {
        if (this.items[par1] != null)
        {
            ItemStack var2 = this.items[par1];
            this.items[par1] = null;
            return var2;
        }
        else
        {
            return null;
        }
    }

    public void setInventorySlotContents(int par1, ItemStack par2ItemStack)
    {
        this.items[par1] = par2ItemStack;

        if (par2ItemStack != null && par2ItemStack.stackSize > this.getInventoryStackLimit())
        {
            par2ItemStack.stackSize = this.getInventoryStackLimit();
        }

        this.onInventoryChanged();
    }

    public int func_70360_a(ItemStack par1ItemStack)
    {
        for (int var2 = 0; var2 < this.items.length; ++var2)
        {
            if (this.items[var2] == null || this.items[var2].itemID == 0)
            {
                this.items[var2] = par1ItemStack;
                return var2;
            }
        }

        return -1;
    }

    public String getInvName()
    {
        return "container.wandcrafting";
    }

    public void readFromNBT(NBTTagCompound par1NBTTagCompound)
    {
        super.readFromNBT(par1NBTTagCompound);
        NBTTagList var2 = par1NBTTagCompound.getTagList("Items");
        this.items = new ItemStack[this.getSizeInventory()];

        for (int var3 = 0; var3 < var2.tagCount(); ++var3)
        {
            NBTTagCompound var4 = (NBTTagCompound)var2.tagAt(var3);
            int var5 = var4.getByte("Slot") & 255;

            if (var5 >= 0 && var5 < this.items.length)
            {
                this.items[var5] = ItemStack.loadItemStackFromNBT(var4);
            }
        }
    }

    public void writeToNBT(NBTTagCompound par1NBTTagCompound)
    {
        super.writeToNBT(par1NBTTagCompound);
        NBTTagList var2 = new NBTTagList();

        for (int var3 = 0; var3 < this.items.length; ++var3)
        {
            if (this.items[var3] != null)
            {
                NBTTagCompound var4 = new NBTTagCompound();
                var4.setByte("Slot", (byte)var3);
                this.items[var3].writeToNBT(var4);
                var2.appendTag(var4);
            }
        }

        par1NBTTagCompound.setTag("Items", var2);
    }

    public int getInventoryStackLimit()
    {
        return 64;
    }

    public boolean isUseableByPlayer(EntityPlayer par1EntityPlayer)
    {
        return this.worldObj.getBlockTileEntity(this.xCoord, this.yCoord, this.zCoord) != this ? false : par1EntityPlayer.getDistanceSq((double)this.xCoord + 0.5D, (double)this.yCoord + 0.5D, (double)this.zCoord + 0.5D) <= 64.0D;
    }

    public void openChest() {}

    public void closeChest() {}
    
    @Override
    public void onInventoryChanged()
    {
    	
    }
}

 

Tell me if you need to see more.

 

If I haven't explained what I'm trying to achieve particularly well, just say so and I'll try and make it clearer. Also, feel free to yell at me for being a noob.

Seems to me that after you edit the item on the server side

you need to send a packet to the client telling it that the item in the slot has changed...

Oh I wonder if thats ever been done before....