Hello! I am rewriting my Transmutation mod, and I still cannot figure out how to leave an item in the craftMatrix. According to this post, I am supposed to call

matrix.setInventorySlotContents(int i, ItemStack k)

, but when I do so, the item does not stay in the crafting grid!

 

My event subscription method is as follows:

 

public class CraftingHandler
{
    @SubscribeEvent
    public void ItemCraftedEvent(PlayerEvent.ItemCraftedEvent e)
    {
        Transmutation.logger.info("Attempting to craft");
        for (int i = 0; i < e.craftMatrix.getSizeInventory(); i++)
        {
            if (e.craftMatrix.getStackInSlot(i) == null) continue;
            if (e.craftMatrix.getStackInSlot(i).getItem() == Recipes.tStone)
            {
                Transmutation.logger.info("Crafting with a transmutation stone");
                ItemStack stone = e.craftMatrix.getStackInSlot(i);
                if (!stone.hasTagCompound()) return; // debug stone
                Transmutation.logger.info("Crafting complete");
                stone.getTagCompound().setInteger("uses", stone.getTagCompound().getInteger("uses")-1);
                if (stone.getTagCompound().getInteger("uses") < 1) stone = new ItemStack(Blocks.air);
                else
                {
                    Transmutation.logger.info("Attempting to leave the itemstack in the matrix..");
                    e.craftMatrix.setInventorySlotContents(i, stone);
                }
                return;
            }
        }
    }
}

 

As you can see, I am calling

 e.craftMatrix.setInventorySlotContents(i, stone);

but the item does not stay in the crafting grid. How can I fix this?

 

 

On a side note, is there a way to "remove" an itemstack from the crafting grid? I don't know if setting it to an air block is something that's good or not.

It seems that when I craft with the item (i set the container item to itself) that the NBT tags are erased, but the item stays in the crafting grid. How can I edit the NBT while crafting?

There is ItemStack version of getItemStack in the Item class:

    public ItemStack getContainerItem(ItemStack itemStack)

You can use it to migrate/modify NBT of the container item.

Where do I edit the nbt while crafting? The craft event?

 

Edit:

 

Never mind! I figured it out myself! Apparently you override the getContainerItem method and do what you wish with it. Here's my end result:

    @Override
    public ItemStack getContainerItem(ItemStack itemStack)
    {
        int uses = itemStack.getTagCompound().getInteger("uses")-1;
        String owner = itemStack.getTagCompound().getString("owner");
        if (uses < 1)
        {
            return null;
        }
        ItemStack cItem = new ItemStack(getContainerItem());
        cItem.setTagCompound(new NBTTagCompound());
        cItem.getTagCompound().setInteger("uses", uses);
        cItem.getTagCompound().setString("owner", owner);
        return cItem;
    }