how can I store an ItemStack in an NBT (it's for a tileEntity Inventory). The thing is, is that it's not with a GUI, so I don't want to implement IInventory. Can someone help?

https://github.com/Eternaldoom/Realms-of-Chaos/blob/1.8/com/eternaldoom/realmsofchaos/blocks/TileEntityDisplayCase.java

Does this allow for the ItemStack to be stored in the NBT of a TileEntity? It looks like you are just setting the NBT for the ItemStack.

In writeToNBT, I'm setting a compound tag with the data from the itemstack, and reading it in readFromNBT.

Why not use IInventory?

Even if you dont use a gui (which is totally missing the point of why people use IInventory) it is still the interface to use when creating a inventory.

it gives compatibility between mods and minecraft hoppers.

 

And if you look in the ItemStack class you can see that there are methods for writing an stack to NBT and methods for loading a stack from NBT.

Use those.

I found loadItemStackFromNBT() but what is the other function to get an NBT tag from an ItemStack?

 

I don't want to use IInventory mainly because I don't want my mod to be easily automatable with other mods because I will add my own kind of automation, I will probably add a single block to add compatibility instead of having to use autonomus activators (from Thermal Expansion) to interact with my blocks.

you can get the NBTTagCompound from an ItemStack with the getTagCompound() method. Note that by default an ItemStack does not have an NBTTagCompound so you need to check for that, and create one if null.

 

to load an ItemStack from nbt you need ItemStack.loadItemStackFromNBT(tag).

and to save an ItemStack to nbt you need stack.writeToNBT(tag).