If I have an IIventory TileEntity with several slots, and want only one of these to only take one item at a time(an Itemstack of size 1, that is), even if the item itself can be stacked, is that possible?

I did this in my Particle Deco Mod, here's the source:

https://github.com/SanAndreasP/Particle-Decoration-Mod

What I'm seeing in your source is that you make getStackSizeLimit return 1, but that will make all slots accept only 1 item per stack. What I'm thinking is an inventory where each slot can accept different max sizes.

That shouldn't be a problem. You can make a variable like

public int stackLimit = 64;

 

let it return in getSlotStackLimit:

    public int getSlotStackLimit()
    {
        return this.stackLimit;
    }

 

and make a constructor like:

public SlotCustom(ContainerCustom container, IInventory iinventory, int i, int j, int k, int l)
    {
        super(iinventory, i, j, k);
        field_40442_a = container;
        this.stackLimit = l;
    }

 

After all that, when you define the slots in the container, you can do this:

         addSlotToContainer(new SlotCustom(this, tileentity, 0, 47, 17, 4));
         addSlotToContainer(new PD_SlotCustom(this, tileentity, 1, 47, 52, 32));

 

The first would then take stacks with max. quantity 4, the second would take 32.

Oh, now I get it! I have to extend the Slot class! Thank you very much!