So I have a custom GUI with one row of 9 slots, and then a single slot above them all (which is supposed to act just like all the others, it's not an output). I loop through the row of 9 slots and add them to the container, which works fine. Then I add just the top slot and it's coordinates to the container. However, everytime I put an item in the top slot, it duplicates into the corresponding slot in the for loop. I know it's a logical error, but I'm not able to figure out how to fix it.

We can't help you if you don't provide us with code. Saying it's a logical error doesn't tell us or show us anything.

Sorry.

public CustomContainer(InventoryPlayer player, TestTileEntity tileEntity)
{
    this.tileEntity = tileEntity;

    // single slot
    this.addSlotToContainer(new Slot(tileEntity, 0, 80, 32));

    // row of 9
    for (int i = 0; i < 9; i++)
    {
        this.addSlotToContainer(new Slot(tileEntity, i, 8 + i * 18, 53));
    }


    /* Player Inventory and Hotbar */
    for (int y = 0; y < 3; y++)
    {
        for (int x = 0; x < 9; x++)
        {
            this.addSlotToContainer(new Slot(player, x + y * 9 + 9, 8 + x * 18, 84 + y * 18));
        }
    }

    for (int x = 0; x < 9; x++)
    {
        this.addSlotToContainer(new Slot(player, x, 8 + x * 18, 142));
    }
}

Edited January 8, 20196 yr by Siqhter

14 minutes ago, diesieben07 said:

You tell the "single slot" to use inventory index 0.

You also tell the first slot in the loop to use inventory index 0.

I know, that's why it duplicates the item because it's essentially the same slot. I don't know how to give it it's own index after looping through the first row. It's crashes the game with an out of bounds exception.

Thanks for the explanation. I got it working, but I don't quite understand what I did:

Spoiler

/* Single Slot */
this.addSlotToContainer(new Slot(tileEntity, 9, 80, 32));

/* Container Slots */
for (int i = 0; i < 9; i++)
{
    this.addSlotToContainer(new Slot(tileEntity, i, 8 + i * 18, 53));
}

The "single slot" index is 9. How does the "index" relate to the "actual" slot in which an item can be placed?

Edited January 8, 20196 yr by Siqhter

You have an arbitrary number of slots, you were assigning: 

slot 0 to single slot

slot 0 to container slot 0

slot 1 to container slot 1

slot 2 to container slot 2

...

slot 8 to container slot 8

 

now you are assigning

slot 9 to single slot

slot 0 to container slot 0

slot 1 to container slot 1

slot 2 to container slot 2

...

slot 8 to container slot 8

 

Previously you were assigning to slots to the same slot ID index, hence the duplicate slots

Edited January 8, 20196 yr by Cadiboo

13 minutes ago, Siqhter said:

/* Container Slots */

ID -> slotIndex, pretty much the same thing tho

In this (specific) case both need to be unique, which is what I meant 

Now when you told me to get rid of IInventory and use IItemHandler, is that because I'm using InventoryPlayer? How do switch it?

IInventory is legacy vanilla code, IItemHandler is forge’s intercompatible replacement

I guess I'm just unclear as to what I am supposed to replace with IItemHandler.

Edited January 9, 20196 yr by Siqhter

Edit:

I've done some research on IItemHandler and Capabilites, so rather, where am I supposed to implement using capabilities. The tileentity? And what needs to change in my container class so that I'm not implementing IInventory.

The tile entity should override the has/getCapability methods appropriately

replace everything from IInventory with the tile entities ItemstackHandler
You can see an example at

https://github.com/Cadiboo/WIPTech/blob/fb5883e9d76ef0361ec1ebbcb9c508611dd2ef6b/src/main/java/cadiboo/wiptech/tileentity/TileEntityModFurnace.java#L300-L340 

and 

https://github.com/Cadiboo/WIPTech/blob/fb5883e9d76ef0361ec1ebbcb9c508611dd2ef6b/src/main/java/cadiboo/wiptech/inventory/ContainerModFurnace.java 

Thank you, I'm taking a look at that. I'm wondering in your example, where do you set a display name for the container? Originally I had something like "container.name" after the createContainer method. But I believe that's from IInventory.

It gets drawn in drawGuiContainerForegroundLayer. You can draw it yourself 

9 hours ago, Cadiboo said:

It gets drawn in drawGuiContainerForegroundLayer. You can draw it yourself 

Ok, I didn't think of that. There's also a method called getDisplayName that works in the tileentity. Last question, I don't understand what's going on in your read and write to NBT methods. Mine aren't saving any items after quitting, but that's obvious because there's nothing in them. Not sure if I use set integer?