[1.9] Cycling through players inventory

[Daedalus]

I've been at this for a while now, and I try to not ask for help usually, but this time I'm at an impasse.

 

I've created the command "count" which I want to get the item that the player is currently holding, then count the amount of that item in the players inventory, then send the player a message with the amount of that item.

 

        ItemStack heldStack = player.inventory.getCurrentItem();

        if (heldStack != null)  {
            for (int i = 0; i < player.inventory.getSizeInventory(); i++) {
                ItemStack cycledStack = player.inventory.getStackInSlot(i);

                if (cycledStack.getItem().equals(heldStack)) {
                    itemCount = itemCount + cycledStack.stackSize;
                }
            }
        }

 

I'm still fairly new to Java, so I'm assuming it's some stupid mistake that I somehow made. I don't want to be spoonfed code, I want to learn, so if you guys could help me out by pointing me in the right direction, that would be awesome.

 

I apologize if I've forgotten anything in this post, please let me know if I have.

 

Thanks!

 

[coolAlias]

So what's the problem? Are you getting NullPointerException (i.e. because you don't check if cycledStack is null before calling a method with it)? Is your count not incrementing (i.e. because your condition is never true - ItemStack != Item)? Is the message not getting sent (I don't see any code to send a chat message...)?

[Daedalus]

Wow, forgot the error... Sorry...

 

Yes, it's a NullPointerException, and I feel more like an idiot because checking if it was null or not fixed that issue, and then it wasn't counting which I fixed by changing:

 

if (cycledStack.getItem().equals(heldStack))

 

To:

 

if (cycledStack.getItem().equals(heldStack.getItem()))

 

Thank you!

[coolAlias]

Np. Rookie mistakes (that every one of us has made)

 

Btw, since Items are all instantiated as singletons, you can compare using identity '==' rather than the #equals method (which does check identity, but also potentially a lot of other stuff e.g. for complex objects that are separate instances but may still considered equal).

// this is the typical way of comparing Items and Blocks (but NOT ItemStacks if you care about damage value and/or NBT data)
if (cycledStack.getItem() == heldStack.getItem())