So, I am using the ItemPickupEvent to check for items, and add a weight amount to the player that is parsed from my json. This all works fine except for this:

ItemStack item = event.pickedUp.getEntityItem();
int multiplier = item.stackSize;

 

It seems as though "multiplier" always returns 0. I could of sworn in 1.7.10, I never had this issue. Is there a new way of getting the stackSize with this event?

ItemPickupEvent

is fired after the

ItemStack

is added to the player's inventory with

InventoryPlayer#addItemStackToInventory

, which sets the

ItemStack

's stack size to 0.

 

You'll probably want to subscribe to

EntityItemPickupEvent

instead, since it's fired before the

ItemStack

is modified.

So those two events are slightly like RenderGameOverlayEvent.pre/post, correct?

Hm, alright. I'm using that now and it works quite well. Now, my other question is: is InventoryPlayer#inventoryChanged become true when anything enters or leaves the inventory? Or is it only in some cases?

Yes, it is always true as long as you have something in your inventory. Now, this was a problem, considering when the final item was removed, it wouldn't update. All I had to do was move how I set my weight into the checker for the inventoryChanged boolean, and only run the code if my newWeight (weight to be set), is not equal to my current weight. Here is how I do it in case someone is curious:

//Put in a LivingUpdateEvent. Simply set the player and my props for ease of access.

/* Start update inventory */
		InventoryPlayer inv = player.inventory;

		if(inv.inventoryChanged) {
			float currentWeight = props.getCurrentWeight();
			float newWeight = 0;

			for(int i = 0; i < inv.getSizeInventory(); i++) {
				ItemStack item = inv.getStackInSlot(i);
				int multiplier = 1;

				if(item != null) {
					multiplier = item.stackSize;

					try {
						float weight = WeightLimitJson.getItemWeight(item.getItem()) * multiplier;

						newWeight += weight;
					}catch (IOException e) {
						e.printStackTrace();
					}
				}
			}

			if(!player.worldObj.isRemote && newWeight != currentWeight)
				props.setWeight(newWeight);
		}