Basic Item Usage
Items are represented through an ItemStack. An ItemStack
is an inventory item with information such as
the amount of the item in the stack, the type of the item, and extra data such as durability. An Item itself
is the graphical representation of an ItemStack
as an entity. Be aware that you’ll always get a copy and not the
actual ItemStack
and thus, you will need to set it back into an inventory if desired.
Checking an Item’s Type
Checking the type of the item is very simple. You just need to call the ItemStack#getType() method.
import org.spongepowered.api.item.ItemType;
import org.spongepowered.api.item.ItemTypes;
import org.spongepowered.api.item.inventory.ItemStack;
public boolean isStick(ItemStack stack) {
ItemType type = stack.getType();
return type.equals(ItemTypes.STICK);
}
See how simple that is? Because sticks can stack, we can also find out how many are present.
Getting the number of items in an ItemStack
is relatively easy. The ItemStack#getQuantity() method will
handle this for us.
Modifying ItemStack Data
Manipulating data such as durability or the lore of an item is accomplished by simply using keys. You just need to specify the key that needs to be changed:
import org.spongepowered.api.data.key.Keys;
public void setUnbreakable(ItemStack stack) {
stack.offer(Keys.UNBREAKABLE, true);
}
In this, we specified that the Keys#UNBREAKABLE key is the key that we would like to change. We then set its
value to true
to imply that the item will never break. All of this is enclosed within the offer()
method of the
ItemStack
to return our changes back to the ItemStack
.
Different keys will require different values based on their job. For example, to change the lore of an item, one would
need to specify a List
of Text rather than an boolean or other value. It is also important to perform
checks to see if the key can actually apply to the item. For example, some items might not have durability or may
already have lore applied to the item.
import org.spongepowered.api.text.Text;
import java.util.List;
public void setLore(ItemStack stack, List<Text> itemLore) {
if (stack.get(Keys.ITEM_LORE).isPresent()) {
stack.offer(Keys.ITEM_LORE, itemLore);
}
}
Nota
Almost all API methods that return an ItemStack
only return a copy of it, so modifying it does not have any
impact on the real stack (e.g. in an inventory). You have to explicitly set it for your changes to persist.
Item Properties
Certain items may hold specific properties. For example, certain items can mine specific blocks, such as a diamond pickaxe to obsidian. Properties are used for determining if an item can cause an action without actually checking up the type of the item. We can check if an item can mine obsidian by using the HarvestingProperty of that item.
import org.spongepowered.api.block.BlockTypes;
import org.spongepowered.api.data.property.item.HarvestingProperty;
import java.util.Optional;
public boolean canMineObsidian(ItemStack stack) {
Optional<HarvestingProperty> optional =
stack.getProperty(HarvestingProperty.class);
if (optional.isPresent()) {
HarvestingProperty property = optional.get();
return property.getValue().contains(BlockTypes.OBSIDIAN);
}
return false;
}
This code will check to see if the item has a HarvestingProperty
, such as a pickaxe. If present, it will then
return if this item can harvest obsidian without the need to check the type of the item. This is useful in the event
that a mod or a Minecraft update adds a new tool with the capabilities of mining obsidian.
Comparing ItemStacks
The ItemStack
class contains a neat method for comparing two ItemStack
s. By using the
ItemStack#equalTo(ItemStack) method off of an already existing ItemStack
, we can see if the two
ItemStack
s are “equal”. That is, they share the same stack size, ItemType, and data. An example is
show below:
public boolean isEqual(ItemStack stack1, ItemStack stack2) {
return stack1.equalTo(stack2);
}