Skelyvelocirap Posted July 17, 2021 Share Posted July 17, 2021 This is pretty self explanatory but i am trying to attach an inventory to one of my items. I know that i should be using capabilities for this but I'm not sure where i should put it for an item. Would it go inside of initCapabilities(), and if so how would i use that? I tried to take a look at how other mods do this but every mod seems to do it a different way and all of which require some kind of GUI(which I do not want). Of course there is the forge docs but their isn't enough documentations for doing so to items, it mostly explains for tile entities. Anything else i could find is too old to be any use with the complete API reworks basically every other version. Could someone help me with this? I was able to solve this issue last time i encountered it by simply adding the name of the stored item to the nbt but I'm afraid this wont work for this as I need to be able to have more than one slots. Quote Link to comment Share on other sites More sharing options...
kiou.23 Posted July 17, 2021 Share Posted July 17, 2021 You need a capability, and a capability provider. the capability is just a class which will hold your arbitrary data, for an Inventory, you want an IItemHandler (which handles ItemStacks). forge already has a default implementation of IItemHandler called ItemStackHandler, however you can create your own for custom behaviour. the capability provider is a class which implements ICapabilityProvider (orICapabilitySerializable<INBT> if you need save and load the data between sessions). In it's getCapability method, if the requested capability is your capability (or if it is just an inventory you can use CapabiltiyItemHandler.ITEM_HANDLER_CAPABILITY), and then return a lazy instance of it. Quote Link to comment Share on other sites More sharing options...
Skelyvelocirap Posted July 17, 2021 Author Share Posted July 17, 2021 Ohhhhhhh, thats how you get access to those methods. I knew you used to get those in 1.12.2 but completely forgot how, that answers that! So now i simply add an IInventory to the item along with implementing the capability right? Quote Link to comment Share on other sites More sharing options...
kiou.23 Posted July 18, 2021 Share Posted July 18, 2021 an IItemStackHandler, not an IInventory, they have a better api Quote Link to comment Share on other sites More sharing options...
Skelyvelocirap Posted July 18, 2021 Author Share Posted July 18, 2021 public class ParcelItem extends Item implements ICapabilityProvider { LazyOptional<ItemStackHandler> inventoryHandler = LazyOptional.of(this); public ParcelItem(Properties properties) { super(properties); } @Override public <T> LazyOptional<T> getCapability(Capability<T> cap, Direction side) { if(cap == CapabilityItemHandler.ITEM_HANDLER_CAPABILITY) { return inventoryHandler.cast(); } return null; } } Alright, i will make sure to use that instead, although, this is currently what I have. From the docs i understand i have to use a lazy optional and use the IItemHandler(im guessing replacing it with ItemStackHandler is fine consider it uses IItemHandler as a base). I thought i could pass the class as the supplier though but it seems i was mistaken. What exactly am i supposed to pass to it? Am i even supposed to do it like this? Quote Link to comment Share on other sites More sharing options...
poopoodice Posted July 18, 2021 Share Posted July 18, 2021 It's a supplier that supplies an instance, so of(() -> new MyProvider(); or just of(MyProvider::new) Quote Link to comment Share on other sites More sharing options...
Skelyvelocirap Posted July 18, 2021 Author Share Posted July 18, 2021 Hmmm, it still doesn't work. The type ParcelItem does not define ParcelItem() that is applicable here Im guessing this is due to the argument in the constructor but im not really sure how to fix that. Quote Link to comment Share on other sites More sharing options...
Draco18s Posted July 18, 2021 Share Posted July 18, 2021 (edited) Items can't be CapabilityProviders (unless you want all copies of your item to share that data). Item inventories belong to ItemStacks. Override initCapabilities. Edited July 18, 2021 by Draco18s Quote Apparently I'm a complete and utter jerk and come to this forum just like to make fun of people, be confrontational, and make your personal life miserable. If you think this is the case, JUST REPORT ME. Otherwise you're just going to get reported when you reply to my posts and point it out, because odds are, I was trying to be nice. Exception: If you do not understand Java, I WILL NOT HELP YOU and your thread will get locked. DO NOT PM ME WITH PROBLEMS. No help will be given. Link to comment Share on other sites More sharing options...
Skelyvelocirap Posted July 18, 2021 Author Share Posted July 18, 2021 Alright, how would i use that then? Quote Link to comment Share on other sites More sharing options...
poopoodice Posted July 18, 2021 Share Posted July 18, 2021 Return your capability provider there Quote Link to comment Share on other sites More sharing options...
Skelyvelocirap Posted July 18, 2021 Author Share Posted July 18, 2021 How do i check the type of capability its returning for with this method though? Quote Link to comment Share on other sites More sharing options...
kiou.23 Posted July 18, 2021 Share Posted July 18, 2021 11 hours ago, Skelyvelocirap said: How do i check the type of capability its returning for with this method though? you don't. You'll check the capability type in the provider; And in your initCapabilities you'll return an instance of said provider. If your item needs more than one capability, just make a Provider which provides multiple capabilties depending on which one is requested. Quote Link to comment Share on other sites More sharing options...
Skelyvelocirap Posted July 18, 2021 Author Share Posted July 18, 2021 26 minutes ago, kiou.23 said: you don't. You'll check the capability type in the provider; I am really confused tbh. How exactly am I supposed to do that? Quote Link to comment Share on other sites More sharing options...
kiou.23 Posted July 18, 2021 Share Posted July 18, 2021 35 minutes ago, Skelyvelocirap said: I am really confused tbh. How exactly am I supposed to do that? the job of the CapabilityProvider is too handle and expose all the capabilities for an object. In the getCapabilities method, it will check for which capability that is being requested, and provide it. in the Item class, the point of the initCapabilities method, is just to say which CapabilityProvider will handle it's data. so if what you need is an Inventory, you'd have an "InventoryProvider", which when the ITEM_STACK_HANDLER capability was requested, would return the Inventory. and in the item which has this inventory data, it would return this InventoryProvider in initCapabilities. Here's an example: public class BackpackCapabilityProvider implements ICapabilitySerializable<INBT> { // BackpackItemStackHandler is just an extension of ItemStackHandler which makes sure no Backpack can be put in the inventory private BackpackItemStackHandler backpackItemStackHandler; // This instantiates the Inventory only when it is first requested, and then caches it @Nonnull private BackpackItemStackHandler getCachedInventory() { if (backpackItemStackHandler == null) backpackItemStackHandler = new BackpackItemStackHandler(); return backpackItemStackHandler; } private final LazyOptional<IItemHandler> lazyInventory = LazyOptional.of(this::getCachedInventory); // Provides the Inventory @Nonnull @Override public <T> LazyOptional<T> getCapability(@Nonnull Capability<T> cap, Direction side) { if (cap == CapabilityItemHandler.ITEM_HANDLER_CAPABILITY) return (LazyOptional<T>)(lazyInventory); // If we needed to provide more than one capability, we'd simply add another check: // if (cap == SOME_OTHER_CAPABILITY) return (otherCapability) return LazyOptional.empty(); } // Saves the Inventory data to an NBT tag, so that it can be saved to disk @Override public INBT serializeNBT() { return CapabilityItemHandler.ITEM_HANDLER_CAPABILITY.writeNBT(getCachedInventory(), null); } // Reads the Inventory data from an NBT tag that was saved to disk @Override public void deserializeNBT(INBT nbt) { CapabilityItemHandler.ITEM_HANDLER_CAPABILITY.readNBT(getCachedInventory(), null, nbt); } } Quote Link to comment Share on other sites More sharing options...
Draco18s Posted July 18, 2021 Share Posted July 18, 2021 15 hours ago, Skelyvelocirap said: How do i check the type of capability its returning for with this method though? You don't. That's the point in time when you are saying "THIS ITEM HAS A CAPABILITY!" and it gets called once on itemstack creation. The getCapability method that you need to check against is different. Quote Apparently I'm a complete and utter jerk and come to this forum just like to make fun of people, be confrontational, and make your personal life miserable. If you think this is the case, JUST REPORT ME. Otherwise you're just going to get reported when you reply to my posts and point it out, because odds are, I was trying to be nice. Exception: If you do not understand Java, I WILL NOT HELP YOU and your thread will get locked. DO NOT PM ME WITH PROBLEMS. No help will be given. Link to comment Share on other sites More sharing options...
Skelyvelocirap Posted July 20, 2021 Author Share Posted July 20, 2021 On 7/18/2021 at 12:21 PM, kiou.23 said: the job of the CapabilityProvider is too handle and expose all the capabilities for an object. In the getCapabilities method, it will check for which capability that is being requested, and provide it. in the Item class, the point of the initCapabilities method, is just to say which CapabilityProvider will handle it's data. so if what you need is an Inventory, you'd have an "InventoryProvider", which when the ITEM_STACK_HANDLER capability was requested, would return the Inventory. and in the item which has this inventory data, it would return this InventoryProvider in initCapabilities. Here's an example: public class BackpackCapabilityProvider implements ICapabilitySerializable<INBT> { // BackpackItemStackHandler is just an extension of ItemStackHandler which makes sure no Backpack can be put in the inventory private BackpackItemStackHandler backpackItemStackHandler; // This instantiates the Inventory only when it is first requested, and then caches it @Nonnull private BackpackItemStackHandler getCachedInventory() { if (backpackItemStackHandler == null) backpackItemStackHandler = new BackpackItemStackHandler(); return backpackItemStackHandler; } private final LazyOptional<IItemHandler> lazyInventory = LazyOptional.of(this::getCachedInventory); // Provides the Inventory @Nonnull @Override public <T> LazyOptional<T> getCapability(@Nonnull Capability<T> cap, Direction side) { if (cap == CapabilityItemHandler.ITEM_HANDLER_CAPABILITY) return (LazyOptional<T>)(lazyInventory); // If we needed to provide more than one capability, we'd simply add another check: // if (cap == SOME_OTHER_CAPABILITY) return (otherCapability) return LazyOptional.empty(); } // Saves the Inventory data to an NBT tag, so that it can be saved to disk @Override public INBT serializeNBT() { return CapabilityItemHandler.ITEM_HANDLER_CAPABILITY.writeNBT(getCachedInventory(), null); } // Reads the Inventory data from an NBT tag that was saved to disk @Override public void deserializeNBT(INBT nbt) { CapabilityItemHandler.ITEM_HANDLER_CAPABILITY.readNBT(getCachedInventory(), null, nbt); } } Alright so, ive gotten it to work but now im a bit confused as to how i add items to the inventory. Im guessing its not as simple as inventoryHandler#setStackInSlot() is it? Would this add it to the item or itemstack? Quote Link to comment Share on other sites More sharing options...
Draco18s Posted July 20, 2021 Share Posted July 20, 2021 ItemStackHandler#insert and ItemStackHandler#Extract Quote Apparently I'm a complete and utter jerk and come to this forum just like to make fun of people, be confrontational, and make your personal life miserable. If you think this is the case, JUST REPORT ME. Otherwise you're just going to get reported when you reply to my posts and point it out, because odds are, I was trying to be nice. Exception: If you do not understand Java, I WILL NOT HELP YOU and your thread will get locked. DO NOT PM ME WITH PROBLEMS. No help will be given. Link to comment Share on other sites More sharing options...
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