Container

InventoryGun.java

package com.lionzxy.mysticalislands.gun;

import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.inventory.IInventory;
import net.minecraft.item.ItemStack;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.nbt.NBTTagList;
import net.minecraftforge.common.util.Constants;

/**
 * Created by lionzxy on 16.07.15.
 */
public class InventoryGun implements IInventory {
    public static final int INV_SIZE=3;
    public ItemStack[] itemStack=new ItemStack[INV_SIZE];
    private final ItemStack invItem;

    public InventoryGun(ItemStack stack) {
        this.invItem = stack;
        // Just in case the itemstack doesn't yet have an NBT Tag Compound:
        if (!stack.hasTagCompound()) {
            stack.setTagCompound(new NBTTagCompound());
        }
        // note that it's okay to use stack instead of invItem right there
        // both reference the same memory location, so whatever you change using
        // either reference will change in the other

        // Read the inventory contents from NBT
        readFromNBT(stack.getTagCompound());
    }

    public ItemStack getInvItem() {

        return invItem;
    }

    @Override
    public int getSizeInventory() {
        return itemStack.length;
    }

    @Override
    public ItemStack getStackInSlot(int slot) {
        return itemStack[slot];
    }

    @Override
    public ItemStack decrStackSize(int slot, int amount) {
        ItemStack stack = getStackInSlot(slot);
        if (stack != null) {
            if (stack.stackSize > amount) {
                stack = stack.splitStack(amount);
                markDirty();
            } else {
                setInventorySlotContents(slot, null);
            }
        }
        return stack;
    }

    @Override
    public ItemStack getStackInSlotOnClosing(int slot) {
        ItemStack stack = getStackInSlot(slot);
        if (stack != null) {
            setInventorySlotContents(slot, null);
        }
        return stack;
    }

    @Override
    public void setInventorySlotContents(int slot, ItemStack itemStack) {
        this.itemStack[slot] = itemStack;

        if (itemStack != null && itemStack.stackSize > this.getInventoryStackLimit()) {
            itemStack.stackSize = this.getInventoryStackLimit();
        }
        markDirty();
    }

    @Override
    public String getInventoryName() {
        return "Gun Inventory";
    }

    @Override
    public boolean hasCustomInventoryName() {
        return false;
    }

    @Override
    public int getInventoryStackLimit() {
        return 64;
    }

    @Override
    public void markDirty() {
        for (int i = 0; i < getSizeInventory(); ++i) {
            if (getStackInSlot(i) != null && getStackInSlot(i).stackSize == 0)
                itemStack = null;
        }
        writeToNBT(invItem.getTagCompound());
    }

    @Override
    public boolean isUseableByPlayer(EntityPlayer player) {
        return player.getHeldItem() == invItem;
    }

    @Override
    public void openInventory() {

    }

    @Override
    public void closeInventory() {

    }

    @Override
    public boolean isItemValidForSlot(int slot, ItemStack itemstack) {
        return false;
    }
    /**
     * A custom method to read our inventory from an ItemStack's NBT compound
     */
    public void readFromNBT(NBTTagCompound tagcompound) {
        // Gets the custom taglist we wrote to this compound.
        NBTTagList items = tagcompound.getTagList("ItemInventory", Constants.NBT.TAG_COMPOUND);

        for (int i = 0; i < items.tagCount(); ++i) {
            NBTTagCompound item = (NBTTagCompound) items.getCompoundTagAt(i);
            byte slot = item.getByte("Slot");

            // Just double-checking that the saved slot index is within our inventory array bounds
            if (slot >= 0 && slot < getSizeInventory()) {
                itemStack[i] = ItemStack.loadItemStackFromNBT(item);
            }
        }
    }

    /**
     * A custom method to write our inventory to an ItemStack's NBT compound
     */
    public void writeToNBT(NBTTagCompound tagcompound) {
        // Create a new NBT Tag List to store itemstacks as NBT Tags
        NBTTagList items = new NBTTagList();

        for (int i = 0; i < getSizeInventory(); ++i) {
            // Only write stacks that contain items
            if (getStackInSlot(i) != null) {
                // Make a new NBT Tag Compound to write the itemstack and slot index to
                NBTTagCompound item = new NBTTagCompound();
                item.setInteger("Slot", i);
                // Writes the itemstack in slot(i) to the Tag Compound we just made
                getStackInSlot(i).writeToNBT(item);

                // add the tag compound to our tag list
                items.appendTag(item);
            }
        }
        // Add the TagList to the ItemStack's Tag Compound with the name "ItemInventory"
        tagcompound.setTag("ItemInventory", items);
    }
}