How to find if item is in inventory using these scripts?

Unity Engine
1

So I followed some YouTube videos to create an inventory system and I’m currently tweaking them to fit my needs. One need of mine is to find out if a key is in my inventory to be able to open a door. I already know the function I need to check if the trigger and key are pressed, but I also need to know if I have the key. Could someone help me? Thank you for your time.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using TMPro;
using CodeMonkey.Utils;

public class UI_Inventory : MonoBehaviour
{
    private Inventory inventory;
    private Transform itemSlotContainer;
    private Transform itemSlotTemplate;
    private PlayerUpDown player;

    public void Awake()
    {
        itemSlotContainer = transform.Find("itemSlotContainer");
        itemSlotTemplate = itemSlotContainer.Find("itemSlotTemplate");
    }

    public void SetPlayer(PlayerUpDown player)
    {
        this.player = player;
    }

    public void SetInventory(Inventory inventory)
    {
        this.inventory = inventory;

        inventory.OnItemListChanged += Inventory_OnItemListChanged;
        RefreshInventoryItems();
    }

    private void Inventory_OnItemListChanged(object sender, System.EventArgs e)
    {
        RefreshInventoryItems();
    }

    private void RefreshInventoryItems()
    {
        foreach (Transform child in itemSlotContainer)
        {
            if (child == itemSlotTemplate) continue;
            Destroy(child.gameObject);
        }

        int x = 0;
        int y = 0;
        float itemSlotCellSize = 100f;
        foreach (Item item in inventory.GetItemList())
        {
            RectTransform itemSlotRectTransform = Instantiate(itemSlotTemplate, itemSlotContainer).GetComponent<RectTransform>();
            itemSlotRectTransform.gameObject.SetActive(true);

            itemSlotRectTransform.GetComponent<Button_UI>().ClickFunc = () =>
            {

            };
            itemSlotRectTransform.GetComponent<Button_UI>().MouseRightClickFunc = () =>
            {
                // Drop item
                inventory.RemoveItem(item);
                ItemWorld.DropItem(player.GetPosition(), item);
            };

            itemSlotRectTransform.anchoredPosition = new Vector2(x * itemSlotCellSize, y * itemSlotCellSize + 100);
            Image image = itemSlotRectTransform.Find("image").GetComponent<Image>();
            image.sprite = item.GetSprite();

            x++;
            if (x > 4)
            {
                x = 0;
                y++;
            }
        }
    }
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System;

[Serializable]
public class Item
{
    public enum ItemType
    {
        Red,
        Blue,
        Key,
    }

    public ItemType itemType;
    public int amount;

    public Sprite GetSprite()
    {
        switch (itemType)
        {
            default:
            case ItemType.Red: return ItemAssets.Instance.redItem;
            case ItemType.Blue: return ItemAssets.Instance.blueItem;
            case ItemType.Key: return ItemAssets.Instance.keyItem;
        }
    }

    public bool IsStackable()
    {
        switch (itemType)
        {
            default:
            case ItemType.Red:
            case ItemType.Blue:
                return true;
            case ItemType Key:
                return false;
        }
    }
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System;

public class Inventory
{
    public event EventHandler OnItemListChanged;

    private List<Item> itemList;

    public Inventory()
    {
        itemList = new List<Item>();
    }

    public void AddItem(Item item)
    {
        if (item.IsStackable())
        {
            bool itemAlreadyInInventory = false;
            foreach (Item inventoryItem in itemList)
            {
                if (inventoryItem.itemType == item.itemType)
                {
                    inventoryItem.amount += item.amount;
                    itemAlreadyInInventory = true;
                }
            }
            if (!itemAlreadyInInventory)
            {
                itemList.Add(item);
            }
        }
        else
        {
            itemList.Add(item);
        }
        OnItemListChanged?.Invoke(this, EventArgs.Empty);
    }

    public List<Item> GetItemList()
    {
        return itemList;
    }

    public void RemoveItem(Item item)
    {
        if (item.IsStackable())
        {
            Item itemInInventory = null;
            foreach (Item inventoryItem in itemList)
            {
                if (inventoryItem.itemType == item.itemType)
                {
                    inventoryItem.amount -= item.amount;
                    itemInInventory = inventoryItem;
                }
            }
            if (itemInInventory != null && itemInInventory.amount <= 0)
            {
                itemList.Remove(itemInInventory);
            }
        }
        else
        {
            itemList.Remove(item);
        }
        OnItemListChanged?.Invoke(this, EventArgs.Empty);
    }
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;

public class PlayerUpDown : MonoBehaviour
{
    public float moveSpeed = 5f;

    public Rigidbody2D rb;
    public Animator animator;

    Vector2 movement;

    private Inventory inventory;

    [SerializeField] private UI_Inventory uiInventory;

    private void Update()
    {
        movement.x = Input.GetAxisRaw("Horizontal");
        movement.y = Input.GetAxisRaw("Vertical");

        animator.SetFloat("Horizontal", movement.x);
        animator.SetFloat("Vertical", movement.y);
        animator.SetFloat("Speed", movement.sqrMagnitude);
    }

    private void FixedUpdate()
    {
        rb.MovePosition(rb.position + movement * moveSpeed * Time.deltaTime);
    }

    private void Awake()
    {
        {
            inventory = new Inventory();
            uiInventory.SetInventory(inventory);

            uiInventory.SetPlayer(this);
        }
    }

    private void OnTriggerStay2D(Collider2D collider)
    {
        Debug.Log("This is called every frame.");
        ItemWorld itemWorld = collider.GetComponent<ItemWorld>();
        if (itemWorld != null && InputKeyPressed())
        {
            inventory.AddItem(itemWorld.GetItem());
            itemWorld.DestroySelf();
        }
        else if (collider.CompareTag("Door") && InputKeyPressed())
        {
            Debug.Log("Door is unlocked.");
            SceneManager.LoadScene(1);
        }
    }

    private bool InputKeyPressed()
    {
        return Input.GetKeyDown(KeyCode.E);
    }

    public Vector3 GetPosition()
    {
        return transform.position;
    }
}
2 
//In your OnCollision Door detect

foreach (Item item in inventory.GetItemList())
{
    if (item.itemType == ItemType.Key)
    {
        //Open door
        //Remove key
        //Add effect .. etc...
    }
}

If you have different keys then you have to modify the item class and add a more complex key structure
Maybe you want to open a blue door with a blue key (or something like that)

3

AND VWALLA IT WORKS. Thank you kind stranger.