How can i save the games inventory?

Questions & Answers
1

I have an inventory code, i am need to know how can I save it, when I load back the game
this is my inventory code

public delegate void OnItemChanged();
public OnItemChanged onItemChangeCallback;

public int space = 20;

public List<Item> items = new List<Item>();

public bool Add (Item item)
{
    if (!item.isDefaultItem)
    {
        if (items.Count >= space)
        {
            Debug.Log("Not enough room.");
            return false;
        }
        items.Add(item);
        
        if (onItemChangeCallback != null)
            onItemChangeCallback.Invoke();
    }

    return true;
}

public void Remove (Item item)
{
    items.Remove(item);

    if (onItemChangeCallback != null)
        onItemChangeCallback.Invoke();
}

my slot code

public Image icon;
public Button removeButton;

Item item;

public void AddItem(Item newItem)
{
    item = newItem;

    icon.sprite = item.icon;
    icon.enabled = true;
    removeButton.interactable = true;
}

public void ClearSlot()
{
    item = null;

    icon.sprite = null;
    icon.enabled = false;
    removeButton.interactable = false;
}

public void OnRemoveButton()
{
    Inventory.instance.Remove(item);
}

public void UseItem()
{
    if (item != null)
    {
        item.Use();
    }
}

and my inventory code

new public string name = "New Item";
public Sprite icon = null;
public bool isDefaultItem = false;

public virtual void Use()
{
    //Use the item
    //Something might happen
    Debug.Log("Using " + name);
}

public void RemoveFromInventory ()
{
    Inventory.instance.Remove(this);
}

please help!

2

In general, .saving and loading data in Unity is no different than in other C# applications. You’ll need:

  • A serializable class to hold the data you want to save – anything [System.Serializable]
  • A serializer/deserializer, such as .NET’s System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
  • A stream to (de)serialize – most likely a FileStream

I’ll provide a simple, but complete, example that demonstrates saving and loading a custom inventory class below. First, a preview:

159498-save-load-example.png

To test, you’ll need to add the Player component to a GameObject in your scene, then enter play mode. Pressing 1 adds to the inventory, 2 removes a random item, 3 prints the inventory to the console, 4 saves the current inventory, and 5 loads the saved inventory.

An inventory is just a list of items – this is what we’ll be serializing as our save data.

Assets/Inventory.cs

using System.Collections.Generic;
[System.Serializable]
public class Inventory
{
    public List<Item> items;
    public Inventory() { items = new List<Item>(); }
}

An item has a few simple properties. Note that it also has the Serializable attribute.

Assets/Item.cs

[System.Serializable]
public class Item
{
public string description;
public int value;

public Item(string description_, int value_)
{
    description = description_;
    value = value_;
}

public override string ToString() { return $"{description} -- {value}"; }

}

The player class holds the save/load logic, and some code to help test. The SaveInventory and LoadInventory functions are what’s most important.

Assets/Player.cs

using System.IO;
using UnityEngine;

public class Player : MonoBehaviour
{
    public Inventory inventory = new Inventory();
    string InventorySavePath => Application.persistentDataPath + "/inventory.save";

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.Alpha1)) { AddItemToInventory(); }
        if (Input.GetKeyDown(KeyCode.Alpha2))
        {
            if (inventory.items.Count > 0) { RemoveItemFromInventory(); }
        }
        if (Input.GetKeyDown(KeyCode.Alpha3)) { DebugInventory(); }
        if (Input.GetKeyDown(KeyCode.Alpha4)) { SaveInventory(); }
        if (Input.GetKeyDown(KeyCode.Alpha5)) { LoadInventory(); }
    }

    void DebugInventory()
    {
        foreach (var item in inventory.items)
        {
            Debug.Log(item);
        }
    }

    void AddItemToInventory()
    {
        var item = new Item(System.Guid.NewGuid().ToString(), Random.Range(1, 100));
        Debug.Log($"Adding item: {item}");
        inventory.items.Add(item);
    }

    void RemoveItemFromInventory()
    {
        var randomIdx = Random.Range(0, inventory.items.Count);
        var item = inventory.items[randomIdx];
        Debug.Log($"Removing item: {item}");
        inventory.items.RemoveAt(randomIdx);
    }

    void SaveInventory()
    {
        Debug.Log($"Saving inventory to file @ {InventorySavePath}");
        var stream = new FileStream(InventorySavePath, FileMode.Create, FileAccess.Write);
        var formatter = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
        formatter.Serialize(stream, inventory);
        stream.Close();
    }

    void LoadInventory()
    {
        Debug.Log($"Loading inventory from file @ {InventorySavePath}");
        if (File.Exists(InventorySavePath))
        {

            var stream = new FileStream(InventorySavePath, FileMode.Open, FileAccess.Read);
            var formatter = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
            inventory = (Inventory)formatter.Deserialize(stream);
            stream.Close();
        }
        else { Debug.LogError("Save file does not exist!"); }
    }
}

Hope this helps!