How to save List to binary file

Question

I'm trying to create a little clicker game with unity and now I need to save Shop's items in a binary file. The below code is my Shop class which is called when I click on the button icon, I need to check if the shop data exists in my save file before loading the shop and if exists replace the default list with the saved one, example: The first time I click on the shop the game should save every shop item available with cost, name, image and level, when the player buy something the code saves the shop items/changes into the file and when the player opens the shop again it should reload the values from the save file.

I know how to save the info into a file if is just a boolean, int, float, etc but not a list

public class Shop : MonoBehaviour
{
    // Singleton Instance
    public static Shop Instance = null;
    [System.Serializable] public class ShopItem
    {
        public float costMultiplier;
        public string itemName;
        public Sprite image;
        public float price;
        public Button purchase;
        public int level;
    }

    [SerializeField] 
    public List<ShopItem> shopItemsList;

    GameObject ItemTemplate;
    GameObject ShopItemObj;
    [SerializeField] Transform ShopScrollView;
    public GameObject ShopCanvas;

    private void Awake()
    {
        SingletonSetup();
    }

    private void SingletonSetup()
    {
        if (Instance == null)
        {
            Instance = this;
        }
        else if (Instance != this)
        {
            Destroy(gameObject);
        }
    }

    private void Start()
    {
        ItemTemplate = ShopScrollView.GetChild(0).gameObject;

        int len = shopItemsList.Count;
        GameData data = SaveSystem.LoadData();
        for (int i = 0; i < len; i++)
        {
            ShopItemObj = Instantiate(ItemTemplate, ShopScrollView);
            /*if (data.firstRun)
            {*/
                ShopItemObj.transform.GetChild(0).GetComponent<Image>().sprite = shopItemsList[i].image;
                if (shopItemsList[i].level == 0)
                {
                    ShopItemObj.transform.GetChild(1).GetComponent<TextMeshProUGUI>().text = "$" + GameController.Instance.MoneyConverter(shopItemsList[i].price, GameController.Instance.scientificNumbers);
                }
                else
                {
                    ShopItemObj.transform.GetChild(1).GetComponent<TextMeshProUGUI>().text = "$" + GameController.Instance.MoneyConverter((shopItemsList[i].price * shopItemsList[i].costMultiplier), GameController.Instance.scientificNumbers);
                }
                ShopItemObj.transform.GetChild(2).GetComponent<TextMeshProUGUI>().text = shopItemsList[i].itemName;
                float price = shopItemsList[i].price;
                ShopItemObj.transform.GetChild(3).GetComponent<Button>().onClick.AddListener(() => { OnPuchase(price); });
                ShopItemObj.transform.GetChild(4).GetComponent<TextMeshProUGUI>().text = "level: " + shopItemsList[i].level;
            /*}
            else
            {
                ShopItemObj.transform.GetChild(0).GetComponent<Image>().sprite = data.shopItemsList[i].image;
                if (shopItemsList[i].level == 0)
                {
                    ShopItemObj.transform.GetChild(1).GetComponent<TextMeshProUGUI>().text = "$" + GameController.Instance.MoneyConverter(data.shopItemsList[i].price, GameController.Instance.scientificNumbers);
                }
                else
                {
                    ShopItemObj.transform.GetChild(1).GetComponent<TextMeshProUGUI>().text = "$" + GameController.Instance.MoneyConverter((data.shopItemsList[i].price * data.shopItemsList[i].costMultiplier), GameController.Instance.scientificNumbers);
                }
                ShopItemObj.transform.GetChild(2).GetComponent<TextMeshProUGUI>().text = data.shopItemsList[i].itemName;
                float price = data.shopItemsList[i].price;
                ShopItemObj.transform.GetChild(3).GetComponent<Button>().onClick.AddListener(() => { OnPuchase(price); });
                ShopItemObj.transform.GetChild(4).GetComponent<TextMeshProUGUI>().text = "level: " + data.shopItemsList[i].level;
            }*/
        }
        Destroy(ItemTemplate);
    }

    private void Update()
    {
        int len = shopItemsList.Count;
        for (int i = 0; i < len; i++)
        {
            if (!GameController.Instance.CanAffordPurchase(shopItemsList[i].price))
            {
                ShopItemObj.transform.GetChild(3).GetComponent<Button>().enabled = false;
            }
            else
            {
                ShopItemObj.transform.GetChild(3).GetComponent<Button>().enabled = true;
            }
        }
    }

    public void OnPuchase(float price)
    {
        if (GameController.Instance.CanAffordPurchase(price))
        {
            int len = shopItemsList.Count;
            for (int i = 0; i < len; i++)
            {
                if (shopItemsList[i].level < 1)
                {
                    ShopItemObj.transform.GetChild(1).GetComponent<TextMeshProUGUI>().text = "$" + GameController.Instance.MoneyConverter(shopItemsList[i].price, GameController.Instance.scientificNumbers);
                    GameController.Instance.PurchaseItem(price);
                }
                else
                {
                    ShopItemObj.transform.GetChild(1).GetComponent<TextMeshProUGUI>().text = "$" + GameController.Instance.MoneyConverter(shopItemsList[i].price * shopItemsList[i].costMultiplier, GameController.Instance.scientificNumbers);
                    shopItemsList[i].price = shopItemsList[i].price * shopItemsList[i].costMultiplier;
                    GameController.Instance.PurchaseItem(price * shopItemsList[i].costMultiplier);
                }
                ShopItemObj.transform.GetChild(4).GetComponent<TextMeshProUGUI>().text = "level: " + (shopItemsList[i].level += 1);
            }
            SaveSystem.SaveData();
        }
        else
        {
            Debug.LogError("Cannot affor the item");
        }
    }

    public void HideCanvas()
    {
        ShopCanvas.gameObject.SetActive(false);
    }

    public void ShowCanvas()
    {
        ShopCanvas.gameObject.SetActive(true);
    }
}

My GameData.cs:

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

[Serializable]
public class GameData
{    
    public static string saveFileName = "Clicker.unity2d";
    
    public float money;
    public bool firstRun;
    public bool scientificNumbers;
    public List<Shop.ShopItem> shopItemsList;


    public GameData()
    {
        money = GameController.Instance.money;
        firstRun = GameController.Instance.firstRun;
        scientificNumbers = GameController.Instance.scientificNumbers;
    }
}

public static class SaveSystem
{

    public static void SaveData()
    {
        BinaryFormatter formatter = new BinaryFormatter();

        string path = Application.persistentDataPath + "/" + GameData.saveFileName;
        FileStream stream = new FileStream(path, FileMode.Create);

        GameData data = new GameData();
        formatter.Serialize(stream, data);

        stream.Close();
    }

    public static GameData LoadData()
    {
        string path = Application.persistentDataPath + "/" + GameData.saveFileName;
        if (File.Exists(path))
        {
            BinaryFormatter formatter = new BinaryFormatter();

            FileStream stream = new FileStream(path, FileMode.Open);

            GameData data = formatter.Deserialize(stream) as GameData;

            stream.Close();

            return data;
        }
        else
        {
            return new GameData { firstRun = true };
        }
    }
}

you can use BinaryFormatter to binary serialize/deseralize objects. also, i suggest you to consider json serialization format to make your save files more portable. — denolk
– denolk, Commented Sep 10, 2020 at 14:14
This is all about your requirements. BinaryFormatter requires specific versions of assemblies loaded in the AppDomain. In the case of a platform upgrade or manifest mismatch, without custom AppDomain assemly loading, your existing save file may fail to deserialize. However, Json provides you a portable format that can be serialized/deserialized across platforms. It also useful if you will process or analyze a save file on your server side, may be a cheat prevention scenario. Further reading: serialization in .net — denolk
– denolk, Commented Sep 11, 2020 at 10:24
JSON is good but I have to somehow crypt it so it can't be an easy cheat? Instead of "money: 100" it should be something else. I've tried once base64 encrypt/decrypt but I don't know if it's good — Code9
– Code9, Commented Sep 11, 2020 at 22:07

Johny · Accepted Answer · 2020-09-10 14:26:39Z

1

Where should the list be saved? The list should be in an object (for example your GameData has also List<>), so you can use the function below to create a file and save your List using BinaryFormatter:

private void CreateGameFile(List<Shop.ShopItem> list)
        {
            string path = Path.Combine(Application.persistentDataPath + "/" + gameName + GetGameFileExtension());
            IFormatter formatter = new BinaryFormatter();
    
            /// Create game file.
            FileStream file = new FileStream(path, FileMode.CreateNew, FileAccess.ReadWrite);
    
            GameData game = new GameData
            {
                money = GameController.Instance.money,
                firstRun = GameController.Instance.firstRun,
                scientificNumbers = GameController.Instance.scientificNumbers,
                shopItemsList = list
            };
    
            formatter.Serialize(file, game);
            file.Close();
        }

answered Sep 10, 2020 at 14:26

Johny

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4 Comments

Code9 Over a year ago

Sorry, I forgot to mention I have a class to save/load the file. I can save and load data from the binary file already but I need to save and load my shopItemsList in my binary file

Johny Over a year ago

In your SaveData() function, you are just saving an empty GameData, therefore it won't load anything. Did you try the function I provided?

Code9 Over a year ago

I'm creating the file from LoadData but I can try it, for now I'm able to somehow save the list to a file and if running and calling data.whateverInTheList it works but not after running again the code, it throws a deserialization error (empty stream)

Johny Over a year ago

As I have already explained, you get the deserialization error because you are saving an empty GameData. GameData data = new GameData(); formatter.Serialize(stream, data); In this lines, you need to assign data in the GameData object you create before saving it like the function above.

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