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Unity - How to save and load lists (Binary Saving and Loading)

I'm trying to figure out how you would save & load list of data. I've gotten my code to work with single data but unsure of how a list one would work. I have a Character class so that means I can have multiple characters and I would like to save each of those character's hp, mana etc.
//SaveManager class that I can call from anywhere to save and load
public static class SaveManager
{
//SAVE
public static void Save(Character c)
{
BinaryFormatter formatter = new BinaryFormatter();
string path = Application.persistentDataPath + "/Save.save";
FileStream stream = new FileStream(path, FileMode.Create);
PartyData data = new PartyData(c);
formatter.Serialize(stream, data);
stream.Close();
}
//LOAD
public static PartyData Load()
{
string path = Application.persistentDataPath + "/Save.save";
if (File.Exists(path))
{
BinaryFormatter formatter = new BinaryFormatter();
FileStream stream = new FileStream(path, FileMode.Open);
PartyData data = formatter.Deserialize(stream) as PartyData;
stream.Close();
return data;
}
else
{
Debug.Log("Save FIle not Found");
return null;
}
}
}
PartyData class is what I'm using to save the Character data to.
[System.Serializable]
public class PartyData
{
public int hp;
public PartyData(Character cParty)
{
hp = cParty.HP;
}
}
Character class that contains stats etc
public class Character
{
public int HP { get; set; }
public int Mana { get; set; }
}
And then finally I have the CharacterParty class that I attach to a gameobject, this class contains multiple characters and calls the Save and Load functions:
public class CharacterParty : MonoBehaviour
{
[SerializeField] List<Character> characters;
public List<Character> Characters
{
get
{
return characters;
}
}
public void SaveParty()
{
SaveManager.SaveMC(characters[0]);
}
public void LoadParty()
{
PartyData data = SaveManager.LoadMC();
characters[0].HP = data.hp;
}
}
Now for testing purposes I tried saving & loading just the character's hp at index 0 and it works but now I wanna save a list of multiple character's hp and mana etc. I just don't know how the list would work with serialization saving and loading. My code probably needs a little bit of change to get the list working so I hope someone can help me out with an example.

Use JsonUtility class - this is Unity's built-in utility for JSON.
Also with this you can serialize any class without [System.Serializable]
Save:
// Parties list
List<PartyData> parties = new List<PartyData>();
// Add your parties here
// First argument is an instance of a class or any other object
// If second argument set to true, it makes JSON more human-readable
string json = JsonUtility.ToJson(parties, false);
// .. saving the file
Load:
// .. loading the file
// First argument is the JSON
List<PartyData> parties = JsonUtility.FromJson<List<PartyData>>(json);
// .. do stuff with the list
EDIT:
If you really want to use BinaryFormatter, then this is for saving:
List<PartyData> parties = new List<PartyData>();
// .. add parties
formatter.Serialize(stream, parties)
For loading:
List<PartyData> parties = formatter.Deserialize(stream) as List<PartyData>;
// .. do stuff
SECOND EDIT:
This one should work.
You would do something like that:
// Save class
[Serializable]
public class Save
{
public List<PartyData> parties;
// .. add other stuff here
}
// For loading
try
{
// Deserializing the save
Save save = (Save)formatter.Deserialize(stream);
// .. do stuff with other data if you added some
foreach (PartyData data in save.parties)
{
// .. do stuff with data
}
}
catch (Exception e)
{
// .. can you just acnowledge... E
// Oopsie! An error occured. The save file is probably COWWUPTED
Debug.LogWarning($"An error occured while loading the file: {e}");
}
// For saving
List<PartyData> parties = new List<PartyData>();
// .. add parties by calling parties.Add(party_here);
// Creating a save
Save save = new Save();
// Adding parties to save
save.parties = parties;
// Serialize to a file
formatter.Serialize(stream, parties);

how to Load json for windows build unity

I have tried alot of solution but no one is working in my case, my question is simple but i cant find any answer specially for windows build. I have tried to load json form persistent , streaming and resource all are working good in android but no any solution work for windows build. here is my code please help me.
public GameData gameData;
private void LoadGameData()
{
string path = "ItemsData";
TextAsset targetFile = Resources.Load<TextAsset>(path);
string json = targetFile.text;
gameData = ResourceHelper.DecodeObject<GameData>(json);
// gameData = JsonUtility.FromJson<GameData>(json);
print(gameData.Items.Count);
}
here is my data class
[Serializable]
public class GameData
{
[SerializeField]
public List<Item> Items;
public GameData()
{
Items = new List<Item>();
}
}
public class Item
{
public string Id;
public string[] TexturesArray;
public bool Active;
public Item()
{
}
public Item(string _id, string[] _textureArray , bool _active = true)
{
Id = _id;
TexturesArray = _textureArray;
Active = _active;
}
}

In order to be (de)serialized Item should be [Serializable]
using System;
...
[Serializable]
public class Item
{
...
}
Then you could simply use Unity's built-in JsonUtility.FromJson:
public GameData gameData;
private void LoadGameData()
{
string path = "ItemsData";
TextAsset targetFile = Resources.Load<TextAsset>(path);
string json = targetFile.text;
gameData = JsonUtility.FromJson<GameData>(json);
print(gameData.Items.Count);
}
For loading something from e.g. persistentDataPath I always use something like
var path = Path.Combine(Application.persistentDataPath, "FileName.txt")
using (var fs = File.Open(path, FileMode.Open, FileAccess.Read, FileShare.Read))
{
using (var sr = new StreamReader(fs))
{
var json = sr.ReadToEnd();
...
}
}
For development I actually place my file into StreamingAssets (streamingAssetsPath) while running the code in the Unity Editor.
Then on runtime I read from persistentFilePath. If the file is not there I first copy it from the streamingassetsPath the first time.
Here I wrote more about this approach

How to add new data and keep old existing data

I'm nearly done making my mobile game and I have have a DATA script using what is shown in this video. I have a list which holds the values of different challenges that the player can complete. How would I update the game so that I can add more challenges whilst still keeping the old data.
(The challenge data basically contains whether it has been completed and how far off being completed it is)
I have had a look at this guide but I don't quite understand it. I'm new to serialization.
Thank you in advance :)
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Xml;
using System.Xml.Serialization;
using System.IO;
[System.Serializable]
public class XMLManager : MonoBehaviour {
public static XMLManager dataManagement;
public gameData data;
void Awake()
{
//File.Delete(Application.dataPath + "/StreamingFiles/XML/item_data.xml");
System.Environment.SetEnvironmentVariable("MONO_REFLECTION_SERIALIZER", "yes");
dataManagement = this;
DontDestroyOnLoad(gameObject);
}
public void SaveData()
{
XmlSerializer serializer = new XmlSerializer(typeof(gameData));
System.Environment.SetEnvironmentVariable("MONO_REFLECTION_SERIALIZER", "yes");
FileStream stream = new FileStream(Application.dataPath + "/StreamingFiles/XML/item_data.xml", FileMode.Create);
serializer.Serialize(stream, data);
stream.Close();
}
public void LoadData()
{
System.Environment.SetEnvironmentVariable("MONO_REFLECTION_SERIALIZER", "yes");
if (File.Exists(Application.dataPath + "/StreamingFiles/XML/item_data.xml"))
{
XmlSerializer serializer = new XmlSerializer(typeof(gameData));
FileStream stream = new FileStream(Application.dataPath + "/StreamingFiles/XML/item_data.xml", FileMode.Open);
data = serializer.Deserialize(stream) as gameData;
stream.Close();
}
else
{
print("SaveData");
SaveData();
}
}
}
[System.Serializable]
public class gameData
{
public List<ChallengeStatus> Challenges;
public int HighScore;
public int CoinsCollected;
public List<bool> Unlocked;
public int GamesPlayed;
public int currentChallenge;
}
[System.Serializable]
public class ChallengeStatus
{
public int id;
public string title;
public int current;
public int max;
public int reward;
public bool completed;
public bool claimed;
}

First you should have a look at Unity XML Serialization and use proper attributes. You don't totally need them (except maybe the [XmlRoot]) but they let you customize your Xml file. If not provided Unity uses the variable names and uses sub-elements instead of attributes. However afaik this works only for primitives (int, float, string, bool, etc) and lists of them not for your own class ChallengeStatus. So at least for the list of your class you have to provide attributes:
[System.Serializable]
[XmlRoot("GameData")]
public class GameData
{
[XmlArray("Challenges")]
[XmlArrayItem("ChallengeStatus)]
public List<ChallengeStatus> Challenges;
//...
}
Now I don't really understand why you need to keep the old XML file when saving a new one but if you want to keep the current file I would add an int FileCounter .. ofcourse not in the same XML file ;) Might be e.g. via PlayerPrefs or a second simple text file only including the number or something similar.
Note it is better/saver to use Path.Combine for concatenate systempaths) - the overload taking an array of strings requires .Net4. Something like
private string FilePath
{
get
{
//TODO first load / read the FileCounter from somewhere
var paths = {
Application.dataPath,
"StreamingFiles",
"XML",
// here you get from somewhere and use that global FileCounter
string.Format("item_data_{0}.xml", FileCounter)};
return Path.Combine(paths);
}
}
Than you can increase that global FileCounter everytime you save the file.
public void SaveData()
{
//TODO somehow increase the global value
// store to PlayerPrefs or write a new file or ...
FileCounter += 1;
System.Environment.SetEnvironmentVariable("MONO_REFLECTION_SERIALIZER", "yes");
// better use the "using" keyword for streams
// use the FilePath field to get the filepath including the filecounter
using(FileStream stream = new FileStream(FilePath, FileMode.Create))
{
XmlSerializer serializer = new XmlSerializer(typeof(gameData))
serializer.Serialize(stream, data);
}
}
And read the file with the current FileCounter without increasing it
public void LoadData()
{
System.Environment.SetEnvironmentVariable("MONO_REFLECTION_SERIALIZER", "yes");
if (File.Exists(FilePath))
{
// better use a "using" block for streams
// use the FilePath field to get the filepath including the filecounter
using(FileStream stream = new FileStream(FilePath, FileMode.Open))
{
XmlSerializer serializer = new XmlSerializer(typeof(gameData));
data = serializer.Deserialize(stream) as gameData;
}
}
else
{
print("SaveData");
SaveData();
}
}
Hint 1:
As soon as you provide a constructor for your classes e.g.
public GameData(List<ChallengeStatus> challenges)
{
Challenges = challenges;
}
than you always have to also provide a default constructor (even if it does nothing)
public GameData(){ }
Hint 2:
You should always initialize your lists:
public class GameData
{
public List<ChallengeStatus> Challenges = new List≤ChallangeStatus>();
//...
public List<bool> Unlocked = new List<bool>();
//...
}
Hint 3:
Btw you don't need that [System.Serializable] for XmlManager since it inherits from MonoBehaviour which already is serializable anyway.

Adding new values to dictionary corrupts old save file

I am using a simple method of serializing and deserializing data for my save files which looks like this
//Object that is being stored
[System.Serializable]
public class GameData{
public int units;
public int scanRange;
public int gains;
public int reputation;
public int clicks;
public Dictionary<string,bool> upgradesPurchased;
public Dictionary<string,bool> upgradesOwned;
public Dictionary<string,bool> achievementsEarned;
public GameData(int units_Int,int scan_Range,int gains_Int,int reputation_Int,int clicks_Int,Dictionary<string,bool> upgrades_Purchased,Dictionary<string,bool> upgrades_Owned,Dictionary<string,bool> achievements_Earned){
units = units_Int;
scanRange = scan_Range;
gains = gains_Int;
reputation = reputation_Int;
clicks = clicks_Int;
upgradesPurchased = upgrades_Purchased;
upgradesOwned = upgrades_Owned;
achievementsEarned = achievements_Earned;
}
}
//Method that handles saving the object
public void SaveFile(){
string destination = Application.persistentDataPath + DATA_FILE;
FileStream file;
if (File.Exists (destination)) {
file = File.OpenWrite (destination);
} else {
file = File.Create (destination);
}
GameData data = new GameData (GameManager.Instance.units,GameManager.Instance.scanRange,GameManager.Instance.gains,GameManager.Instance.reputation,GameManager.Instance.clicks,UpgradeManager.Instance.upgradesPurchased,UpgradeManager.Instance.upgradesOwned,AchievementManager.Instance.achievementsEarned);
BinaryFormatter bf = new BinaryFormatter ();
bf.Serialize (file, data);
file.Close ();
NotificationsBar.Instance.ShowNotification ("Game saved success");
}
//Method that loads the object
public void LoadFile(){
string destination = Application.persistentDataPath + DATA_FILE;
FileStream file;
if (File.Exists (destination)) {
file = File.OpenRead (destination);
} else {
UpgradeManager.Instance.FirstLoad ();
return;
}
BinaryFormatter bf = new BinaryFormatter ();
GameData data = (GameData)bf.Deserialize (file);
file.Close ();
GameManager.Instance.units = data.units;
GameManager.Instance.scanRange = data.scanRange;
GameManager.Instance.gains = data.gains;
GameManager.Instance.reputation = data.reputation;
GameManager.Instance.clicks = data.clicks;
UpgradeManager.Instance.upgradesPurchased = data.upgradesPurchased;
UpgradeManager.Instance.upgradesOwned = data.upgradesOwned;
AchievementManager.Instance.achievementsEarned = data.achievementsEarned;
Debug.Log ("Units: " + data.units);
}
Theres a lot of code here but this is so everyone has a clear picture of what the entire system looks like
So the issue with this method is when adding a new value to the dictionary passed to GameData UpgradeManager.Instance.upgradesPurchased I will get an error when searching for data within the dictionary key not present in dictionary
My analysis is that due to the new value being added there is an offset in the dictionary from where the new value is placed and what used to be in that place
What I expected to happen when I first wrote out the code wa the dictionary would just autopopulate the new values and overwrite the old data
For a visual representation of what I mean lets say you have 2 upgrades
Upgrade1,Upgrade2
Now this is saved
Now the code changes and you have 3 upgrades
Upgrade1,Upgrade3,Upgrade2
What I assume would happen is the new value is just added into the save
So I am not exactly sure why this is happening....

Whilst I can't see the exact cause of the issue I would suggest the following:
First, take your save/load logic out of your GameData class and put it into a SaveDataManager class, that way you segregate responsibility.
From there, you can simplify your GameData class down to a struct making serialisation/desrialisation easier.
Then in your main game class whenever you have to load the game you can do something along the lines of:
SaveGameManger sgManager = new SaveGameManager(file);
gameData = sgManager.LoadGame()
This will make your code much easier to maintain and if this doesn't fix your problem it will be a lot easier to find.
Further to this, it will also allow you to build unit tests that verify the integrity of you load and save logic.
I've not had a chance to test it, but your separated and refactored code would look something like this (although it needs some validation checks added and whatnot):
using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
namespace temp
{
public class GameLoop
{
private SaveGameManager sgManager;
private GameData data;
private bool isPlaying;
public GameLoop()
{
sgManager = new SaveGameManager("MYSAVELOCATION");
data = sgManager.LoadGame();
isPlaying = true;
}
private void PlayGame()
{
while (isPlaying)
{
//All of your game code
}
}
}
public class SaveGameManager
{
private string saveFile;
private BinaryFormatter formatter;
public SaveGameManager(string file)
{
saveFile = file;
formatter = new BinaryFormatter();
}
public GameData LoadGame()
{
using (StreamReader reader = new StreamReader(saveFile))
{
return (GameData)formatter.Deserialize(reader.BaseStream);
}
}
public void SaveGame(GameData data)
{
using (StreamWriter writer = new StreamWriter(saveFile))
{
formatter.Serialize(writer.BaseStream, data);
}
}
}
[Serializable]
public struct GameData
{
public int units;
public int scanRange;
public int gains;
public int reputation;
public int clicks;
public Dictionary<string, bool> upgradesPurchased;
public Dictionary<string, bool> upgradesOwned;
public Dictionary<string, bool> achievementsEarned;
}
}
And I really would consider switching out your string keys for upgrades in favour of enums... Much less error prone.

Unexpected binary element 255 when serializing

I'm using Unity 2017 and wish to serialize save game data like so:
public void Save(Statistics data)
{
BinaryFormatter bf = new BinaryFormatter();
FileStream file = File.Create(Application.persistentDataPath
+ "/playerInfo.dat");
bf.Serialize(file, data);
file.Close();
}
The LevelData class is marked Serializable and contains only strings and ints. The class that implements IPersistentData meets those requirements too.
I did look for the problem and found that I should set an environment variable in my Awake method that I did, but that didn't solve anything. I'm using Windows 10 as operating system to develop on but the game will be made for Android.
When attempting to save, I always get this exception
SerializationException: Unexpected binary element: 255
System.Runtime.Serialization.Formatters.Binary.ObjectReader.ReadObject (BinaryElement element, System.IO.BinaryReader reader, System.Int64& objectId, System.Object& value, System.Runtime.Serialization.SerializationInfo& info)
Any sort of advice is welcome to get around the issue.
EDIT
Updating after trying the hints of Programmer:
The class I wish to serialize:
[Serializable]
public class Statistics
{
public int LastPlayedLevel;
public Statistics()
{
MusicVolume = 1f;
SFXVolume = 1f;
LevelDatas = new List<LevelData>();
LastPlayedLevel = 1;
}
public float MusicVolume;
public float SFXVolume;
public List<LevelData> LevelDatas;
}
And the LevelData:
[Serializable]
public class LevelData
{
public LevelData(int levelNumber,string name)
{
this.LevelNumber = levelNumber;
this.Name = name;
this.BestPercent = 0;
this.DeathCount = 0;
}
public int LevelNumber;
public string Name;
public int BestPercent;
public uint DeathCount;
}