Save GameObject information List in json file

Unity Engine
1

hi Guys, i have a problem and i don’t know where it is ,can you help me ? so i have wrote this script for save all gameObject in scene in file json the problem is that the list is null why ?
this is the script :

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

public class JsonManager : MonoBehaviour
{
string json;
GameObjectInScene gameObjectInScene;
public List gameObjectList;
[Header(“Check this for save level”)]
public bool save = false;

void Awake()
{
gameObjectList = new List();
}

void Start()
{

if (save)
{
SaveJson();

}

}

void SaveJson()
{

foreach (GameObject gObject in GameObject.FindObjectsOfType())
{

gameObjectInScene = new GameObjectInScene(gObject.name, gObject.transform.localScale, gObject.transform.position, gObject.transform.rotation);
gameObjectList.Add(gameObjectInScene);

}
json = JsonUtility.ToJson(gameObjectList);

}

}

public class GameObjectInScene : MonoBehaviour
{
public string name;
public Vector3 scale;
public Vector3 position;
public Quaternion rotation;

public GameObjectInScene(string name, Vector3 scale, Vector3 position, Quaternion rotation)
{
this.name = name;
this.scale = scale;
this.position = position;
this.rotation = rotation;
}
}

how is possible that the list is null pls help me

2

Wrap the list in a class. From the JsonUtility docs:

…passing an array to this method will not produce a JSON array containing each element, but an object containing the public fields of the array object itself (of which there are none) [i.e., null]. To serialize the actual content of an array or primitive type, it is necessary to wrap it in a class or struct.

(p.s. - In future posts, please use code tags. They make it easier for others to read your code.)

3 Likes
3

thank you man i have done,

Thank you man i have done in this way :
[Serializable]
public class GameObjectInScene
{
public string name;
public Vector3 scale;
public Vector3 position;
public Quaternion rotation;

public GameObjectInScene(string name, Vector3 scale, Vector3 position, Quaternion rotation)
{
this.name = name;
this.scale = scale;
this.position = position;
this.rotation = rotation;
}
}

serializable tag was the Key - i love you (how can i do for vote your answer like the best ?)

4

Happy to help!

(p.s. - Please remember code tags. ;))

5

I wanted to follow up on this. I’m trying to do something similar. Working on a more basic project to build the more complex one.
I have the following

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

public class JSONRecorder : MonoBehaviour {

    private string path;
    private string filename = "MyList.JSON";

    public int id;
    public string nameString;
    public double doubleNum;

    public MyClass myClass;
    public List<MyClass> myClassList;

    void Start () {
        myClassList = new List<MyClass>();
        path = Application.persistentDataPath + "/" +filename;
    }

    void RecordIdName(int i, string s) {
        myClass = new MyClass(i, s);
        myClassList.Add(myClass);
        string contents = JsonUtility.ToJson(myClassList);
        File.WriteAllText (path, contents);
    }
}

I have MyClass scripted out, too.

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

[System.Serializable]

public class MyClass{

    public int identity;
    public string theName;
    public double doubleNumber;

    public MyClass(int id, string name){
        identity = id;
        theName = name;
    }

    public MyClass(int id, string name, double num){
        identity = id;
        theName = name;
        doubleNumber = num;
    }
}

The JSON file is just blank brackets { }
When I debug myClass it shows “identity”:23,“theName”:BubbaGump,“doubleNumber”:0
Just as it should.
when I debug the myClassList it shows: System.Collections.Generic.List`1[MyClass]
Clearly something is going wrong in my list, but can’t figure it out, especially where it looks like the code is the same.

6

Unity serializer limited to serializing objects. You can serialize object containing list, but not the list alone. You want this

[Serializable]
class Container {
    public List<MyClass> Content = new List<MyClass>();
}
1 Like
7

Thanks, Palex-nx! That did it!