Create multiple structs from JSON file

Unity Engine
1

Hello, I am trying to figure out the best way to create a list of structs from one JSON file. The JSON file has data organized as such:

{
“FIELD1”: “ORIGIN”,
“FIELD2”: “874”,
“FIELD3”: “37.7848”,
“FIELD4”: “-122.7278”,
“FIELD5”: “San Francisco Bay, CA”,
“FIELD6”: “United States”
}
{
“FIELD1”: “ORIGIN”,
“FIELD2”: “36”,
“FIELD3”: “37.5242”,
“FIELD4”: “-77.4932”,
“FIELD5”: “Richmond, VA”,
“FIELD6”: “United States”
}
etc…

My code currently looks like this

public class ParseJSON : MonoBehaviour {

    public struct Attendee {
        public string FIELD1;
        public string FIELD2;
        public string FIELD3;
        public string FIELD4;
        public string FIELD5;
        public string FIELD6;
    }
 
    List<Attendee> attendees = new List<Attendee>();

    void Start(){
         ReadData();
    }

    void ReadData(){
        Attendee = new Attendee();
        //Trying to figure out how to read through my JSON data
        //and populate here
        attendees.add(attendee);
    }
}

I have looked in the Unity documentation and I have used the example to read JSON to a Struct when the JSON file only contains one entry, I am just trying to figure out how to handle multiple entries in one JSON file. Thanks in advanced for any help that you may be able to provide!

2

If that’s the exact JSON, it’s invalid, it needs a comma between objects, and the objects need to be in a list. So it would look like:

[
{
"FIELD1": "ORIGIN",
"FIELD2": "874",
"FIELD3": "37.7848",
"FIELD4": "-122.7278",
"FIELD5": "San Francisco Bay, CA",
"FIELD6": "United States"
},
{
"FIELD1": "ORIGIN",
"FIELD2": "36",
"FIELD3": "37.5242",
"FIELD4": "-77.4932",
"FIELD5": "Richmond, VA",
"FIELD6": "United States"
}
]

JsonUtility doesn’t support having a list as the top level object, but that’s fairly easy to work around. See How to load an array with JsonUtility? - Unity Engine - Unity Discussions

But essentially you wouldn’t read one object at a time, you’d read the entire file in one call and a List (or a class containing such a list) would be the result.

3 
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.IO;

public class ParseJSON : MonoBehaviour {

    string jsonString;
    public TextAsset jsonTextAsset;

    [System.Serializable]
    public struct Attendee {
        public string FIELD1;
        public string FIELD2;
        public string FIELD3;
        public string FIELD4;
        public string FIELD5;
        public string FIELD6;
        public string FIELD7;
        public string FIELD8;
        public string FIELD9;
        public string FIELD10;
        public string FIELD11;
        public string FIELD12;
        public string FIELD13;
        public string FIELD14;
        public string FIELD15;
    }

    [System.Serializable]
    public class AttendeeList {
        public Attendee[] attendees;
    }

    void Start () {
        ReadData ();
    }
      
    private void ReadData(){
        jsonString = jsonTextAsset.text;
        var a = JsonUtility.FromJson<AttendeeList> (jsonString);
    }
}

Thanks for the help, my code currently looks like this, but it is throwing a "ArgumentException: JSON must represent an object type. Any idea why?

Also, my JSON file looks exactly like the one you posted (Except with 15 fields), I had just quickly written an example before of the type of fields that I have. Thanks again!

4

After doing some more digging around, I found a solution that allows me to easily convert from Json to an array of structs. Thanks again for your help.

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

public class ParseJSON : MonoBehaviour {

    string jsonString;
    public TextAsset jsonTextAsset;

    [System.Serializable]
    public struct Attendee {
        public string FIELD1;
        public string FIELD2;
        public string FIELD3;
        public string FIELD4;
        public string FIELD5;
        public string FIELD6;
        public string FIELD7;
        public string FIELD8;
        public string FIELD9;
        public string FIELD10;
        public string FIELD11;
        public string FIELD12;
        public string FIELD13;
        public string FIELD14;
        public string FIELD15;
    }

    void Start () {
        ReadData ();
    }
       
    private void ReadData(){
        jsonString = jsonTextAsset.text;
        Attendee[] attendees = JsonHelper.getJsonArray<Attendee> (jsonString);
        foreach (Attendee a in attendees) {
            Debug.Log (a.FIELD1);
        }
    }
}

public class JsonHelper {
    public static T[] getJsonArray<T>(string json)
    {
        string newJson = "{ \"array\": " + json + "}";
        Wrapper<T> wrapper = JsonUtility.FromJson<Wrapper<T>> (newJson);
        return wrapper.array;
    }

    [System.Serializable]
    private class Wrapper<T>
    {
        public T[] array;
    }
}
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