Deserializing JSON with JSONUltility: Lists?

Unity Engine
1

How exactly can I get a the latitude and longitude values from this JSON?

{"iss_position": {"longitude": "99.3445", "latitude": "-50.7022"}, "message": "success", "timestamp": 1571583963}

I’ve attached the code I am using to fetch and parse the JSON. It can display the message and timestamp values from the JSON just fine, but when doing that I do get this error (despite it working):

Unexpected node type.
UnityEngine.JsonUtility:FromJson(String)
<OnResponse>c__Iterator0:MoveNext() (at Assets/API.cs:17)
UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)

Any method I have tried of displaying a string in the iss_position list has failed. In addition, when I use Count to display the length of the list, it returns zero, so I assume I’m doing something very wrong. If anyone could point me in the right direction, I’d really appreciate it. Thanks!

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

public class API : MonoBehaviour {
    private const string url = "http://api.open-notify.org/iss-now.json";
    // Use this for initialization
    void Start () {
        WWW request = new WWW (url);
        StartCoroutine (OnResponse (request));
    }

    private IEnumerator OnResponse(WWW req) {
        yield return req;
        ISSData data = JsonUtility.FromJson<ISSData>(req.text);
        Debug.Log (data.message);
    }
}

[System.Serializable]
public class ISSData
{
    public string message;
    public int timestamp;
    public List<Position> iss_position;
}

[System.Serializable]
public class Position
{
    public string latitude;
    public string longitude;
}
2

The long and lat aren’t a list, they are two floats which you would place in a class. This should do it for you;

using System;
using System.Collections;
using UnityEngine;
using UnityEngine.Networking;

public class IssData : MonoBehaviour
{
    public IssInfo Info;

    private IEnumerator Start()
    {
        var www = new UnityWebRequest("http://api.open-notify.org/iss-now.json")
        {
            downloadHandler = new DownloadHandlerBuffer()
        };

        yield return www.SendWebRequest();

        if (www.isNetworkError || www.isHttpError)
        {
            Debug.Log("Error Loading ISS Data");
            yield break;
        }

       Info = JsonUtility.FromJson<IssInfo>(www.downloadHandler.text);
    }
}

[Serializable]
public class IssInfo
{
    public IssPosition iss_position;
    public string message;
    public int timestamp;
}

[Serializable]
public class IssPosition
{
    public float longitude;
    public float latitude;
}
3

Thanks so much! Everything works as intended now and I understand what I was doing wrong. I really appreciate your help!

4

Still that error shouldn’t happen. The field should just be ignored if the field type doesn’t match like “FromJson” does for other situations.
Please vote this issue here:

This error can happen if for example you get a malformed json and you want to handle the exception gracefully in your code by catching it. But this error is not catch-able.