JsonUtility returns {}

Questions & Answers
1

I have this JSON fetched from web service:

{"city":{"cityName":"*****","distance":0,"latitude":*****,"cityId":3,"longitude":*****}}

this works fine in web browsers but if I run my code in unity, unity just displays { }.

class Coordinate
{
    public string cityName;
    public string distance;
    public string latitude;
    public string cityId;
    public string longitude;
}

NameValueCollection values = new NameValueCollection();
    values.Add("latitude", latitude.ToString());
    values.Add("longitude", longitude.ToString());
    values.Add("radius_in_km", "0.5");

    Debug.Log("Latitude: " + values.Get("latitude") + ", Longitude: " + values.Get("longitude") + ", radius_in_km: " + values.Get("radius_in_km"));
    
    string url = "";

    WWW www = new WWW(url);
    Debug.Log("Requesting the following url: " + www.url);
    yield return www;

    Coordinate json = JsonUtility.FromJson<Coordinate>(www.text);

    if(www.error == null)
    {
        Debug.Log(json.cityId);
        Debug.Log("Loaded following JSON string " + JsonUtility.ToJson(www.text));
    }
    else
    {
        Debug.Log("ERROR: " + www.error);
    }

The code just gives me { }. Am I missing something? I am fairly new to JSON and Unity

2

I’m not familiar with Unity’s JSON functions and I’m not sure if these are the actual problems but I noticed two things:

  • Your class is called “Coordinate” but in the JSON the same thing is called “city”
  • Some values in the JSON seem to be integers or floats (the ones without quotes around the values) but in your class all values are strings.
3

As @UnrealSoftware says, your type definition doesn’t quite match your JSON - you’re trying to read a Coordinate, but your JSON actually describes a bigger object which contains a Coordinate as the “city” field.

So, you need to define a second class, like this:

[Serializable]
class CityInfo
{
   public Coordinate city;
}

and use FromJson with that. (Note that you should also put the [Serializable] attribute on your Coordinate class).