如何修复ArgumentException：JSON必须表示对象类型

Question

我正在统一获取网络api，但出现错误。这是错误。

ArgumentException：JSON必须表示一个对象类型。UnityEngine.JsonUtility.FromJson（System.String json，System.Type类型）（在C：/buildslave/unity/build/Modules/JSONSerialize/Public/JsonUtility.bindings.cs：42）UnityEngine.JsonUtility.FromJson [T]（System.String json）（在C：/buildslave/unity/build/Modules/JSONSerialize/Public/JsonUtility.bindings.cs：30）RestClient + d__3.MoveNext（）（位于Assets / _Scripts / RestClient.cs：34）UnityEngine.SetupCoroutine.InvokeMoveNext（System.Collections.IEnumerator枚举器，System.IntPtrreturnValueAddress）（在C：/buildslave/unity/build/Runtime/Export/Scripting/Coroutines.cs：17）

这是我的json响应

[
   {
      "id":"1",
      "name":"Yasir",
      "mobile":"0301",
      "password":"123"
   },
   {
      "id":"2",
      "name":"Mehmood",
      "mobile":"0302",
      "password":"123"
   },
   {
      "id":"3",
      "name":"Imran",
      "mobile":"0301",
      "password":"123"
   },
   {
      "id":"4",
      "name":"Iqbal",
      "mobile":"0302",
      "password":"123"
   }
]

ReastClient.cs

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

public class RestClient : MonoBehaviour
{
    private static RestClient _instance;
    public static RestClient Instance{
        get{
            if(_instance == null){
                _instance = FindObjectOfType<RestClient>();
                if(_instance == null){
                    GameObject go = new GameObject();
                    go.name =typeof(RestClient).Name;
                    _instance = go.AddComponent<RestClient>();
                }
            }
            return _instance;
        }
    }

    public IEnumerator Get(string url, System.Action<PlayerList> callBack)
    {
        using (UnityWebRequest www = UnityWebRequest.Get(url))
        {
            yield return www.SendWebRequest();
            if (www.isNetworkError)
            {
                print(www.error);
            }else if (www.isDone)
            {
                string jsonResult = System.Text.Encoding.UTF8.GetString(www.downloadHandler.data);
                PlayerList playerlist = JsonUtility.FromJson<PlayerList>(jsonResult);
                callBack(playerlist);
            }
        }
    }

}

Game.cs

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

public class Game : MonoBehaviour
{
    public string web_url = "";
    // Start is called before the first frame update
    void Start()
    {
        StartCoroutine(RestClient.Instance.Get(web_url,GetPlayers));
    }

    void GetPlayers(PlayerList playerlist)
    {
        foreach(Player player in PlayerList.players)
        {
            print("Player Id = " + player.id);

        }

    }
}

PlayerList.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
[System.Serializable]
public class PlayerList
{
    public static List<Player> players;
}

Player.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
[System.Serializable]
public class Player 
{
    public int id;
    public string name;
    public string mobile;
    public string password;
}

Answer 1

我猜想，JsonUtility.FromJson<T>期望一个对象不只是“数组”。所以json应该看起来像这样：

{
    "players": [
        {
            "id":"1",
            "name":"Yasir",
            "mobile":"0301",
            "password":"123"
        },
        ...
    ]
}

然后PlayerList的属性不能为静态。