Unity JSON 序列化程序不允许调用 JSON 字段 n JSON 个对象

Question

我无法从抓取的网站调用嵌套的 JSON 对象。抓取过程完美无缺，但 JSON 序列化部分是唯一的问题。我的代码如下所示：

private void GetHtmlAsync()
    {
        var url = "https://opentdb.com/api.php?amount=10";

        var httpClient = new HttpClient();
        var html = httpClient.GetStringAsync(url);

        DataContractJsonSerializer jsonSerializer = new DataContractJsonSerializer(typeof(MyDetail));
        MemoryStream stream = new MemoryStream(Encoding.UTF8.GetBytes(html.Result));
        stream.Position = 0;
        MyDetail dataContractDetail = (MyDetail) jsonSerializer.ReadObject(stream);
        text.text = "" + dataContractDetail.results[1];
        //text.text = string.Concat("Test: ", dataContractDetail.question, " " + dataContractDetail.correct_answer);
    }

    public class MyDetail
    {
        [DataMember]
        public Dictionary<string, questions> results
        {
            get;
            set;
        }

        public class questions
        {
            public string question { get; set; }
            public string correct_answer { get; set; }

        }

        [DataMember]
        public string response_code
        {
            get;
            set;
        }
    }

此代码无效，因为我尝试通过 "results[1]" 调用结果中的第一个对象，这 returns 在我附加 [=] 之后出现错误20=] 通过做 "results[1].question"。这种语法似乎很合理，所以我不明白为什么它不起作用。我的 JSON 文件如下所示：

{
"response_code": 0,
"results": [
{
"category": "Entertainment: Video Games",
"type": "multiple",
"difficulty": "medium",
"question": "What is the name of the virus in &quot;Metal Gear Solid 1&quot;?",
"correct_answer": "FOXDIE",
"incorrect_answers": [
"FOXENGINE",
"FOXALIVE",
"FOXKILL"
]
},
{
"category": "Geography",
"type": "multiple",
"difficulty": "easy",
"question": "What is the official language of Costa Rica?",
"correct_answer": "Spanish",
"incorrect_answers": [
"English",
"Portuguese",
"Creole"
]
},
{
"category": "Entertainment: Video Games",
"type": "multiple",
"difficulty": "medium",
"question": "In Fallout 4, which type of power armor is first encountered in the early mission &quot;When Freedom Calls&quot; in a crashed Vertibird?",
"correct_answer": "T-45",
"incorrect_answers": [
"T-51",
"T-60",
"X-01"
]
},
{
"category": "Politics",
"type": "boolean",
"difficulty": "medium",
"question": "George W. Bush lost the popular vote in the 2004 United States presidential election.",
"correct_answer": "False",
"incorrect_answers": [
"True"
]
},
{
"category": "Entertainment: Video Games",
"type": "multiple",
"difficulty": "medium",
"question": "In &quot;Halo 2&quot;, what is the name of the monitor of Installation 05?",
"correct_answer": "2401 Penitent Tangent",
"incorrect_answers": [
"343 Guilty Spark",
"031 Exuberant Witness",
"252 Biodis Expolsion"
]
},
{
"category": "Entertainment: Books",
"type": "multiple",
"difficulty": "medium",
"question": "The book &quot;Fahrenheit 451&quot; was written by whom?",
"correct_answer": "Ray Bradbury",
"incorrect_answers": [
"R. L. Stine",
"Wolfgang Amadeus Mozart",
"Stephen King"
]
},
{
"category": "Entertainment: Cartoon & Animations",
"type": "multiple",
"difficulty": "hard",
"question": "In &quot;Rick and Morty&quot;, from which dimension do Rick and Morty originate from?",
"correct_answer": "C-137",
"incorrect_answers": [
"J1977",
"C-136",
"C500-a"
]
},
{
"category": "Entertainment: Video Games",
"type": "multiple",
"difficulty": "hard",
"question": "In which game did the character &quot;Mario&quot; make his first appearance?",
"correct_answer": "Donkey Kong",
"incorrect_answers": [
"Super Mario Bros.",
"Super Mario Land",
"Mario Bros."
]
},
{
"category": "Entertainment: Film",
"type": "multiple",
"difficulty": "hard",
"question": "What was Humphrey Bogart&#039;s middle name?",
"correct_answer": "DeForest",
"incorrect_answers": [
"DeWinter",
"Steven",
"Bryce"
]
},
{
"category": "Entertainment: Cartoon & Animations",
"type": "boolean",
"difficulty": "medium",
"question": "In &quot;Avatar: The Last Airbender&quot; and &quot;The Legend of Korra&quot;, Lavabending is a specialized bending technique of Firebending.",
"correct_answer": "False",
"incorrect_answers": [
"True"
]
}
]
}

Answer 1

您的代码中存在很多问题。我不知道您正在使用的所有库，但我会这样做。

首先你开始 GetStringAsync 但你立即继续而不等待结果。我不知道您正在使用的所有库，当然也许它应该是这样的？

不过我宁愿使用Unity的UnityWebRequest.Get

private void GetHtmlAsync()
{
    StartCoroutine(DownloadJson());
}


private IEnumerator DownloadJson()
{
    var url = "https://opentdb.com/api.php?amount=10";
    using(var uwr = UnityWebRequest.Get(url))
    {
        // send the request and wait for result
        yield return uwr.SendWebRequest();
        // Check for success!
        if(uwr.isNetworkError || uwr.isHttpError || !string.IsNullOrWhiteSpace(uwr.error))
        {
            Debug.LogError($"Download failed with {uwr.responseCode} reason: {uwr.error}", this);
            yield break;
        }

        var json = uwr.DownloadHandler.text;

        // ... se below
    }
}

同样，我不知道您的 JSON 库，但您的 class 似乎与 JSON 数据结构不匹配（通过简单地将其插入 json2csharp)

[Serializable]
public class Result
{
    public string category;
    public string type;
    public string difficulty;
    public string question;
    public string correct_answer;
    public List<string> incorrect_answers;
}

[Serializable]
public class MyDetail
{
    public int response_code;
    public List<Result> results;
}

对于 Unity，我会使用 [Serializable] 并删除所有 {get;set} 以便不使用属性而是使用字段。

那么你可以简单地使用 Unity 的 JsonUtility

...
MyDetail dataContractDetail = JsonUtility.FromJson<MyDetail>(json);

然后如评论中所述，注意 c# 中的数组索引基于 0，因此 first 元素将是

var firstResult = dataContractDetail.results[0];

现在的问题是您希望在文本中看到什么？ firstResult 不是 string 而是具有不同成员的 class！你可以例如想显示像

这样的问题

text.text = firstResult.question;

Unity JSON 序列化程序不允许调用 JSON 字段 n JSON 个对象

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