Kotlin：Gson.fromJson()返回空值

w8f9ii69 于 2022-11-06 发布在 Kotlin

关注(0)|答案(1)|浏览(267)

我想使用Gson库解析Json文件。
由于某种原因，gson.fromJson（）方法返回null。
我已经在Android Studio中使用JSON到Kotlin插件创建了数据类，并使用Okhttp 4.9.0检索数据。

方法：

val request = Request.Builder().url(url).build()
        val client = OkHttpClient()
        client.newCall(request).enqueue(object: Callback {
            override fun onFailure(call: Call, e: IOException) {
                println("Failed your request")
            }

            override fun onResponse(call: Call, response: Response) {
                val body = response.body?.string()
                println(body)

                val gson = GsonBuilder().create()
                val result = gson.fromJson(body, YoutubeAPIModel::class.java)
            }
        })

YouTube API模型类：

class YoutubeAPIModel (val results: List<ApiModel>) {
}

ApiModel类别

data class ApiModel(
    val kind: String,
    val etag: String,
    val nextPageToken: String,
    val regionCode: String,
    val pageInfo: PageInfo,
    val items: List<Item>
)

项目类别

data class Item(
    val etag: String,
    val id: Id,
    val kind: String,
    val snippet: Snippet
)

代码段类

data class Snippet(
    val channelId: String,
    val channelTitle: String,
    val description: String,
    val liveBroadcastContent: String,
    val publishTime: String,
    val publishedAt: String,
    val thumbnails: Thumbnails,
    val title: String
)

缩略图类

data class Thumbnails(
    val default: Default,
    val high: High,
    val medium: Medium
)

默认类

data class Default(
    val height: Int,
    val url: String,
    val width: Int
)

中级

data class Medium(
    val height: Int,
    val url: String,
    val width: Int
)

高级

data class High(
    val height: Int,
    val url: String,
    val width: Int
)

正文：

{
  "kind": "youtube#searchListResponse",
  "etag": "753UP2XJw3TXoRmm3zEGF55fGP0",
  "nextPageToken": "CAUQAA",
  "regionCode": "CA",
  "pageInfo": {
    "totalResults": 1000000,
    "resultsPerPage": 5
  },
  "items": [
    {
      "kind": "youtube#searchResult",
      "etag": "WppfAkVnlxM77-c4C5YkSMZy8tE",
      "id": {
        "kind": "youtube#video",
        "videoId": "apsAw6pzK8k"
      },
      "snippet": {
        "publishedAt": "2020-11-27T15:15:00Z",
        "channelId": "UClkZ3VjIiEcW0iiQsI2VCzQ",
        "title": "Justin reagiert auf Montes kranken Gamingroom.. | Reaktion",
        "description": "PESO™: https://pesoclo.com/ (werbung) Twitch: http://twitch.tv/jstinLIVE PRO: http://youtube.com/jstin17 Instagram: http://instagram.com/jstin ...",
        "thumbnails": {
          "default": {
            "url": "https://i.ytimg.com/vi/apsAw6pzK8k/default.jpg",
            "width": 120,
            "height": 90
          },
          "medium": {
            "url": "https://i.ytimg.com/vi/apsAw6pzK8k/mqdefault.jpg",
            "width": 320,
            "height": 180
          },
          "high": {
            "url": "https://i.ytimg.com/vi/apsAw6pzK8k/hqdefault.jpg",
            "width": 480,
            "height": 360
          }
        },
        "channelTitle": "justinLITE",
        "liveBroadcastContent": "none",
        "publishTime": "2020-11-27T15:15:00Z"
      }
    },
    {
      "kind": "youtube#searchResult",
      "etag": "JA3RfxF6EBqBmmNRxsedtOKMcJs",
      "id": {
        "kind": "youtube#video",
        "videoId": "MPbUaIZAaeA"
      },
      "snippet": {
        "publishedAt": "2020-11-20T05:00:11Z",
        "channelId": "UC4-TgOSMJHn-LtY4zCzbQhw",
        "title": "Shawn Mendes, Justin Bieber - Monster",
        "description": "Listen to “Monster” now: https://Monster.lnk.to/Single New album WONDER from Shawn Mendes available Dec 4th Pre-order now: https://wonder.lnk.to/Album ...",
        "thumbnails": {
          "default": {
            "url": "https://i.ytimg.com/vi/MPbUaIZAaeA/default.jpg",
            "width": 120,
            "height": 90
          },
          "medium": {
            "url": "https://i.ytimg.com/vi/MPbUaIZAaeA/mqdefault.jpg",
            "width": 320,
            "height": 180
          },
          "high": {
            "url": "https://i.ytimg.com/vi/MPbUaIZAaeA/hqdefault.jpg",
            "width": 480,
            "height": 360
          }
        },
        "channelTitle": "ShawnMendesVEVO",
        "liveBroadcastContent": "none",
        "publishTime": "2020-11-20T05:00:11Z"
      }
    },
    {
      "kind": "youtube#searchResult",
      "etag": "HxnPWxJ157hcm5oisVd5m8d6AuA",
      "id": {
        "kind": "youtube#channel",
        "channelId": "UCIwFjwMjI0y7PDBVEO9-bkQ"
      },
      "snippet": {
        "publishedAt": "2007-01-15T21:17:27Z",
        "channelId": "UCIwFjwMjI0y7PDBVEO9-bkQ",
        "title": "Justin Bieber",
        "description": "Help change the world. http://monster.lnk.to/single.",
        "thumbnails": {
          "default": {
            "url": "https://yt3.ggpht.com/ytc/AAUvwnjpa2md8Bfk-LdYllfDdWWdF6CpKebvAlI5NifS6Q=s88-c-k-c0xffffffff-no-rj-mo"
          },
          "medium": {
            "url": "https://yt3.ggpht.com/ytc/AAUvwnjpa2md8Bfk-LdYllfDdWWdF6CpKebvAlI5NifS6Q=s240-c-k-c0xffffffff-no-rj-mo"
          },
          "high": {
            "url": "https://yt3.ggpht.com/ytc/AAUvwnjpa2md8Bfk-LdYllfDdWWdF6CpKebvAlI5NifS6Q=s800-c-k-c0xffffffff-no-rj-mo"
          }
        },
        "channelTitle": "Justin Bieber",
        "liveBroadcastContent": "upcoming",
        "publishTime": "2007-01-15T21:17:27Z"
      }
    },
    {
      "kind": "youtube#searchResult",
      "etag": "W8Plz-NvW5Wu10V8eYId5iFo_QU",
      "id": {
        "kind": "youtube#video",
        "videoId": "xQOO2xGQ1Pc"
      },
      "snippet": {
        "publishedAt": "2020-10-16T04:00:08Z",
        "channelId": "UCHkj014U2CQ2Nv0UZeYpE_A",
        "title": "Justin Bieber &amp; benny blanco - Lonely (Official Music Video)",
        "description": "Lonely is out now: http://smarturl.it/imsolonely Starring Jacob Tremblay and directed by Jake Schreier If you're feeling Lonely or know someone who is struggling ...",
        "thumbnails": {
          "default": {
            "url": "https://i.ytimg.com/vi/xQOO2xGQ1Pc/default.jpg",
            "width": 120,
            "height": 90
          },
          "medium": {
            "url": "https://i.ytimg.com/vi/xQOO2xGQ1Pc/mqdefault.jpg",
            "width": 320,
            "height": 180
          },
          "high": {
            "url": "https://i.ytimg.com/vi/xQOO2xGQ1Pc/hqdefault.jpg",
            "width": 480,
            "height": 360
          }
        },
        "channelTitle": "JustinBieberVEVO",
        "liveBroadcastContent": "none",
        "publishTime": "2020-10-16T04:00:08Z"
      }
    },
    {
      "kind": "youtube#searchResult",
      "etag": "UBm6g6muHKP8ax-leC622ZCX-Sw",
      "id": {
        "kind": "youtube#video",
        "videoId": "8EJ3zbKTWQ8"
      },
      "snippet": {
        "publishedAt": "2020-01-04T17:00:11Z",
        "channelId": "UCHkj014U2CQ2Nv0UZeYpE_A",
        "title": "Justin Bieber - Yummy (Official Video)",
        "description": "Changes Out Now: https://justinbieber.lnk.to/Changes Follow Justin: http://facebook.com/justinbieber http://twitter.com/justinbieber ...",
        "thumbnails": {
          "default": {
            "url": "https://i.ytimg.com/vi/8EJ3zbKTWQ8/default.jpg",
            "width": 120,
            "height": 90
          },
          "medium": {
            "url": "https://i.ytimg.com/vi/8EJ3zbKTWQ8/mqdefault.jpg",
            "width": 320,
            "height": 180
          },
          "high": {
            "url": "https://i.ytimg.com/vi/8EJ3zbKTWQ8/hqdefault.jpg",
            "width": 480,
            "height": 360
          }
        },
        "channelTitle": "JustinBieberVEVO",
        "liveBroadcastContent": "none",
        "publishTime": "2020-01-04T17:00:11Z"
      }
    }
  ]
}

Gson

来源：https://stackoverflow.com/questions/65043731/kotlin-gson-fromjson-returns-null

1条答案

按热度按时间

mrfwxfqh1#

在我的例子中，在app/build.gradle文件中，在buildTypes部分下，我将shrinkResources和minifyEnabled键设置为true。为了使gson库正常工作，我必须注解它们或将它们设置为false。当它们被设置为true时，gson库中的fromJson方法总是返回null。

buildTypes {
    release {
        debuggable false
        // shrinkResources true // Breaks gson library
        // minifyEnabled true // Breaks gson library
        zipAlignEnabled true

        signingConfig signingConfigs.release
    }

    debug {
        debuggable true
        // shrinkResources true // Breaks gson library
        // minifyEnabled true // Breaks gson library
        zipAlignEnabled true

        signingConfig signingConfigs.release
    }
}

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Kotlin：Gson.fromJson()返回空值

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