Retrofit 2.7.2使用retrofit调用时发生GSON错误，错误为“无法调用类的无参数构造函数“,无法找到解决方案

kb5ga3dv  于 2022-11-06  发布在  其他
关注(0)|答案(1)|浏览(117)

我正在使用android studio和Kotlin，试图使用gson库进行API调用。我使用JSON到kotlin数据类插件来制作我的数据类。我已经寻找了解决方案，但还没有找到任何与我的问题完全匹配的东西。我寻找了如何在kotlin中添加一个无参数构造函数，但这涉及到将所有字段设置为默认值，这不是我想要的。我想知道它是否在调用API，但没有收到任何转换率，但我不知道如何检查，因为我立即得到抛出调用API时的错误。
我收到的确切错误是：
“无法为类com.schrader.currency_take_two.data.models.ConversionRates调用无参数构造函数。使用此类型的Gson注册InstanceCreator可能会解决此问题。”
这是我的身材

  1. plugins {
  2.     id 'com.android.application'
  3.     id 'org.jetbrains.kotlin.android'
  4.     id 'dagger.hilt.android.plugin'
  5.     id 'kotlin-kapt'
  6. }
  8. android {
  9.     compileSdk 31
  11.     defaultConfig {
  12.         applicationId "com.schrader.currency_take_two"
  13.         minSdk 21
  14.         targetSdk 31
  15.         versionCode 1
  16.         versionName "1.0"
  18.         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
  19.     }
  21.     buildTypes {
  22.         release {
  23.             minifyEnabled false
  24.             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
  25.         }
  26.     }
  27.     compileOptions {
  28.         sourceCompatibility JavaVersion.VERSION_1_8
  29.         targetCompatibility JavaVersion.VERSION_1_8
  30.     }
  31.     kotlinOptions {
  32.         jvmTarget = '1.8'
  33.     }
  35.     buildFeatures{
  36.         viewBinding true
  37.     }
  38. }
  40. dependencies {
  42.     implementation 'androidx.core:core-ktx:1.7.0'
  43.     implementation 'androidx.appcompat:appcompat:1.4.1'
  44.     implementation 'com.google.android.material:material:1.5.0'
  45.     implementation 'androidx.constraintlayout:constraintlayout:2.1.3'
  46.     testImplementation 'junit:junit:4.13.2'
  47.     androidTestImplementation 'androidx.test.ext:junit:1.1.3'
  48.     androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
  50.     // dagger-hilt
  51.     implementation 'com.google.dagger:hilt-android:2.41'
  52.     kapt 'com.google.dagger:hilt-compiler:2.41'
  54.     // retrofit
  55.     implementation 'com.squareup.retrofit2:retrofit:2.7.2'
  56.     implementation 'com.squareup.retrofit2:converter-gson:2.7.2'
  57.     implementation 'com.squareup.okhttp3:okhttp:3.6.0'
  59.     // coroutines
  60.     implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.9'
  62.     // ViewModel
  63.     def lifecycle_version = "2.4.1"
  64.     implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$lifecycle_version"
  65.     // LiveData
  66.     implementation "androidx.lifecycle:lifecycle-livedata-ktx:$lifecycle_version"
  67.     // Lifecycles only (without ViewModel or LiveData)
  68.     implementation "androidx.lifecycle:lifecycle-runtime-ktx:$lifecycle_version"
  70.     implementation "androidx.core:core-ktx:1.7.0"
  72.     //fragment KTX library
  73.     implementation "androidx.fragment:fragment-ktx:1.4.1"
  75.     implementation "androidx.activity:activity-ktx:1.4.0"
  77.     // Room DB
  78.     def room_version = "2.4.2"
  80.     implementation "androidx.room:room-runtime:$room_version"
  81.     kapt "androidx.room:room-compiler:$room_version"
  83. }

以下是数据类，其中一个在这里被缩短，因为它很长：

  1. package com.schrader.currency_take_two.data.models
  3. import com.google.gson.annotations.SerializedName
  5. data class CurrencyResponse(
  6.     @SerializedName("base_code")
  7.     val baseCode: String,
  8.     @SerializedName("conversion_rates")
  9.     val conversionRates: ConversionRates,
  10.     @SerializedName("documentation")
  11.     val documentation: String,
  12.     @SerializedName("result")
  13.     val result: String,
  14.     @SerializedName("terms_of_use")
  15.     val termsOfUse: String,
  16.     @SerializedName("time_last_update_unix")
  17.     val timeLastUpdateUnix: Int,
  18.     @SerializedName("time_last_update_utc")
  19.     val timeLastUpdateUtc: String,
  20.     @SerializedName("time_next_update_unix")
  21.     val timeNextUpdateUnix: Int,
  22.     @SerializedName("time_next_update_utc")
  23.     val timeNextUpdateUtc: String
  24. )
  26. package com.schrader.currency_take_two.data.models
  28. import com.google.gson.annotations.SerializedName
  30. data class ConversionRates(
  31.     @SerializedName("AED")
  32.     val aED: Double,
  33.     @SerializedName("AFN")
  34.     val aFN: Double,
  35.     @SerializedName("ALL")
  36.     val aLL: Double,
  37.     @SerializedName("AMD")
  38.     val aMD: Double,
  39.     @SerializedName("ANG")
  40.     val aNG: Double,
  41.     @SerializedName("AOA")
  42.     val aOA: Double,
  43.     @SerializedName("ARS")
  44.     val aRS: Double
  45. )

下面是改造调用和我的改造示例：

  1. interface CurrencyApi {
  3.     @GET("/v6/API_KEY/latest/{Currency}")
  4.     suspend fun getRates(
  5.         @Path("Currency") currency: String //This adds onto the API URL in the {} in the GET, @Query adds a query to the URL 'Query={Query}'
  6.     ): Response<CurrencyResponse>
  7. }

API调用没有到达第一个Log调用，并且立即错误出到catch块。
第一个
下面是我在主Activity中调用API的方式：

  1. GlobalScope.launch(Dispatchers.IO){
  2.                var response = apiRepo.getRates("USD")
  3.                if(response.data == null){
  4.                    Log.d("MAIN", "${response.message}")
  5.                }
  6.                Log.d("MAIN", "${response.toString()}")
  7.             }

下面是来自API的确切JSON：

  1. {
  2.  "result":"success",
  3.  "documentation":"https://www.exchangerate-api.com/docs",
  4.  "terms_of_use":"https://www.exchangerate-api.com/terms",
  5.  "time_last_update_unix":1649203202,
  6.  "time_last_update_utc":"Wed, 06 Apr 2022 00:00:02 +0000",
  7.  "time_next_update_unix":1649289602,
  8.  "time_next_update_utc":"Thu, 07 Apr 2022 00:00:02 +0000",
  9.  "base_code":"USD",
  10.  "conversion_rates":{
  11.   "USD":1,
  12.   "AED":3.6725,
  13.   "AFN":88.6534,
  14.   "ALL":110.0838,
  15.   "AMD":480.1007,
  16.   "ANG":1.7900,
  17.   "AOA":445.0124,
  18.   "ARS":111.4453,
  19.   "AUD":1.3155,
  20.   "AWG":1.7900,
  21.   "AZN":1.6961,
  22.   "BAM":1.7892,
  23.   "BBD":2.0000,
  24.   "BDT":85.2904,
  25.   "BGN":1.7884,
  26.   "BHD":0.3760,
  27.   "BIF":2005.2598,
  28.   "BMD":1.0000,
  29.   "BND":1.3581,
  30.   "BOB":6.8635,
  31.   "BRL":4.6151,
  32.   "BSD":1.0000,
  33.   "BTN":75.3175,
  34.   "BWP":11.5278,
  35.   "BYN":2.8692,
  36.   "BZD":2.0000,
  37.   "CAD":1.2468,
  38.   "CDF":1995.8399,
  39.   "CHF":0.9283,
  40.   "CLP":779.3730,
  41.   "CNY":6.3692,
  42.   "COP":3716.7222,
  43.   "CRC":660.0122,
  44.   "CUP":24.0000,
  45.   "CVE":100.8701,
  46.   "CZK":22.2978,
  47.   "DJF":177.7210,
  48.   "DKK":6.8247,
  49.   "DOP":54.9168,
  50.   "DZD":143.1850,
  51.   "EGP":18.2463,
  52.   "ERN":15.0000,
  53.   "ETB":51.2293,
  54.   "EUR":0.9148,
  55.   "FJD":2.0753,
  56.   "FKP":0.7634,
  57.   "FOK":6.8247,
  58.   "GBP":0.7634,
  59.   "GEL":3.0853,
  60.   "GGP":0.7634,
  61.   "GHS":7.7634,
  62.   "GIP":0.7634,
  63.   "GMD":54.8016,
  64.   "GNF":8946.2447,
  65.   "GTQ":7.6691,
  66.   "GYD":209.6041,
  67.   "HKD":7.8373,
  68.   "HNL":24.5487,
  69.   "HRK":6.8925,
  70.   "HTG":107.4322,
  71.   "HUF":341.7488,
  72.   "IDR":14374.8444,
  73.   "ILS":3.2117,
  74.   "IMP":0.7634,
  75.   "INR":75.3200,
  76.   "IQD":1462.3970,
  77.   "IRR":41938.4058,
  78.   "ISK":129.1085,
  79.   "JEP":0.7634,
  80.   "JMD":153.5796,
  81.   "JOD":0.7090,
  82.   "JPY":123.3508,
  83.   "KES":115.6196,
  84.   "KGS":85.8864,
  85.   "KHR":4057.0179,
  86.   "KID":1.3156,
  87.   "KMF":450.0508,
  88.   "KRW":1215.3051,
  89.   "KWD":0.2996,
  90.   "KYD":0.8333,
  91.   "KZT":466.7579,
  92.   "LAK":13220.0876,
  93.   "LBP":1507.5000,
  94.   "LKR":295.1163,
  95.   "LRD":152.7083,
  96.   "LSL":14.6202,
  97.   "LYD":4.6812,
  98.   "MAD":9.4783,
  99.   "MDL":18.3389,
  100.   "MGA":3035.6361,
  101.   "MKD":56.0557,
  102.   "MMK":1825.6103,
  103.   "MNT":2954.7230,
  104.   "MOP":8.0723,
  105.   "MRU":36.4708,
  106.   "MUR":44.3148,
  107.   "MVR":15.4209,
  108.   "MWK":820.4555,
  109.   "MXN":19.9358,
  110.   "MYR":4.2051,
  111.   "MZN":64.2611,
  112.   "NAD":14.6202,
  113.   "NGN":415.4445,
  114.   "NIO":35.8669,
  115.   "NOK":8.7398,
  116.   "NPR":120.5080,
  117.   "NZD":1.4357,
  118.   "OMR":0.3845,
  119.   "PAB":1.0000,
  120.   "PEN":3.6681,
  121.   "PGK":3.5228,
  122.   "PHP":51.2574,
  123.   "PKR":183.8781,
  124.   "PLN":4.2286,
  125.   "PYG":7064.7743,
  126.   "QAR":3.6400,
  127.   "RON":4.5173,
  128.   "RSD":107.6495,
  129.   "RUB":83.3695,
  130.   "RWF":1058.3464,
  131.   "SAR":3.7500,
  132.   "SBD":7.8290,
  133.   "SCR":14.3972,
  134.   "SDG":445.3390,
  135.   "SEK":9.4126,
  136.   "SGD":1.3582,
  137.   "SHP":0.7634,
  138.   "SLL":11827.2387,
  139.   "SOS":579.5740,
  140.   "SRD":20.7475,
  141.   "SSP":425.3169,
  142.   "STN":22.4125,
  143.   "SYP":2511.1358,
  144.   "SZL":14.6202,
  145.   "THB":33.5163,
  146.   "TJS":12.5014,
  147.   "TMT":3.5000,
  148.   "TND":2.7588,
  149.   "TOP":2.2203,
  150.   "TRY":14.7205,
  151.   "TTD":6.7529,
  152.   "TVD":1.3156,
  153.   "TWD":28.6146,
  154.   "TZS":2322.3918,
  155.   "UAH":29.1999,
  156.   "UGX":3547.1133,
  157.   "UYU":41.2934,
  158.   "UZS":11432.7976,
  159.   "VES":4.4095,
  160.   "VND":22865.8925,
  161.   "VUV":110.6141,
  162.   "WST":2.5488,
  163.   "XAF":600.0677,
  164.   "XCD":2.7000,
  165.   "XDR":0.7277,
  166.   "XOF":600.0677,
  167.   "XPF":109.1646,
  168.   "YER":250.3338,
  169.   "ZAR":14.6364,
  170.   "ZMW":17.6268,
  171.   "ZWL":142.3748
  172.  }
  173. }
Gson

1条答案

按热度按时间
ttisahbt

ttisahbt1#

您需要初始化它们。原因之一可能是值为null。

  1. data class CurrencyResponse(
  2.     @SerializedName("base_code")
  3.     val baseCode: String? = null,
  4.     @SerializedName("conversion_rates")
  5.     val conversionRates: ConversionRates? = null,
  6.     @SerializedName("documentation")
  7.     val documentation: String? = null,
  8.     @SerializedName("result")
  9.     val result: String? = null,
  10.     @SerializedName("terms_of_use")
  11.     val termsOfUse: String? = null,
  12.     @SerializedName("time_last_update_unix")
  13.     val timeLastUpdateUnix: Int? = null,
  14.     @SerializedName("time_last_update_utc")
  15.     val timeLastUpdateUtc: String? = null,
  16.     @SerializedName("time_next_update_unix")
  17.     val timeNextUpdateUnix: Int? = null,
  18.     @SerializedName("time_next_update_utc")
  19.     val timeNextUpdateUtc: String? = null
  20. )
展开查看全部
赞(0）分享  回复(0）举报  2022-11-06
我来回答

相关问题

    查看更多

    热门标签

    更多
    JavaquerypythonNode开发语言requestUtil数据库Table后端算法LoggerMessageElementParser

    最新问答

    更多
    • 蜀ICP备13028337号-1 大数据知识库 https://www.saoniuhuo.com © All rights reserved
    • 本站内容来源互联网,如果侵犯您的权益请联系我们删除, 联系方式：448109455@qq.com