Android 当初始化改装时，我得到错误：KotlinNullPointerException

这里是RestClientFactory.kt

class TransportService {
    companion object {
        private val waitressCallRestClient =  RestClientFactory.createRestClient(WaitressCallRestClient::class.java)

        private val TAG = TransportService::class.java.name

        init {
            Debug.d(TAG, "TransportService_initialize")
       }
    }
}

错误：

.addConverterFactory(GsonConverterFactory.create(gson!!))

11-08 13:26:58.104 E/AndroidRuntime（13653）：致命异常：主
11-08 13:26:58.104 E/AndroidRuntime（13653）：进程：com.myproject.android.debug，PID:13653
11-08 13:26:58.104 E/AndroidRuntime（13653）：java.lang.ExceptionInInitializeError
11-08 13:26:58.104 E/AndroidRuntime（13653）：在com.myproject.android.service.TransportService.（TransportService.kt:25）
11-08 13:26:58.104 E/AndroidRuntime（13653）：在com.myproject.android.viewmodel.FeedbackViewModel$doClickSend$1.invokeSuspend（FeedbackViewModel.kt:39）
11-08 13:26:58.104 E/AndroidRuntime（13653）：在kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith（ContinuationImpl.kt:33）
11-08 13:26:58.104 E/AndroidRuntime（13653）：在kotlinx.coroutines.DispatchedTask.run（Dispatched.kt:241）
11-08 13:26:58.104 E/AndroidRuntime（13653）：在android.os.Handler.handleCallback（Handler.java:739）
11-08 13:26:58.104 E/AndroidRuntime（13653）：在android.os.Handler.dispatchMessage（Handler.java:95）上
11-08 13:26:58.104 E/AndroidRuntime（13653）：在android.os.Looper.loop（Looper.java:148）
11-08 13:26:58.104 E/AndroidRuntime（13653）：位于android.app.ActivityThread.main（ActivityThread.java:5417）
11-08 13:26:58.104 E/AndroidRuntime（13653）：位于java.lang.reflect.Method.invoke（本机方法）
11-08 13:26:58.104 E/AndroidRuntime（13653）：在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run（ZygoteInit.java:726）
11-08 13:26:58.104 E/AndroidRuntime（13653）：位于com.android.internal.os.ZygoteInit.main（ZygoteInit.java:616）
11-08 13:26:58.104 E/AndroidRuntime（13653）：由以下原因引起：kotlin.KotlinNullPointerException
11-08 13:26:58.104 E/AndroidRuntime（13653）：在com.myproject.android.api.RestClientFactory.（RestClientFactory.kt:40）
11-08 13:26:58.104 E/AndroidRuntime（13653）：。。。还有11个

更换

11-08 13:26:58.104 E/AndroidRuntime(13653): FATAL EXCEPTION: main
11-08 13:26:58.104 E/AndroidRuntime(13653): Process: com.myproject.android.debug, PID: 13653
11-08 13:26:58.104 E/AndroidRuntime(13653): java.lang.ExceptionInInitializerError
11-08 13:26:58.104 E/AndroidRuntime(13653):     at com.myproject.android.service.TransportService.<clinit>(TransportService.kt:25)
11-08 13:26:58.104 E/AndroidRuntime(13653):     at com.myproject.android.viewmodel.FeedbackViewModel$doClickSend$1.invokeSuspend(FeedbackViewModel.kt:39)
11-08 13:26:58.104 E/AndroidRuntime(13653):     at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
11-08 13:26:58.104 E/AndroidRuntime(13653):     at kotlinx.coroutines.DispatchedTask.run(Dispatched.kt:241)
11-08 13:26:58.104 E/AndroidRuntime(13653):     at android.os.Handler.handleCallback(Handler.java:739)
11-08 13:26:58.104 E/AndroidRuntime(13653):     at android.os.Handler.dispatchMessage(Handler.java:95)
11-08 13:26:58.104 E/AndroidRuntime(13653):     at android.os.Looper.loop(Looper.java:148)
11-08 13:26:58.104 E/AndroidRuntime(13653):     at android.app.ActivityThread.main(ActivityThread.java:5417)
11-08 13:26:58.104 E/AndroidRuntime(13653):     at java.lang.reflect.Method.invoke(Native Method)
11-08 13:26:58.104 E/AndroidRuntime(13653):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
11-08 13:26:58.104 E/AndroidRuntime(13653):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
11-08 13:26:58.104 E/AndroidRuntime(13653): Caused by: kotlin.KotlinNullPointerException
11-08 13:26:58.104 E/AndroidRuntime(13653):     at com.myproject.android.api.RestClientFactory.<clinit>(RestClientFactory.kt:40)
11-08 13:26:58.104 E/AndroidRuntime(13653):     ... 11 more

到

---

httpClient

和

gson

为空，您永远不会初始化它们

---

停止使用

编译器会告诉您；）
 您需要初始化Gson对象

Gson Gson=new GsonBuilder（）
.setLenient（）
.create（）；
我改成这样，现在开始工作：

   1) try using this, If you do not want to use gson in this class

        private var retrofit: Retrofit? = null
         retrofit = Retrofit.Builder()
                        .baseUrl(BASE_URL)
                        .client(httpClient.build())
                        .addConverterFactory(GsonConverterFactory.create())
                        .build()

    2) or if you want to use gson here then below code may help you :
    Gson gson = new GsonBuilder()
         .registerTypeAdapter(Id.class, new IdTypeAdapter())
         .enableComplexMapKeySerialization()
         .serializeNulls()
         .setDateFormat(DateFormat.LONG)
         .setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE)
         .setPrettyPrinting()
         .setVersion(1.0)
         .create();
        Retrofit retrofit = new Retrofit.Builder()  
         .baseUrl(BASE_URL)
         .addConverterFactory(GsonConverterFactory.create(gson))
         .build();

您的
var gson
为空且从未分配给，您执行了不安全的非空强制转换
gson。您忘记初始化gson
var gson:gson？=空
.addConverterFactory(GsonConverterFactory.create(gson!!))

.addConverterFactory(GsonConverterFactory.create(GsonBuilder().setLenient().create()))

   1) try using this, If you do not want to use gson in this class

        private var retrofit: Retrofit? = null
         retrofit = Retrofit.Builder()
                        .baseUrl(BASE_URL)
                        .client(httpClient.build())
                        .addConverterFactory(GsonConverterFactory.create())
                        .build()

    2) or if you want to use gson here then below code may help you :
    Gson gson = new GsonBuilder()
         .registerTypeAdapter(Id.class, new IdTypeAdapter())
         .enableComplexMapKeySerialization()
         .serializeNulls()
         .setDateFormat(DateFormat.LONG)
         .setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE)
         .setPrettyPrinting()
         .setVersion(1.0)
         .create();
        Retrofit retrofit = new Retrofit.Builder()  
         .baseUrl(BASE_URL)
         .addConverterFactory(GsonConverterFactory.create(gson))
         .build();

object RestClientFactory {
    private val gsonBuilder = GsonUtil.gsonbuilder
    private var gson: Gson
    private val CONNECTION_TIME_OUT_SEC = 60
    private val READ_TIME_OUT_SEC = 60
    private val WRITE_TIME_OUT_SEC = 60
    private var httpClient: OkHttpClient.Builder
    private val httpLoggingInterceptor =
        HttpLoggingInterceptor().setLevel(HttpLoggingInterceptor.Level.BODY)

    private val TAG = RestClientFactory::class.java.name

    init {
        Debug.d(TAG, "static_initializer: START_GSON_setting!")
        gson = gsonBuilder.create();
        gsonBuilder.setDateFormat(DateUtil.TO_FO_DATETIME_FORMAT)
        // default timeout = 10 sec
        httpClient = OkHttpClient.Builder() // default timeout = 10 sec
            .connectTimeout(CONNECTION_TIME_OUT_SEC.toLong(), TimeUnit.SECONDS)
            .readTimeout(READ_TIME_OUT_SEC.toLong(), TimeUnit.SECONDS)
            .writeTimeout(WRITE_TIME_OUT_SEC.toLong(), TimeUnit.SECONDS)