Android Kotlin Dagger2提供gson：指定为非null的参数为null

我想提供一个单独的gson实例，所以我在我的NetworkModule中提供它，当我创建改装api时，gson是非null，但是当我在改装类中使用gson实例时，它是null .

@Module
    class NetworkModule {

        @Provides
        @Singleton
        fun provideGson(): Gson {
            return Gson()
        }

        @Provides
        @Singleton
        fun provideMyEnterpriseApi(gson: Gson): MyEnterpriseApi {

            //HERE GSON IS NOT NULL

            return RetrofitMyEnterpriseApi(BuildConfig.API_MYENTERPRISE_URL,
                    BuildConfig.API_MYENTERPRISE_CONNECTION_TIMEOUT,


       BuildConfig.API_MYENTERPRISE_READ_TIMEOUT,
                gson)
    }
}

我的改装api类：

class RetrofitMyEnterpriseApi(baseUrl: String, connectTimeout: Long, readTimeout: Long, private val gson: Gson)
    : RetrofitApi<RetrofitMyEnterpriseCalls>(baseUrl, connectTimeout, readTimeout, RetrofitMyEnterpriseCalls::class.java) {

    override fun buildRetrofit(baseUrl: String, connectTimeout: Long, readTimeout: Long): Retrofit {
        val builder = Retrofit.Builder()

        builder.baseUrl(baseUrl)
        builder.client(buildClient(connectTimeout, readTimeout))
        builder.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
        builder.addConverterFactory(GsonConverterFactory.create(gson))

        return builder.build()
    }

    private fun buildClient(connectTimeout: Long, readTimeout: Long): OkHttpClient {

        //HERE GSON IS NULL

        return OkHttpClient.Builder()
                .addInterceptor(OAuth2Interceptor(gson, this))
                .addInterceptor(LoggingInterceptor.newInstance())
                .connectTimeout(connectTimeout, TimeUnit.MILLISECONDS)
                .readTimeout(readTimeout, TimeUnit.MILLISECONDS)
                .build()
    }
}

RetrofitApi类：

abstract class RetrofitApi<C>
(baseUrl: String, connectTimeout: Long, readTimeout: Long, callsClass: Class<C>) {

    protected val calls: C

    init {
        val retrofit = buildRetrofit(baseUrl, connectTimeout, readTimeout)

        calls = retrofit.create(callsClass)
    }

    protected abstract fun buildRetrofit(baseUrl: String, connectTimeout: Long, readTimeout: Long): Retrofit
}

所以，当我提供它不是null时，但是当我在buildClient方法中使用它是null时，我不明白为什么，我想念Kotlin中的某些东西 .