Question

我正在调用天气 API 并取回您在下方看到的 HourlyResponse。 hourly 字段将一组 JSON 对象映射到我尝试使用 Room 存储的 HourWeatherEntry 实体类列表。现在，在我的 RoomDatabase 实现中，我已经指定了用于 HourWeatherEntry 类的 List<Weather> 字段的自定义类型转换器，尽管如此，我还是收到了粘贴在下面的 SerializationException。我错过了什么，转换器不应该足够吗？为什么我还需要为类本身定义 Weather 类的序列化方法？

HourlyResponse.kt：

data class HourlyResponse(
    val hourly: List<HourWeatherEntry>,
    val lat: Double,
    val lon: Double,
    val timezone: String
)

HourWeatherEntry.kt

@Entity(tableName = "hour_weather")
data class HourWeatherEntry(
    @SerializedName("weather")
    val weatherInfo: List<Weather>,
    @SerializedName("temp")
    val temperature: Double,
    @SerializedName("dt")
    val time: Long
) {
    @PrimaryKey(autoGenerate = true)
    var id:Int = 0
    var icon: String? = null

    init {
        icon = weatherInfo[0].icon
    }
}

天气.kt：

data class Weather(
    val description: String,
    val icon: String,
    val id: Int,
    val main: String
)

转换器.kt：

class Converters {
    val gson = Gson()

    @TypeConverter
    fun weatherToString(weather: Weather): String = gson.toJson(weather)

    @TypeConverter
    fun weatherFromString(json: String): Weather = gson.fromJson(json, Weather::class.java)

    @TypeConverter
    fun fromWeatherList(value: List<Weather>): String = gson.toJson(value)

    @TypeConverter
    fun toWeatherList(value: String): List<Weather> = Json.decodeFromString(value)
}

预测数据库.kt：

@Database(
    entities = [CurrentWeatherEntry::class, HourWeatherEntry::class, WeekDayWeatherEntry::class, WeatherLocation::class],
    version = 1
)
@TypeConverters(Converters::class)
abstract class ForecastDatabase : RoomDatabase() {
    abstract fun currentWeatherDao(): CurrentWeatherDao
    abstract fun hourWeatherDao(): HourWeatherDao
    abstract fun weekDayWeatherDao(): WeekDayWeatherDao
    abstract fun weatherLocationDao(): WeatherLocationDao

    // Used to make sure that the ForecastDatabase class will be a singleton
    companion object {
        // Volatile == all of the threads will have immediate access to this property
        @Volatile
        private var instance: ForecastDatabase? = null
        private val LOCK = Any() // dummy object for thread monitoring

        operator fun invoke(context: Context) = instance ?: synchronized(LOCK) {
            // If the instance var hasn't been initialized, call buildDatabase()
            // and assign it the returned object from the function call (it)
            instance ?: buildDatabase(context).also { instance = it }
        }

        /**
         * Creates an instance of the ForecastDatabase class
         * using Room.databaseBuilder().
         */
        private fun buildDatabase(context: Context) =
            Room.databaseBuilder(
                context.applicationContext,
                ForecastDatabase::class.java, "forecast.db"
            )
                //.addMigrations(MIGRATION_2_3) // specify an explicit Migration Technique
                .fallbackToDestructiveMigration()
                .build()
    }
}

异常日志：

java.lang.RuntimeException: Exception while computing database live data.
        at androidx.room.RoomTrackingLiveData$1.run(RoomTrackingLiveData.java:92)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:923)
     Caused by: kotlinx.serialization.SerializationException: Serializer for class 'Weather' is not found.
    Mark the class as @Serializable or provide the serializer explicitly.
        at kotlinx.serialization.internal.Platform_commonKt.serializerNotRegistered(Platform.common.kt:91)
        at kotlinx.serialization.internal.PlatformKt.platformSpecificSerializerNotRegistered(Platform.kt:29)
        at kotlinx.serialization.SerializersKt__SerializersKt.serializer(Serializers.kt:60)
        at kotlinx.serialization.SerializersKt.serializer(Unknown Source:1)
        at kotlinx.serialization.SerializersKt__SerializersKt.builtinSerializer$SerializersKt__SerializersKt(Serializers.kt:96)
        at kotlinx.serialization.SerializersKt__SerializersKt.serializerByKTypeImpl$SerializersKt__SerializersKt(Serializers.kt:84)
        at kotlinx.serialization.SerializersKt__SerializersKt.serializer(Serializers.kt:59)
        at kotlinx.serialization.SerializersKt.serializer(Unknown Source:1)
        at com.nesoinode.flogaweather.model.network.typeconverters.Converters.toWeatherList(Converters.kt:25)
        at com.nesoinode.flogaweather.model.db.dao.HourWeatherDao_Impl$3.call(HourWeatherDao_Impl.java:115)
        at com.nesoinode.flogaweather.model.db.dao.HourWeatherDao_Impl$3.call(HourWeatherDao_Impl.java:99)
        at androidx.room.RoomTrackingLiveData$1.run(RoomTrackingLiveData.java:90)
            ... 3 more

尽管使用自定义 TypeConverters 仍获得 SerializationException

0 个答案: