查询返回的列没有字段

Question

我保留了一份按“顺序”排列的产品清单。当我试着从房间里拿一份产品清单的时候。我得到以下错误。但我做了一个TypeConvertor。会有什么错误呢？

订单

   @Entity(tableName = Order.TABLE_NAME)
@JsonClass(generateAdapter = true)
data class Order(
    @PrimaryKey(autoGenerate = true)
    val id: Long,
    val isSendCheque: Int,
    val phone: String,
    val name: String,
    val comment: String? = "",
    val timeFrom: String,
    val timeTo: String,
    @TypeConverters(Converters::class)
    @ColumnInfo(name = "listProduct")
    var listProduct: List<Product>? = null,
    val publicOrderId: String
) {
    companion object {
        const val TABLE_NAME = "mau_order"
    }
}

产品

@Parcelize
@JsonClass(generateAdapter = true)
data class Product(
        @SerializedName("id")
        @PrimaryKey
        var id: Long = -1,
        @SerializedName("order_id") var orderId: Long = -1,
        @SerializedName("name") var name: String = "name product",
        @SerializedName("packaging") var packaging: String? = "1 кг",
        @SerializedName("path_image") var pathImage: String = "",
        @SerializedName("price") var price: Double = 0.0,
        @SerializedName("price_discount") var priceDiscount: Double = 0.0,
        @SerializedName("product_id") var productId: Int = -1,
        @SerializedName("quantity") var quantity: Double = 0.0,
        @SerializedName("units") var units: String = "ШТ",
        @SerializedName("created_at") var createdAt: String = "",
        @SerializedName("updated_at") var updatedAt: String = "",
        @SerializedName("brgew") var brgew: String = "",
        @SerializedName("gewei") var gewei: String = "кг"
) : Parcelable

命令道

   @Dao
interface OrdersDao {
    /**
     * Inserts [orders] into the [Order.TABLE_NAME] table.
     * Duplicate values are replaced in the table.
     * @param orders Orders
     */
    @Insert(onConflict = OnConflictStrategy.REPLACE)
    suspend fun insertOrders(orders: List<Order>)
    /**
     * Inserts [orders] into the [Order.TABLE_NAME] table.
     * Duplicate values are replaced in the table.
     * @param orders Orders
     */
    @Insert(onConflict = OnConflictStrategy.REPLACE)
    suspend fun insertOrders(order: Order)

    /**
     * Deletes all the orders from the [Order.TABLE_NAME] table.
     */
    @Query("DELETE FROM ${Order.TABLE_NAME}")
    suspend fun deleteAllOrders()

    /**
     * Fetches the order from the [Order.TABLE_NAME] table whose id is [orderId].
     * @param orderId Unique ID of [Order]
     * @return [Flow] of [Order] from database table.
     */
    @Query("SELECT * FROM ${Order.TABLE_NAME} WHERE ID = :orderId")
    fun getOrderById(orderId: Long): LiveData<Order>

    //ERROR
    @Query("SELECT listProduct FROM ${Order.TABLE_NAME} WHERE ID = :orderId")
    fun getBasketById(orderId: Long): LiveData<Order>

    /**
     * Fetches all the orders from the [Order.TABLE_NAME] table.
     * @return [Flow]
     */
    @Query("SELECT * FROM ${Order.TABLE_NAME}")
    fun getAllOrders(): LiveData<List<Order>>
}

转换器

 @TypeConverter
fun stringToProductList(data: String?): MutableList<Product> {
    if (data == null) {
        return Collections.emptyList()
    }

    val listType = object : TypeToken<MutableList<Product>>() {

    }.type

    return gson.fromJson(data, listType)
}

@TypeConverter
fun ProductListToString(someObjects: MutableList<Product>?): String? {
    if (someObjects == null) {
        return null
    }
    return gson.toJson(someObjects)
}

错误

java：53：错误：查询返回的列在com.vepe.navigation.model.entity.product中没有字段[id,orderId,name,pathImage,price,priceDiscount,productId,quantity,units,createdAt,updatedAt,brgew,gewe],即使这些字段被注释为非空或原语。查询返回的列:[listProduct]public abstract java.util.list getBasketHistoryFromOrderById（长orderId）；当前的JDK版本1.8.0_272-B10有一个阻止空间增量的错误(https://bugs.openjdk.java.net/browse/jdk-8007720)。考虑使用JDK 11+或Android Studio 3.5+附带的嵌入式JDK。c:\users\mind\studioprojects\sarah_navigationproject\projectandroid\app\build\tmp\kapt3\stubs\debug\com\vepe\navigation\model\Entity\product.java:8:error：实体类必须用@Entity注释

求求你帮帮我！谢谢

更新我试着把@Entity注释，我不知道它们在我的情况下是否必要，但得到了以下错误

错误：查询返回得列在com.vepe.navigation.model.entity.product中没有字段[id,orderId,name,pathImage,price,priceDiscount,productId,quantity,units,createdAt,updatedAt,brgew,GEWE],即使这些字段被批注为非空或原语.查询返回的列:[listProduct]public abstract kotlinx.coroutines.flow.flow >getBasketHistoryFromOrderById（长orderId）；当前的JDK版本1.8.0_272-B10有一个阻止空间增量的错误(https://bugs.openjdk.java.net/browse/jdk-8007720)。考虑使用JDK 11+或Android Studio 3.5+附带的嵌入式JDK。c:\users\mind\studioprojects\sarah_navigationproject\projectandroid\app\build\tmp\kapt3\stubs\debug\com\vepe\navigation\data\local\dao\ordersdao.java:53:警告：查询返回com.vepe.navigation.model.entity.product没有使用的一些列[listProduct]。您可以在字段上使用@ColumnInfo注释来指定映射。com.vepe.navigation.model.entity.product有一些字段[id,orderId,name,packaging,pathImage,price,priceDiscount,productId,quantity,units,createdAt,updatedAt,brgew,gewei],这些字段不由查询返回。如果不应该从结果中读取它们，您可以用@Ignore注释标记它们。您可以通过使用@SuppressWarnings(RoomWarnings.cursor_Mismatch)批注方法来取消显示此警告。查询返回的列：ListProduct。com.vepe.navigation.model.entity.product中的字段：id,orderId,name,packaging,pathImage,price,priceDiscount,productId,quantity,units,createdAt,updatedAt,brgew,GEWEI.

Answer 1

您需要修复此查询：

@Query("SELECT listProduct FROM ${Order.TABLE_NAME} WHERE ID = :orderId")
    fun getBasketById(orderId: Long): LiveData<Order>

问题是所选字段(ListProduct)与返回的类型(Order)不匹配。Room抱怨它无法理解如何构建只有一个its字段ListProduct的Order实例。

解决此问题的最简单方法是选择创建order实例所需的所有字段：

@Query("SELECT * FROM ${Order.TABLE_NAME} WHERE ID = :orderId")
    fun getBasketById(orderId: Long): LiveData<Order>

Answer 2

我想出了这个办法来解决问题

在订单服务中

@GET("orders/baskethistory/id/{id}")
suspend fun getBasketHistoryById(@Path("id") id: Long): Response<BasketHistory>

对象列表的数据类

data class BasketHistory(
    @SerializedName("basketHistory") val listProduct : MutableList<Product>
)

刀

@Query("SELECT id,listProduct FROM ${Order.TABLE_NAME} WHERE ID = :orderId")
fun getBasketById(orderId: Long): LiveData<BasketHistory>

试试看