Question

我正在尝试为联赛数据实现房间数据库，但是当我尝试编译时，它不起作用。该错误似乎是在数据库文件中引发的。希望你能帮我

在Dao中，我选择所有countryProperty并将它们插入到数据库中，

@Dao
interface CountryDataBaseDao {
   @Query("SELECT * FROM DatabaseCountryProperty")
   fun getData() : LiveData<List<DatabaseCountryProperty>>

   @Insert(onConflict = OnConflictStrategy.REPLACE)
   fun insertData(data : List<DatabaseCountryProperty>)
}

在实体中，countryProperty 实体获得额外的实体，

@Entity
data class DatabaseCountryProperty constructor(
    @PrimaryKey
      val id: String,
      val name: String,
      val imagePath: String?,
      val extra: DatabaseExtraCountry?)


    data class DatabaseExtraCountry constructor(
      val continent : String?,
      val subRegion : String?,
      val worldRegion : String?,
      val fifa : String?,
      val iso : String?,
      val iso2 : String?,
      val longitude : Double?,
      val latitude : Double?,
      val flag : String?) {
}

fun List<DatabaseCountryProperty>.asDomainModel() : List<DevByteCountryProperty> {
    return map {
            DevByteCountryProperty(
                    id = it.id,
                    name = it.name,
                    imagePath = it.imagePath,
                    extra = DevByteExtraCountry(
                            continent = it.extra?.continent,
                            subRegion = it.extra?.subRegion,
                            worldRegion = it.extra?.worldRegion,
                            fifa = it.extra?.fifa,
                            iso = it.extra?.iso,
                            iso2 = it.extra?.iso2,
                            longitude = it.extra?.longitude,
                            latitude = it.extra?.latitude,
                            flag = it.extra?.flag
                    )
            )
    }
}

在数据库中，

@Database(entities = [DatabaseCountryProperty::class], version = 1, exportSchema = false)
   abstract class DataDataBase : RoomDatabase() {
      abstract val countryDataBaseDao : CountryDataBaseDao

   }

    private lateinit var INSTANCE: DataDataBase

    fun getDatabase(context: Context): DataDataBase {
     synchronized(DataDataBase::class.java) {
       if (!::INSTANCE.isInitialized) {
           INSTANCE = Room.databaseBuilder(context.applicationContext,
                   DataDataBase::class.java,
                   "data").build()
       }
     }
     return INSTANCE
   }

Answer 1

错误是我没有嵌入注释来声明额外的是子类的事实。所以代码是，

@Entity
data class DatabaseCountryProperty constructor(
  @PrimaryKey
  val id: String,
  val name: String,
  val imagePath: String?,
  @Embedded
  val extra: DatabaseExtraCountry?)


data class DatabaseExtraCountry constructor(
  val continent : String?,
  val subRegion : String?,
  val worldRegion : String?,
  val fifa : String?,
  val iso : String?,
  val iso2 : String?,
  val longitude : Double?,
  val latitude : Double?,
  val flag : String?) {

}

Answer 2

将这些添加到您的构建 gradle 中。

插件中的 id 'kotlin-kapt'

  kapt "androidx.room:room-compiler:2.3.0"  in your dependencies

尝试一下

Android studio kotlin 错误：任务':app:kaptDebugKotlin' 执行失败

2 个答案: