Android Room - "Cannot figure out how to save this field into database."

Question

I try to create Room database and insert values to it, but I got this error:

public abstract class WeatherDatabase extends androidx.room.RoomDatabase { ^error: Cannot figure out how to save this field into database. You can consider adding a type converter for it. - mDatabase in androidx.room.RoomDatabaseerror: Cannot figure out how to save this field into database. You can consider adding a type converter for it. - mCallbacks in androidx.room.RoomDatabaseerror: Cannot figure out how to save this field into database. You can consider adding a type converter for it. - mQueryExecutor in androidx.room.RoomDatabaseerror: Cannot figure out how to save this field into database. You can consider adding a type converter for it. - mTransactionExecutor in androidx.room.RoomDatabaseerror: Cannot figure out how to save this field into database. You can consider adding a type converter for it. - mOpenHelper in androidx.room.RoomDatabaseerror: Cannot figure out how to save this field into database. You can consider adding a type converter for it. - mInvalidationTracker in androidx.room.RoomDatabaseerror: Cannot figure out how to save this field into database. You can consider adding a type converter for it. - mCloseLock in androidx.room.RoomDatabaseerror: Cannot figure out how to save this field into database. You can consider adding a type converter for it. - mSuspendingTransactionId in androidx.room.RoomDatabaseerror: Cannot figure out how to save this field into database. You can consider adding a type converter for it. - mBackingFieldMap in androidx.room.RoomDatabaseerror: Cannot find getter for field. - mAllowMainThreadQueries in androidx.room.RoomDatabaseerror: Cannot find getter for field. - mCloseLock in androidx.room.RoomDatabaseerror: Cannot find getter for field. - mSuspendingTransactionId in androidx.room.RoomDatabaseerror: Cannot find getter for field. - mBackingFieldMap in androidx.room.RoomDatabaseerror: Cannot find setter for field. - mQueryExecutor in androidx.room.RoomDatabaseerror: Cannot find setter for field. - mTransactionExecutor in androidx.room.RoomDatabaseerror: Cannot find setter for field. - mOpenHelper in androidx.room.RoomDatabaseerror: Cannot find setter for field. - mInvalidationTracker in androidx.room.RoomDatabaseerror: Cannot find setter for field. - mAllowMainThreadQueries in androidx.room.RoomDatabaseerror: Cannot find setter for field. - mCloseLock in androidx.room.RoomDatabaseerror: Cannot find setter for field. - mSuspendingTransactionId in androidx.room.RoomDatabaseerror: Cannot find setter for field. - mBackingFieldMap in androidx.room.RoomDatabaseC:\Users\ceran\Desktop\Projekty\Android\SimpleWeatherApp\app\build\tmp\kapt3\stubs\debug\com\example\simpleweatherapp\database\WeatherDao.java:11: error: There is a problem with the query: [SQLITE_ERROR] SQL error or missing database (no such table: databaseweather) public abstract androidx.lifecycle.LiveData<com.example.simpleweatherapp.database.DatabaseWeather> getWeather(); ^C:\Users\ceran\Desktop\Projekty\Android\SimpleWeatherApp\app\build\tmp\kapt3\stubs\debug\com\example\simpleweatherapp\database\WeatherDao.java:14: error: com.example.simpleweatherapp.database.WeatherDao is part of com.example.simpleweatherapp.database.WeatherDatabase but this entity is not in the database. Maybe you forgot to add com.example.simpleweatherapp.database.DatabaseWeather to the entities section of the @Database?

It's long, but it's repeated the same sentence "Cannot figure out how to save this field into database. You can consider adding a type converter for it." What should I do? Here is my code:

@Entity(tableName = "current_weather")
data class DatabaseWeather constructor(
    val name: String,
    val lon: Double,
    val lat: Double,
    val description: String,
    val icon: String,
    val temp: Double,
    val tempFeelsLike: Double,
    val humidity: Int,
    val pressure: Int
){
    @PrimaryKey(autoGenerate = false)
    var id: Int = WEATHER_ID
}

fun DatabaseWeather.asDomainModel(): CurrentWeather{
    return CurrentWeather(
        name = this.name,
        lon = this.lon,
        lat = this.lat,
        description = this.description,
        icon = this.icon,
        temp = this.temp,
        tempFeelsLike = this.tempFeelsLike,
        humidity = this.humidity,
        pressure = this.pressure
    )
}

@Dao
interface WeatherDao{

    @Query("select * from current_weather where id = $WEATHER_ID")
    fun getWeather(): LiveData<DatabaseWeather>

    @Insert(onConflict = OnConflictStrategy.REPLACE)
    fun insert(weather: DatabaseWeather)
}

@Database(entities = [WeatherDatabase::class], version = 1)
abstract class WeatherDatabase: RoomDatabase(){
    abstract val weatherDao: WeatherDao
}

private lateinit var INSTANCE: WeatherDatabase

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

Answer 1

You are providing WeatherDatabase as entity for WeatherDatabase, instead provide DatabaseWeather

@Database(entities = [DatabaseWeather::class], version = 1)
abstract class WeatherDatabase: RoomDatabase(){
    abstract val weatherDao: WeatherDao
}