如何在android中使用room加载db文件

我正在开发一个android应用程序。

我想用这个数据库文件作为我的android应用程序的数据库。 我试图找到任何解决办法,但找不到。

@Database(entities = [Item::class], version = 1)
@TypeConverters(ObjectConverter::class)
abstract class MyDatabase : RoomDatabase() {

    abstract fun itemDao(): ItemDao

    companion object {

        private const val DATABASE_NAME = "my.db"

        private var INSTANCE: MyDatabase? = null

        private val lock = Any()

        fun getInstance(context: Context): MyDatabase {
            synchronized(lock) {
                if (INSTANCE == null) {
                    initDatabase(context, DATABASE_NAME)
                    INSTANCE = Room.databaseBuilder(context.applicationContext,
                            MyDatabase::class.java, DATABASE_NAME)
                            .addCallback(object : Callback() {
                            })
                            .build()
                }
                return INSTANCE!!
            }
        }

        private fun initDatabase(context: Context, databaseName: String) {
            val dbPath = context.getDatabasePath(databaseName)
            if (dbPath.exists()) {
                return
            }

            dbPath.parentFile.mkdirs()
            val reader = BufferedReader(context.assets.open(databaseName).reader())
            val writer = FileWriter(dbPath)

            var line: String?
            do {
                line = reader.use { readLine() }
                if (line == null)
                    break

                writer.use { it.write(line) }
            } while (true)
            writer.flush()
        }
    }
}