前言
Room是对SQLite的封装，官方推荐使用Room。该文档来自google官方文档。该文档里的代码是kotlin。
适用类型转换TypeConverter
例如Date类型
1. 声明Converters
class Converters {
@TypeConverter
fun fromTimestamp(value: Long?): Date? {
return value?.let { Date(it) }
}
@TypeConverter
fun dateToTimestamp(date: Date?): Long? {
return date?.time?.toLong()
}
}
这样，当写的时候会调用dateToTimestamp，读的时候会调用fromTimestamp
2. 使用
@Database(entities = arrayOf(User::class), version = 1)
@TypeConverters(Converters::class)
abstract class AppDatabase : RoomDatabase() {
abstract fun userDao(): UserDao
}
@Entity
data class User(private var birthday: Date?)
@Dao
interface UserDao {
@Query("SELECT * FROM user WHERE birthday BETWEEN :from AND :to")
fun findUsersBornBetweenDates(from: Date, to: Date): List<User>
}
