java - Kotlin中如何设计减少冗余类？

Question

我正在学习示例“Kotlin for Android Developers(书籍)”，地址:https://github.com/antoniolg/Kotlin-for-Android-Developers

不同的kt文件中有三个类，我认为这三个类是相似的，并且这些多个类使程序变得复杂。

如何重新设计项目框架，让项目更加清晰？

DbClasses.kt

class DayForecast(var map: MutableMap<String, Any?>) {
    var _id: Long by map
    var date: Long by map
    var description: String by map
    var high: Int by map
    var low: Int by map
    var iconUrl: String by map
    var cityId: Long by map

    constructor(date: Long, description: String, high: Int, low: Int, iconUrl: String, cityId: Long)
            : this(HashMap()) {
        this.date = date
        this.description = description
        this.high = high
        this.low = low
        this.iconUrl = iconUrl
        this.cityId = cityId
    }
}

tables.kt

object DayForecastTable {
    val NAME = "DayForecast"
    val ID = "_id"
    val DATE = "date"
    val DESCRIPTION = "description"
    val HIGH = "high"
    val LOW = "low"
    val ICON_URL = "iconUrl"
    val CITY_ID = "cityId"
}

DomainClasses.kt

data class Forecast(
    val id: Long,
    val date: Long,
    val description: String,
    val high: Int, 
    val low: Int,
    val iconUrl: String
)

Answer 1

就数据库相关类而言，您可能会考虑使用 ORM 库来注释字段并生成数据库表模式(无需 DayForecastTable)，例如房间(https://developer.android.com/training/data-storage/room/index.html)

从技术上讲，您可以在整个应用程序中使用这些类来减少对 DomainClasses 的需求，尽管我建议保留域层类以使域模型独立于数据库。