Room库无法识别我为枚举列表创建的TypeConverter.但是,当我将其更改为枚举的ArrayList时,它工作正常.任何人都知道为什么以及我该怎么做才能使这个工作与List？ (在Kotlin中使用List更容易,我真的不想因为这个原因而转换回ArrayList).

这是我的代码：

我的模特：

@H_403_6@@Entity data class Example(@PrimaryKey val id: String?,val name: String,var days: List<DayOfWeek>?)

DayOfWeek是一个枚举：

@H_403_6@enum class DayOfWeek { MONDAY,TUESDAY,WEDNESDAY,THURSDAY,FRIDAY,SATURDAY,SUNDAY; val value: Int get() = ordinal + 1 companion object { private val ENUMS = DayOfWeek.values() fun of(dayOfWeek: Int): DayOfWeek { if (dayOfWeek < 1 || dayOfWeek > 7) { throw RuntimeException("Invalid value for DayOfWeek: " + dayOfWeek) } return ENUMS[dayOfWeek - 1] } } }

我的TypeConverter：

@H_403_6@private const val SEPARATOR = "," class DayOfWeekConverter { @TypeConverter fun daysOfWeekToString(daysOfWeek: List<DayOfWeek>?): String? { return daysOfWeek?.map { it.value }?.joinToString(separator = SEPARATOR) } @TypeConverter fun stringToDaysOfWeek(daysOfWeek: String?): List<DayOfWeek>? { return daysOfWeek?.split(SEPARATOR)?.map { DayOfWeek.of(it.toInt()) } } }

我将它设置在我的DB类中,如下所示：

@H_403_6@@Database(entities = arrayOf(Example::class),version = 1) @TypeConverters(DayOfWeekConverter::class) abstract class AppDatabase : RoomDatabase() { abstract fun exampleDao(): ExampleDao }

我的DAO看起来像这样：

@H_403_6@@Dao interface ExampleDao { @Query("SELECT * FROM example") fun getAll(): LiveData<List<Example>> @Insert(onConflict = REPLACE) fun save(examples: List<Example>) }

我用这段代码得到的错误是：

@H_403_6@error: Cannot figure out how to save this field into database. You can consider adding a type converter for it. e: e: private java.util.List<? extends com.example.DayOfWeek> days;

就像我上面说的,如果我将days属性更改为ArrayList< DayOfWeek> (并在DayOfWeekConverter中对ArrayList进行更改)然后一切正常.如果有人能帮我解决这个问题并告诉我如何在这里使用List它会有很大的帮助,它让我发疯：/.