Question

我有一个下面的界面，用于创建标准的crud方法，并使用插入，更新和删除方法对方法进行注释。

interface BaseDao<T> {
    @Insert
    fun insert(table: T): Single<Long>

    @Insert
    fun insert(vararg table: T): Single<List<Long>>

    @Update
    fun update(table: T): Single<Int>

    @Delete
    fun delete(table: T): Single<Int>
}

然后我为DAO创建一个接口

@Dao
interface WeatherDao : BaseDao<WeatherTable> {

    override fun insert(table: WeatherTable): Single<Long>

    override fun insert(vararg table: WeatherTable): Single<List<Long>>

    override fun update(table: WeatherTable): Single<Int>

    override fun delete(table: WeatherTable): Single<Int>

    @Query("SELECT * FROM weatherTable")
    fun getAllWeather(): Single<List<WeatherTable>>

    @Query("SELECT * FROM weatherTable WHERE id = :id LIMIT 1")
    fun getWeatherById(id: Long): Single<WeatherTable>

    @Query("SELECT count(*) FROM weatherTable")
    fun count(): Single<Int>
}

当我编译时，会出现很多如下错误：

error: An abstract DAO method must be annotated with one and only one of the following annotations: Insert,Delete,Query,Update,RawQuery
    public abstract io.reactivex.Single<java.lang.Long> delete(@org.jetbrains.annotations.NotNull()

因为当我从接口继承时。我必须手动添加@ Insert，@ Update和@Delete。

只是想知道为什么这些注释会自动添加到我的WeatherDao界面中。

所以我现在必须像这样手动添加它们：

@Dao
interface WeatherDao : BaseDao<WeatherTable> {

    @Insert
    override fun insert(table: WeatherTable): Single<Long>

    @Insert
    override fun insert(vararg table: WeatherTable): Single<List<Long>>

    @Update
    override fun update(table: WeatherTable): Single<Int>

    @Delete
    override fun delete(table: WeatherTable): Single<Int>

    @Query("SELECT * FROM weatherTable")
    fun getAllWeather(): Single<List<WeatherTable>>

    @Query("SELECT * FROM weatherTable WHERE id = :id LIMIT 1")
    fun getWeatherById(id: Long): Single<WeatherTable>

    @Query("SELECT count(*) FROM weatherTable")
    fun count(): Single<Int>
}

只是想知道我是否使用了这个错误：

Answer 1

遵循此google repo之后，您没有正确进行抽象。综上所述，您无需在@Dao接口中插入/更新/删除操作，它应该是抽象的。

interface BaseDao<T> {

    /**
     * Insert an object in the database.
     *
     * @param obj the object to be inserted.
     */
    @Insert
    fun insert(obj: T)

    /**
     * Insert an array of objects in the database.
     *
     * @param obj the objects to be inserted.
     */
    @Insert
    fun insert(vararg obj: T)

    /**
     * Update an object from the database.
     *
     * @param obj the object to be updated
     */
    @Update
    fun update(obj: T)

    /**
     * Delete an object from the database
     *
     * @param obj the object to be deleted
     */
    @Delete
    fun delete(obj: T)
}

@Entity(tableName = "data")
data class Data(@PrimaryKey val id: String, val value: String)

@Dao
abstract class DataDao : BaseDao<Data>() {

    /**
     * Get all data from the Data table.
     */
    @Query("SELECT * FROM Data")
    abstract fun getData(): List<Data>
}

从会议室DAO界面继承

1 个答案: