不確定如何在 Room Android 中將 Cursor 轉換為該方法的返回類型？

Question

構建應用程序時出現以下錯誤

Not sure how to convert a Cursor to this method's return type (kotlinx.coroutines.flow.Flow<? extends java.util.List<com.notification.NotificationEntity>>)

這是我的實體類

@Entity
internal data class NotificationEntity(
@PrimaryKey @ColumnInfo(name = "notification_id") val notificationId: String,
val title: String,
val body: String?,
@ColumnInfo(name = "is_actionable") val isActionable: Boolean,
@ColumnInfo(name = "created_at") val createdAt: Instant,
@ColumnInfo(name = "is_read") val isRead: Boolean = false)

這是我的道課

@Dao
internal interface NotificationDao {

@Query("SELECT * FROM NotificationEntity ORDER BY created_at ASC")
suspend fun getAllNotifications(): Flow<List<NotificationEntity>>

@Insert(onConflict = OnConflictStrategy.REPLACE)
suspend fun saveNotification(notifications: List<NotificationEntity>)
}

有人可以幫助這里有什么問題嗎？

Answer 1

當您聲明返回Flow的 Dao 函數時，該函數不應是可掛起的。 請參閱文檔。

將您的代碼更改為：

@Dao
internal interface NotificationDao {

@Query("SELECT * FROM NotificationEntity ORDER BY created_at ASC")
fun getAllNotifications(): Flow<List<NotificationEntity>>

@Insert(onConflict = OnConflictStrategy.REPLACE)
suspend fun saveNotification(notifications: List<NotificationEntity>)
}

如果尚未添加，則為 NotificationEntity 中使用的Instant類型添加類型轉換器。