Room: Receiving error when using @Transaction

问题

I'm have a method annotated with @Transaction in my DAO class, which is causing the following error:

A DAO method can be annotated with only one of the following:Insert,Delete,Query,Update

Here's my class:

@Dao interface Dao {

    @Insert(onConflict = REPLACE) fun insertList(chacaras: List<String>)

    @Query("SELECT * FROM chacara WHERE cityId = :cityId")
    fun getListOfCity(cityId: String): LiveData<List<String>>

    @Delete fun deleteList(chacaraList: List<String>)

    @Transaction
    fun updateList(list: List<String>){
        deleteList(list)
        insertList(list)
    }

}

When I remove the method annotated with @Transaction it compiles normally. Is there anyway to fix this?

回答1:

According to the transaction documentation

Marks a method in an abstract Dao class as a transaction method.

Change your class to:

@Dao abstract class Dao {

    @Insert(onConflict = REPLACE) abstract fun insertList(chacaras: List<String>)

    @Query("SELECT * FROM chacara WHERE cityId = :cityId")
    abstract fun getListOfCity(cityId: String): LiveData<List<String>>

    @Delete abstract fun deleteList(chacaraList: List<String>)

    @Transaction
    open fun updateList(list: List<String>){
        deleteList(list)
        insertList(list)
    }

}

来源：https://stackoverflow.com/questions/46730172/room-receiving-error-when-using-transaction