android - 房间 : Receiving error when using @Transaction

Question

我的 DAO 类中有一个用 @Transaction 注释的方法，这会导致以下错误:

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

这是我的课:

@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)
    }

}

当我删除带有@Transaction 注释的方法时，它会正常编译。有没有办法解决这个问题？

Answer 1

根据transaction documentation

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

将您的类(class)更改为:

@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)
    }

}