android - 如何在 Room Db 上使用挂起功能？

Question

我在 kotlin 中使用协程使用 Room Db。这是我的道界面:

@Dao
interface CheckListNameDao {

    @Insert
    suspend fun insertName(name: CheckListName)


    @Query("SELECT * FROM CheckListNamesTable")
    fun getAllNames(): LiveData<List<CheckListName>>
}

getAllNames()方法工作正常。问题在于 insertName()方法。当我删除 suspend来自 insertName() 的关键字方法，它会抛出这个异常: java.lang.IllegalStateException: Cannot access database on the main thread since it may potentially lock the UI for a long period of time.但是，当我使用 suspend关键字，我不能再构建项目了。它显示以下错误:

error: Methods annotated with @Insert can return either void, long, Long, long[], Long[] or List<Long>.
public abstract java.lang.Object insertName(@org.jetbrains.annotations.NotNull()

为什么显示此错误？我的代码是基于这个 Android Room with a View - Kotlin

编辑:
这是我的存储库:

class MainRepository(application: Application) {

        private var nameDao: CheckListNameDao = AppDatabase.getDatabase(application.applicationContext)
                .checkListNameDao()

        fun getAllNames(): LiveData<List<CheckListName>> {
            return nameDao.getAllNames()
        }

        suspend fun setNewListName(checkListName: CheckListName) {
            nameDao.insertName(checkListName)
        }
    }

这是 View 模型:

class MainViewModel(application: Application) : AndroidViewModel(application) {

    private var mainRepository = MainRepository(application)

    fun getAllNames(): LiveData<List<CheckListName>> {
        return mainRepository.getAllNames()
    }

    fun setNewListName(name: String) {
        viewModelScope.launch {
            mainRepository.setNewListName(CheckListName(0, name))
        }
    }
}

编辑 2:

添加 suspend 时也出现此错误关键词:

error: Type of the parameter must be a class annotated with @Entity or a collection/array of it.
kotlin.coroutines.Continuation<? super kotlin.Unit> p1);

这是 CheckListName数据类:

@Entity(tableName = "CheckListNamesTable")
data class CheckListName(

        @PrimaryKey(autoGenerate = true)
        var id: Int,

        var name: String
)

Answer 1

根据 Room Declaring Dependencies documentation , 你需要依赖 room-ktx使用协程，并使用它，suspend方法:

implementation "androidx.room:room-ktx:2.2.3"