Question

在构建使用Room库，使用Dagger进行依赖项注入和Kotlin的项目时，遇到此错误：

[kapt]发生异常：java.lang.IllegalArgumentException：无法将void转换为Element

这是我的代码：

`{
        implementation ...        
        implementation 'com.google.firebase:firebase-core:15.0.2'
        implementation 'com.google.firebase:firebase-messaging:15.0.2'
    }`

以下是我如何使用DAO的示例：

@Entity(tableName = "contacts_table")
data class Contact(@PrimaryKey var cid: Long,
          @ColumnInfo(name = "firstColor") var firstColor: String?,
          @ColumnInfo(name = "secondColor") var secondColor: String?,
          @ColumnInfo(name = "avatarUrl") var avatarUrl: String?,
          @ColumnInfo(name = "name") var name: String,
          @ColumnInfo(name = "nickname") var nickname: String)


@Dao
interface ContactsDao {

     @Insert(onConflict = REPLACE)
     fun insertContact(contact: Contact)

     @Query("delete from contacts_table where cid=:id")
     fun deleteContactById(id: Long)

     @Query("select * from contacts_table")
     fun getAllContacts() : List<Contact>
}


@Database(entities = [Contact::class], version = 1, exportSchema = false)
abstract class AppDatabase : RoomDatabase() {
     abstract fun contactsDao()
}

如何解决此构建错误？

Answer 1

您必须在AppDatabase中为contactsDao()指定一个返回类型。它必须是ContactsDao。因此，您的课程应如下所示：

@Database(entities = [Contact::class], version = 1, exportSchema = false)
abstract class AppDatabase : RoomDatabase() {
     abstract fun contactsDao(): ContactsDao
}

使用Room构建时发生错误：kap发生异常：java.lang.IllegalArgumentException：无法将void转换为Element

1 个答案: