Tus*_*rma 6 android kotlin data-access-object android-room android-architecture-components
我是 Android 开发新手,我正在尝试通过遵循 Android 架构组件来制作一个笔记应用程序,但在运行时,我在 DAO 中遇到错误,如果有人可以提供帮助,我将不胜感激。这是我收到的代码和错误。
道:-
'''
@Dao
interface NoteDao {
@Insert(onConflict = OnConflictStrategy.IGNORE)
suspend fun insert(note :Note)
@Delete
suspend fun delete(note : Note)
@Query("SELECT * FROM Notes_table order by id")
fun getALL(): LiveData<List<Note>>
@Query("SELECT * From Notes_table where id= :pos")
fun getSpecific(pos :Int):Note
}
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'''
实体:-
'''
@Entity(tableName = "Notes_table")
data class Note(@ColumnInfo(name="noteText") val text:String) {
@PrimaryKey(autoGenerate = true) var id:Int =0
}
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''' 数据库:-
'''
@Database(entities = [Note::class],version = 1,exportSchema = false)
abstract class NoteDatabase : RoomDatabase() {
abstract fun getNoteDao():NoteDao
companion object{
@Volatile
private var Instance: NoteDatabase?=null
fun getDatabase(context :Context):NoteDatabase{
return Instance ?: synchronized(this){
val instance=Room.databaseBuilder(context.applicationContext,
NoteDatabase::class.java,"note_database").build()
Instance=instance
instance
}
}
}
}
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DAO 的进口:-
import androidx.lifecycle.LiveData
import androidx.room.
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实体进口:-
import androidx.room.ColumnInfo
import androidx.room.Entity
import androidx.room.PrimaryKey
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数据库导入:-
import android.content.Context
import androidx.room.Database
import androidx.room.Room
import androidx.room.RoomDatabase
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如果需要,我可以提供其余的代码。
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