Android/Room/ViewModel：将 ViewModel 保存到房间数据库时出错

Question

I have an activity which uses a ViewModel class to store and manage UI-related data. The view model class used in the activity has a structure similar to the one given below:

class SomeViewModel:ViewModel(){
  @PrimaryKey(autoGenerate=true)
  var id=0

  var field1:Array<Double?>=arrayOf(null,null)
  var field2:Array<Double?>=arrayOf(null,null)
  var field3:Array<Double?>=arrayOf(null,null)

  @Ignore
  val someFragments=HashMap<String,Fragment>()
  @Ignore
  val someMap=HashMap<String,Int>()
}

What I am trying to do is to save the data in the view model object to the local database when back is pressed to close the activity. But the issue is when I am trying to do so I am getting an error.

Cannot figure out how to save this field into database. You can consider adding a type converter for it. - mBagOfTags in androidx.lifecycle.ViewModelerror: Cannot find getter for field. - mBagOfTags in androidx.lifecycle.ViewModelerror: Cannot find getter for field. - mCleared in androidx.lifecycle

I am using a TypeConverter identical to the one given below:

class Converter{
    @TypeConverter
    fun fromArrayDouble(field:Array<Double?>):String{
        val s=StringBuilder("")
        var first=true
        for(k in field){
            s.append(k.toString())
            if(first){
                s.append(",")
                first=false
            }
        }
        return s.toString()
    }

    @TypeConverter
    fun fromString(str:String):Array<Double?>{
        val parts=str.split(',')
        val res=ArrayList<Double?>()
        for(p in parts){
            try{
                res.add(p.toDouble())
            }catch(e:Exception){
                res.add(null)
            }
        }
        return res.toTypedArray()
    }
}

and a database class similar to:

@Database(entities=[SomeViewModel::class], version=1, exportSchema=false)
@TypeConverters(Converter:class)
abstract class SomeDatabase:RoomDatabase(){
  // database definition
}

I don't understand where I am going wrong. Any help will be highly appreciated.

Answer 1

Please refer to this answer from another post.

Kotlin room does not allow defining variables in entity class start of 'i' character. I had the same error. I solved it, albeit difficult. Replace id with pId and it will be fine.

Or probably you need to add getter to be found by Room.

fun getId(): Int {
    return id
}