How to pass my viewmodel to a class that does not extend activity - android-jetpack

Question

How to pass my viewmodel to a class that does not extend activity
I'm calling my viewmodel like this:
in my EntryAbstract class
where am I going wrong
val FrutasViewModel = ViewModelProvider.NewInstanceFactory().create(FrutasViewModel::class.java)
FrutasViewModel.frutaData.value.forEach { item->
itens.add(ShoppingCart
(id=item.id,photo=item.photo,
name=item.name,quantidade=item.quantidade
,categoria = item.categoria,descricao = item.descricao
,unidade=item.unidade,kilo = item.kilo
))
}
my viewmodel:
package com.example.quitanda.models
import android.util.Log
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.launch
class FrutasViewModel(
private val frutasServices: Services,
):ViewModel() {
private val _frutasData: MutableStateFlow<List<ShoppingCart>> = MutableStateFlow<List<ShoppingCart>>(listOf<ShoppingCart>(ShoppingCart()))
val frutaData: StateFlow<List<ShoppingCart>>
get() = _frutasData
fun getFrutas(){
viewModelScope.launch {
try {
val frutas = frutasServices.getFruta()
_frutasData.value = frutas
}catch (e:Exception){
Log.d("Service error",e.toString())
}
}
}
}
My service:
package com.example.quitanda.models
import retrofit2.Retrofit
import retrofit2.converter.moshi.MoshiConverterFactory
import retrofit2.http.GET
interface Services {
#GET("/category/7")
suspend fun getFruta(
//#Query("apikey")
//apikey:String = "333b4285"
): List<ShoppingCart>
}
val retrofit: Retrofit = Retrofit.Builder()
.baseUrl("http://localhost:4000/")
.addConverterFactory(MoshiConverterFactory.create())
.build()
val frutasServices: Services = retrofit.create(Services::class.java)
My model:
package com.example.quitanda.models
import android.os.Parcelable
import com.squareup.moshi.Json
import kotlinx.parcelize.Parcelize
#Parcelize
data class ShoppingCart(
var count:Int=0,
#field:Json(name="product_title")
var name:String="",
#field:Json(name="product_id")
var id:Int=0,
#field:Json(name="photo_photo")
var photo:String="",
#field:Json(name="product_quant")
var quantidade:Int=0,
#field:Json(name="category_name")
var categoria:String="",
#field:Json(name="product_description")
var descricao:String="",
#field:Json(name="product_price_un")
var unidade:String="",
#field:Json(name="product_price_kg")
var kilo:String="",
var tipos:String=""): Parcelable
When I try to run my code it gives the following error
Does anyone have any idea how to fix this
who can help I am grateful
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.quitanda, PID: 11031
java.lang.RuntimeException: Cannot create an instance of class com.example.quitanda.models.FrutasViewModel

Answer 1

I wouldn't recommend doing what you're trying to achieve, because what Android did, is that they've abstracted how viewmodels are scoped, to give you developers the power to easily handle things like orientation-change.
In practice this means, that android views, such as Activity/Fragment implement a ViewModelStoreOwner which contains a ViewModelStore, which handles the scoping and retrieves the correct ViewModel instance based on context.
TL;DR: If you want an android arch.viewmodel then create it in your Activity/Fragment and pass it to the EntryAbstract, though chances are you just need some of the data, which could be set individually for better separation of concerns