Use Fruitties ViewModel on iOS

Fruitties/androidApp/src/main/java/com/example/fruitties/android/ui/ListScreen.kt

@@ -57,7 +57,7 @@ import androidx.lifecycle.viewmodel.MutableCreationExtras
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.example.fruitties.android.R
 import com.example.fruitties.android.di.App
-import com.example.fruitties.database.CartItemDetails
+import com.example.fruitties.model.CartItemDetails
 import com.example.fruitties.model.Fruittie
 import com.example.fruitties.viewmodel.MainViewModel
 
@@ -79,7 +79,7 @@ fun ListScreen() {
         extras = extras,
     )
 
-    val uiState by viewModel.uiState.collectAsState()
+    val uiState by viewModel.homeUiState.collectAsState()
     val cartState by viewModel.cartUiState.collectAsState()
 
     Scaffold(
@@ -108,7 +108,7 @@ fun ListScreen() {
             var expanded by remember { mutableStateOf(false) }
             Row(modifier = Modifier.padding(16.dp)) {
                 Text(
-                    text = "Cart has ${cartState.itemList.count()} items",
+                    text = "Item types in cart: ${cartState.cartDetails.count()}",
                     modifier = Modifier.weight(1f).padding(12.dp),
                 )
                 Button(onClick = { expanded = !expanded }) {
@@ -120,11 +120,11 @@ fun ListScreen() {
                 enter = fadeIn(animationSpec = tween(1000)),
                 exit = fadeOut(animationSpec = tween(1000)),
             ) {
-                CartDetailsView(cartState.itemList)
+                CartDetailsView(cartState.cartDetails)
             }
 
             LazyColumn {
-                items(items = uiState.itemList, key = { it.id }) { item ->
+                items(items = uiState.fruitties, key = { it.id }) { item ->
                     FruittieItem(
                         item = item,
                         onAddToCart = viewModel::addItemToCart,

Fruitties/iosApp/iosApp/CartView.swift

@@ -19,17 +19,17 @@ import SwiftUI
 import shared
 
 struct CartView : View {
-    let cart: Cart
-    let dataRepository: DataRepository
+    let cartDetails: [CartItemDetails]
+    let mainViewModel: MainViewModel
     @State
     private var expanded = false
 
     var body: some View {
-        if (cart.items.isEmpty) {
+        if (cartDetails.isEmpty) {
             Text("Cart is empty, add some items").padding()
         } else {
             HStack {
-                Text("Cart has \(cart.items.count) items").padding()
+                Text("Item types in cart: \(cartDetails.count)").padding()
                 Spacer()
                 Button {
                     expanded.toggle()
@@ -42,22 +42,22 @@ struct CartView : View {
                 }.padding()
             }
             if (expanded) {
-                CartDetailsView(dataRepository: dataRepository)
+                CartDetailsView(mainViewModel: mainViewModel)
             }
         }
     }
 }
 
 struct CartDetailsView: View {
-    let dataRepository: DataRepository
+    let mainViewModel: MainViewModel
     @State
-    private var details: CartDetails = CartDetails(items: [])
+    private var cartUiState: CartUiState = CartUiState(cartDetails: [])
 
     var body: some View {
         VStack {
-            ForEach(details.items, id: \.fruittie.id) { item in
+            ForEach(cartUiState.cartDetails, id: \.fruittie.id) { item in
                 Text("\(item.fruittie.name): \(item.count)")
             }
-        }.collectWithLifecycle(dataRepository.cartDetails, binding: $details)
+        }.collectWithLifecycle(mainViewModel.cartUiState, binding: $cartUiState)
     }
 }

Fruitties/iosApp/iosApp/ContentView.swift

@@ -20,13 +20,13 @@ import Foundation
 
 struct ContentView: View {
     @ObservedObject var uiModel: UIModel
-    init(appContainer: AppContainer) {
-        self.uiModel = UIModel(dataRepository: appContainer.dataRepository)
+    init(mainViewModel: MainViewModel) {
+        self.uiModel = UIModel(mainViewModel: mainViewModel)
     }
 
     var body: some View {
         Text("Fruitties").font(.largeTitle).fontWeight(.bold)
-        CartView(cart: uiModel.cart, dataRepository: uiModel.dataRepository)
+        CartView(cartDetails: uiModel.cartDetails, mainViewModel: uiModel.mainViewModel)
         ScrollView {
             LazyVStack {
                 ForEach(uiModel.fruitties, id: \.self) { value in
@@ -67,37 +67,37 @@ struct FruittieView: View {
 }
 
 class UIModel: ObservableObject {
-    let dataRepository : DataRepository
-    init(dataRepository: DataRepository) {
-        self.dataRepository = dataRepository
+    let mainViewModel: MainViewModel
+    init(mainViewModel: MainViewModel) {
+        self.mainViewModel = mainViewModel
     }
     @Published
     private(set) var fruitties: [Fruittie] = []
     @Published
-    private(set) var cart: Cart = Cart(items: [])
+    private(set) var cartDetails: [CartItemDetails] = []
 
     @MainActor
-    func observeDatabase() async {
-        for await fruitties in dataRepository.getData() {
-            self.fruitties = fruitties
+    func observeHomeUiState() async {
+        for await homeUiState in mainViewModel.homeUiState {
+            self.fruitties = homeUiState.fruitties
         }
     }
 
     @MainActor
-    func watchCart() async {
-        for await cart in dataRepository.getCart() {
-            self.cart = cart
+    func observeCartUiState() async {
+        for await cartUiState in mainViewModel.cartUiState {
+            self.cartDetails = cartUiState.cartDetails
         }
     }
 
     func addToCart(fruittie: Fruittie) async {
-        try? await dataRepository.addToCart(fruittie: fruittie)
+        mainViewModel.addItemToCart(fruittie: fruittie)
     }
 
     @MainActor
     func activate() async {
-        async let db: () = observeDatabase()
-        async let cartUpdate: () = watchCart()
-        await (db, cartUpdate)
+        async let home: () = observeHomeUiState()
+        async let cart: () = observeCartUiState()
+        await (home, cart)
     }
 }

Fruitties/iosApp/iosApp/iOSApp.swift

@@ -21,7 +21,9 @@ struct iOSApp: App {
     let appContainer = AppContainer(factory: Factory())
     var body: some Scene {
         WindowGroup {
-            ContentView(appContainer: appContainer)
+            // TODO: Find a better owner for the ViewModelStore.
+            let iosViewModelOwner = IOSViewModelOwner(appContainer: appContainer)
+            ContentView(mainViewModel: iosViewModelOwner.mainViewModel)
         }
     }
 }

Fruitties/shared/src/commonMain/kotlin/com/example/fruitties/DataRepository.kt

@@ -16,16 +16,13 @@
 package com.example.fruitties
 
 import com.example.fruitties.database.AppDatabase
-import com.example.fruitties.database.Cart
 import com.example.fruitties.database.CartDataStore
-import com.example.fruitties.database.CartDetails
-import com.example.fruitties.database.CartItemDetails
+import com.example.fruitties.model.CartItemDetails
 import com.example.fruitties.model.Fruittie
 import com.example.fruitties.network.FruittieApi
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.count
 import kotlinx.coroutines.flow.mapLatest
 import kotlinx.coroutines.launch
 
@@ -36,27 +33,21 @@ class DataRepository(
     private val scope: CoroutineScope,
 ) {
     @OptIn(ExperimentalCoroutinesApi::class)
-    val cartDetails: Flow<CartDetails>
+    val cartDetails: Flow<List<CartItemDetails>>
         get() = cartDataStore.cart.mapLatest {
             val ids = it.items.map { it.id }
             val fruitties = database.fruittieDao().loadMapped(ids)
-            CartDetails(
-                items = it.items.mapNotNull {
-                    fruitties[it.id]?.let { fruittie ->
-                        CartItemDetails(fruittie, it.count)
-                    }
-                },
-            )
+            it.items.mapNotNull {
+                fruitties[it.id]?.let { fruittie ->
+                    CartItemDetails(fruittie, it.count)
+                }
+            }
         }
 
     suspend fun addToCart(fruittie: Fruittie) {
         cartDataStore.add(fruittie)
     }
 
-    fun getCart(): Flow<Cart> {
-        return cartDataStore.cart
-    }
-
     fun getData(): Flow<List<Fruittie>> {
         scope.launch {
             if (database.fruittieDao().count() < 1) {

Fruitties/shared/src/commonMain/kotlin/com/example/fruitties/database/CartDataStore.kt

@@ -33,19 +33,11 @@ import okio.use
 data class Cart(
     val items: List<CartItem>,
 )
-class CartDetails(
-    val items: List<CartItemDetails>,
-)
-
 @Serializable
 data class CartItem(
     val id: Long,
     val count: Int,
 )
-data class CartItemDetails(
-    val fruittie: Fruittie,
-    val count: Int,
-)
 internal object CartJsonSerializer : OkioSerializer<Cart> {
     override val defaultValue: Cart = Cart(emptyList())
     override suspend fun readFrom(source: BufferedSource): Cart {

Fruitties/shared/src/commonMain/kotlin/com/example/fruitties/di/AppContainer.kt

@@ -23,6 +23,7 @@ import kotlinx.coroutines.SupervisorJob
 class AppContainer(
     private val factory: Factory,
 ) {
+
     val dataRepository: DataRepository by lazy {
         DataRepository(
             api = factory.createApi(),

Fruitties/shared/src/commonMain/kotlin/com/example/fruitties/model/Fruittie.kt

@@ -31,3 +31,8 @@ data class Fruittie(
     @SerialName("calories")
     val calories: String,
 )
+
+data class CartItemDetails(
+    val fruittie: Fruittie,
+    val count: Int,
+)

Fruitties/shared/src/commonMain/kotlin/com/example/fruitties/viewmodel/MainViewModel.kt

@@ -23,8 +23,8 @@ import androidx.lifecycle.viewmodel.CreationExtras
 import androidx.lifecycle.viewmodel.initializer
 import androidx.lifecycle.viewmodel.viewModelFactory
 import com.example.fruitties.DataRepository
-import com.example.fruitties.database.CartItemDetails
 import com.example.fruitties.di.AppContainer
+import com.example.fruitties.model.CartItemDetails
 import com.example.fruitties.model.Fruittie
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
@@ -34,7 +34,7 @@ import kotlinx.coroutines.launch
 
 class MainViewModel(private val repository: DataRepository) : ViewModel() {
 
-    val uiState: StateFlow<HomeUiState> =
+    val homeUiState: StateFlow<HomeUiState> =
         repository.getData().map { HomeUiState(it) }
             .stateIn(
                 scope = viewModelScope,
@@ -43,7 +43,7 @@ class MainViewModel(private val repository: DataRepository) : ViewModel() {
             )
 
     val cartUiState: StateFlow<CartUiState> =
-        repository.cartDetails.map { CartUiState(it.items) }
+        repository.cartDetails.map { CartUiState(it) }
             .stateIn(
                 scope = viewModelScope,
                 started = SharingStarted.WhileSubscribed(TIMEOUT_MILLIS),
@@ -73,11 +73,11 @@ class MainViewModel(private val repository: DataRepository) : ViewModel() {
 /**
  * Ui State for ListScreen
  */
-data class HomeUiState(val itemList: List<Fruittie> = listOf())
+data class HomeUiState(val fruitties: List<Fruittie> = listOf())
 
 /**
  * Ui State for Cart
  */
-data class CartUiState(val itemList: List<CartItemDetails> = listOf())
+data class CartUiState(val cartDetails: List<CartItemDetails> = listOf())
 
 private const val TIMEOUT_MILLIS = 5_000L

Fruitties/shared/src/nativeMain/kotlin/com/example/fruitties/di/viewmodel/IOSViewModelOwner.kt

@@ -0,0 +1,53 @@
+package com.example.fruitties.di.viewmodel
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.ViewModelStore
+import androidx.lifecycle.ViewModelStoreOwner
+import androidx.lifecycle.viewmodel.CreationExtras
+import androidx.lifecycle.viewmodel.MutableCreationExtras
+import com.example.fruitties.di.AppContainer
+import com.example.fruitties.viewmodel.MainViewModel
+import kotlin.reflect.KClass
+
+class IOSViewModelOwner(private val appContainer: AppContainer) : ViewModelStoreOwner {
+    private var _viewModelStore: ViewModelStore? = null
+    override val viewModelStore: ViewModelStore
+        get() = _viewModelStore ?: ViewModelStore().also {
+            this._viewModelStore = it
+        }
+
+    val mainViewModel: MainViewModel = viewModel(
+        modelClass = MainViewModel::class,
+        viewModelStoreOwner = this,
+        factory = MainViewModel.Factory,
+        extras = MutableCreationExtras().apply {
+            set(MainViewModel.APP_CONTAINER_KEY, appContainer)
+        } as CreationExtras,
+    )
+
+//    TODO: Clear the ViewModelStore when going out of scope.
+//    fun clearViewModelStore() {
+//        viewModelStore.clear()
+//    }
+}
+
+private fun <VM : ViewModel> viewModel(
+    modelClass: KClass<VM>,
+    viewModelStoreOwner: ViewModelStoreOwner,
+    key: String? = null,
+    factory: ViewModelProvider.Factory? = null,
+    extras: CreationExtras = CreationExtras.Empty
+): VM {
+    val provider =
+        if (factory != null) {
+            ViewModelProvider.create(viewModelStoreOwner.viewModelStore, factory, extras)
+        } else {
+            ViewModelProvider.create(viewModelStoreOwner)
+        }
+    return if (key != null) {
+        provider[key, modelClass]
+    } else {
+        provider[modelClass]
+    }
+}