viewmodel expect/actual

app/build.gradle.kts

@@ -48,6 +48,8 @@ android {
 dependencies {
     implementation(project(":shared"))
     implementation(libs.bundles.app.ui)
+    implementation(libs.multiplatformSettings.common)
+    implementation(libs.kotlinx.dateTime)
     coreLibraryDesugaring(libs.android.desugaring)
     implementation(libs.koin.android)
     testImplementation(libs.junit)

app/src/main/java/co/touchlab/kampkit/android/MainActivity.kt

@@ -6,6 +6,7 @@ import androidx.activity.compose.setContent
 import co.touchlab.kampkit.android.ui.MainScreen
 import co.touchlab.kampkit.android.ui.theme.KaMPKitTheme
 import co.touchlab.kampkit.injectLogger
+import co.touchlab.kampkit.models.BreedViewModel
 import co.touchlab.kermit.Logger
 import org.koin.androidx.viewmodel.ext.android.viewModel
 import org.koin.core.component.KoinComponent
@@ -22,8 +23,5 @@ class MainActivity : ComponentActivity(), KoinComponent {
                 MainScreen(viewModel, log)
             }
         }
-        if (viewModel.breedStateFlow.value.data == null) {
-            viewModel.refreshBreeds()
-        }
     }
 }

app/src/main/java/co/touchlab/kampkit/android/MainApp.kt

@@ -6,7 +6,9 @@ import android.content.SharedPreferences
 import android.util.Log
 import co.touchlab.kampkit.AppInfo
 import co.touchlab.kampkit.initKoin
+import co.touchlab.kampkit.models.BreedViewModel
 import org.koin.androidx.viewmodel.dsl.viewModel
+import org.koin.core.parameter.parametersOf
 import org.koin.dsl.module
 
 class MainApp : Application() {
@@ -16,7 +18,7 @@ class MainApp : Application() {
         initKoin(
             module {
                 single<Context> { this@MainApp }
-                viewModel { BreedViewModel() }
+                viewModel { BreedViewModel(get(), get { parametersOf("BreedViewModel") }) }
                 single<SharedPreferences> {
                     get<Context>().getSharedPreferences("KAMPSTARTER_SETTINGS", Context.MODE_PRIVATE)
                 }

app/src/main/java/co/touchlab/kampkit/android/ui/Composables.kt

@@ -32,9 +32,9 @@ import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.flowWithLifecycle
-import co.touchlab.kampkit.android.BreedViewModel
 import co.touchlab.kampkit.android.R
 import co.touchlab.kampkit.db.Breed
+import co.touchlab.kampkit.models.BreedViewModel
 import co.touchlab.kampkit.models.DataState
 import co.touchlab.kampkit.models.ItemDataSummary
 import co.touchlab.kermit.Logger
@@ -47,16 +47,16 @@ fun MainScreen(
     log: Logger
 ) {
     val lifecycleOwner = LocalLifecycleOwner.current
-    val lifecycleAwareDogsFlow = remember(viewModel.breedStateFlow, lifecycleOwner) {
-        viewModel.breedStateFlow.flowWithLifecycle(lifecycleOwner.lifecycle)
+    val lifecycleAwareDogsFlow = remember(viewModel.breeds, lifecycleOwner) {
+        viewModel.breeds.flowWithLifecycle(lifecycleOwner.lifecycle)
     }
 
     @SuppressLint("StateFlowValueCalledInComposition") // False positive lint check when used inside collectAsState()
-    val dogsState by lifecycleAwareDogsFlow.collectAsState(viewModel.breedStateFlow.value)
+    val dogsState by lifecycleAwareDogsFlow.collectAsState(viewModel.breeds.value)
 
     MainScreenContent(
         dogsState = dogsState,
-        onRefresh = { viewModel.refreshBreeds(true) },
+        onRefresh = { viewModel.refreshBreeds() },
         onSuccess = { data -> log.v { "View updating with ${data.allItems.size} breeds" } },
         onError = { exception -> log.e { "Displaying error: $exception" } },
         onFavorite = { viewModel.updateBreedFavorite(it) }

ios/KaMPKitiOS.xcodeproj/project.pbxproj

@@ -8,6 +8,7 @@
 
 /* Begin PBXBuildFile section */
 		3DFF917C64A18A83DA010EE1 /* Pods_KaMPKitiOS.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = B859F3FB23133D22AB9DD835 /* Pods_KaMPKitiOS.framework */; };
+		461C74AA2788F5F3004B1FFC /* CombineAdapters.swift in Sources */ = {isa = PBXBuildFile; fileRef = 461C74A92788F5F3004B1FFC /* CombineAdapters.swift */; };
 		46A5B5EF26AF54F7002EFEAA /* BreedListScreen.swift in Sources */ = {isa = PBXBuildFile; fileRef = 46A5B5EE26AF54F7002EFEAA /* BreedListScreen.swift */; };
 		46A5B60826B04921002EFEAA /* Main.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 46A5B60626B04920002EFEAA /* Main.storyboard */; };
 		46B5284D249C5CF400A7725D /* Koin.swift in Sources */ = {isa = PBXBuildFile; fileRef = 46B5284C249C5CF400A7725D /* Koin.swift */; };
@@ -38,6 +39,7 @@
 /* Begin PBXFileReference section */
 		1DFCC00C8DAA719770A18D1A /* Pods-KaMPKitiOS.release.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-KaMPKitiOS.release.xcconfig"; path = "Pods/Target Support Files/Pods-KaMPKitiOS/Pods-KaMPKitiOS.release.xcconfig"; sourceTree = "<group>"; };
 		2A1ED6A4A2A53F5F75C58E5F /* Pods-KaMPKitiOS.release.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-KaMPKitiOS.release.xcconfig"; path = "Pods/Target Support Files/Pods-KaMPKitiOS/Pods-KaMPKitiOS.release.xcconfig"; sourceTree = "<group>"; };
+		461C74A92788F5F3004B1FFC /* CombineAdapters.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CombineAdapters.swift; sourceTree = "<group>"; };
 		46A5B5EE26AF54F7002EFEAA /* BreedListScreen.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BreedListScreen.swift; sourceTree = "<group>"; };
 		46A5B60726B04920002EFEAA /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/Main.storyboard; sourceTree = "<group>"; };
 		46B5284C249C5CF400A7725D /* Koin.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Koin.swift; sourceTree = "<group>"; };
@@ -134,6 +136,7 @@
 				F1465F0B23AA94BF0055F7C3 /* LaunchScreen.storyboard */,
 				F1465F0E23AA94BF0055F7C3 /* Info.plist */,
 				46A5B5EE26AF54F7002EFEAA /* BreedListScreen.swift */,
+				461C74A92788F5F3004B1FFC /* CombineAdapters.swift */,
 			);
 			path = KaMPKitiOS;
 			sourceTree = "<group>";
@@ -351,6 +354,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				46B5284D249C5CF400A7725D /* Koin.swift in Sources */,
+				461C74AA2788F5F3004B1FFC /* CombineAdapters.swift in Sources */,
 				46A5B5EF26AF54F7002EFEAA /* BreedListScreen.swift in Sources */,
 				F1465F0123AA94BF0055F7C3 /* AppDelegate.swift in Sources */,
 			);

ios/KaMPKitiOS/AppDelegate.swift

@@ -15,7 +15,6 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
     var window: UIWindow?
 
     // Lazy so it doesn't try to initialize before startKoin() is called
-    // swiftlint:disable force_cast
     lazy var log = koin.loggerWithTag(tag: "AppDelegate")
 
     func application(_ application: UIApplication, didFinishLaunchingWithOptions

ios/KaMPKitiOS/BreedListScreen.swift

@@ -6,14 +6,14 @@
 //  Copyright © 2021 Touchlab. All rights reserved.
 //
 
+import Combine
 import SwiftUI
 import shared
 
-// swiftlint:disable force_cast
 private let log = koin.loggerWithTag(tag: "ViewController")
 
 class ObservableBreedModel: ObservableObject {
-    private var viewModel: NativeViewModel?
+    private var viewModel: BreedCallbackViewModel?
 
     @Published
     var loading = false
@@ -24,8 +24,12 @@ class ObservableBreedModel: ObservableObject {
     @Published
     var error: String?
 
+    private var cancellables = [AnyCancellable]()
+
     func activate() {
-        viewModel = NativeViewModel { [weak self] dataState in
+        let viewModel = KotlinDependencies.shared.getBreedViewModel()
+
+        doPublish(viewModel.breeds) { [weak self] dataState in
             self?.loading = dataState.loading
             self?.breeds = dataState.data?.allItems
             self?.error = dataState.exception
@@ -36,11 +40,16 @@ class ObservableBreedModel: ObservableObject {
             if let errorMessage = dataState.exception {
                 log.e(message: {"Displaying error: \(errorMessage)"})
             }
-        }
+        }.store(in: &cancellables)
+
+        self.viewModel = viewModel
     }
 
     func deactivate() {
-        viewModel?.onDestroy()
+        cancellables.forEach { $0.cancel() }
+        cancellables.removeAll()
+
+        viewModel?.clear()
         viewModel = nil
     }
 
@@ -49,7 +58,7 @@ class ObservableBreedModel: ObservableObject {
     }
 
     func refresh() {
-        viewModel?.refreshBreeds(forced: true)
+        viewModel?.refreshBreeds()
     }
 }
 

ios/KaMPKitiOS/CombineAdapters.swift

@@ -0,0 +1,40 @@
+import Combine
+import shared
+
+/// Create a Combine publisher from the supplied `FlowAdapter`. Use this in contexts where more transformation will be
+/// done on the Swift side before the value is bound to UI
+func createPublisher<T>(_ flowAdapter: FlowAdapter<T>) -> AnyPublisher<T, KotlinError> {
+    return Deferred<Publishers.HandleEvents<PassthroughSubject<T, KotlinError>>> {
+        let subject = PassthroughSubject<T, KotlinError>()
+        let canceller = flowAdapter.subscribe(
+            onEach: { item in subject.send(item) },
+            onComplete: { subject.send(completion: .finished) },
+            onThrow: { error in subject.send(completion: .failure(KotlinError(error))) }
+        )
+        return subject.handleEvents(receiveCancel: { canceller.cancel() })
+    }.eraseToAnyPublisher()
+}
+
+/// Prepare the supplied `FlowAdapter` to be bound to UI. The `onEach` callback will be called from `DispatchQueue.main`
+/// on every new emission.
+///
+/// Note that this calls `assertNoFailure()` internally so you should handle errors upstream to avoid crashes.
+func doPublish<T>(_ flowAdapter: FlowAdapter<T>, onEach: @escaping (T) -> Void) -> Cancellable {
+    return createPublisher(flowAdapter)
+        .assertNoFailure()
+        .compactMap { $0 }
+        .receive(on: DispatchQueue.main)
+        .sink { onEach($0) }
+}
+
+/// Wraps a `KotlinThrowable` in a `LocalizedError` which can be used as  a Combine error type
+class KotlinError: LocalizedError {
+    let throwable: KotlinThrowable
+
+    init(_ throwable: KotlinThrowable) {
+        self.throwable = throwable
+    }
+    var errorDescription: String? {
+        throwable.message
+    }
+}

shared/build.gradle.kts

@@ -75,6 +75,7 @@ kotlin {
         }
         val androidMain by getting {
             dependencies {
+                implementation(libs.androidx.lifecycle.viewmodel)
                 implementation(libs.sqlDelight.android)
                 implementation(libs.ktor.client.okHttp)
             }

shared/src/androidMain/kotlin/co/touchlab/kampkit/models/ViewModel.kt

@@ -0,0 +1,13 @@
+package co.touchlab.kampkit.models
+
+import kotlinx.coroutines.CoroutineScope
+import androidx.lifecycle.ViewModel as AndroidXViewModel
+import androidx.lifecycle.viewModelScope as androidXViewModelScope
+
+actual abstract class ViewModel actual constructor() : AndroidXViewModel() {
+    actual val viewModelScope: CoroutineScope = androidXViewModelScope
+
+    actual override fun onCleared() {
+        super.onCleared()
+    }
+}

shared/src/commonMain/kotlin/co/touchlab/kampkit/Koin.kt

@@ -2,6 +2,7 @@ package co.touchlab.kampkit
 
 import co.touchlab.kampkit.ktor.DogApi
 import co.touchlab.kampkit.ktor.DogApiImpl
+import co.touchlab.kampkit.models.BreedRepository
 import co.touchlab.kermit.Logger
 import co.touchlab.kermit.StaticConfig
 import co.touchlab.kermit.platformLogWriter
@@ -63,6 +64,16 @@ private val coreModule = module {
     // See https://github.com/touchlab/Kermit
     val baseLogger = Logger(config = StaticConfig(logWriterList = listOf(platformLogWriter())), "KampKit")
     factory { (tag: String?) -> if (tag != null) baseLogger.withTag(tag) else baseLogger }
+
+    single {
+        BreedRepository(
+            get(),
+            get(),
+            get(),
+            getWith("BreedRepository"),
+            get()
+        )
+    }
 }
 
 internal inline fun <reified T> Scope.getWith(vararg params: Any?): T {

shared/src/commonMain/kotlin/co/touchlab/kampkit/models/BreedModel.kt → shared/src/commonMain/kotlin/co/touchlab/kampkit/models/BreedRepository.kt

@@ -2,7 +2,6 @@ package co.touchlab.kampkit.models
 
 import co.touchlab.kampkit.DatabaseHelper
 import co.touchlab.kampkit.db.Breed
-import co.touchlab.kampkit.injectLogger
 import co.touchlab.kampkit.ktor.DogApi
 import co.touchlab.kermit.Logger
 import co.touchlab.stately.ensureNeverFrozen
@@ -11,15 +10,16 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.mapNotNull
 import kotlinx.datetime.Clock
-import org.koin.core.component.KoinComponent
-import org.koin.core.component.inject
 
-class BreedModel : KoinComponent {
-    private val dbHelper: DatabaseHelper by inject()
-    private val settings: Settings by inject()
-    private val dogApi: DogApi by inject()
-    private val log: Logger by injectLogger("BreedModel")
-    private val clock: Clock by inject()
+class BreedRepository(
+    private val dbHelper: DatabaseHelper,
+    private val settings: Settings,
+    private val dogApi: DogApi,
+    log: Logger,
+    private val clock: Clock
+) {
+
+    private val log = log.withTag("BreedModel")
 
     companion object {
         internal const val DB_TIMESTAMP_KEY = "DbTimestampKey"