add assisted inject (#15)

* add assisted inject

* add backing field for arguments

* add assisted inject + run spotlessApplly

* move initialization to init for consistency with the MainViewModel
fix test

* change to trailing lambda

* revert unused change

* remove unused import

Author: yehezkiell

app/build.gradle

@@ -35,6 +35,11 @@ android {
                 arguments += ["room.schemaLocation" : "$projectDir/schemas".toString()]
             }
         }
+        javaCompileOptions {
+            annotationProcessorOptions {
+                arguments["dagger.hilt.disableModulesHaveInstallInCheck"] = "true"
+            }
+        }
     }
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_8
@@ -103,6 +108,8 @@ dependencies {
     implementation "com.google.dagger:hilt-android:$versions.daggerHiltCoreVersion"
     implementation "androidx.hilt:hilt-common:$versions.daggerHiltVersion"
     implementation "androidx.hilt:hilt-lifecycle-viewmodel:$versions.daggerHiltVersion"
+    compileOnly "com.squareup.inject:assisted-inject-annotations-dagger2:$versions.assistedInjectVersion"
+    kapt "com.squareup.inject:assisted-inject-processor-dagger2:$versions.assistedInjectVersion"
     kapt "com.google.dagger:hilt-compiler:$versions.daggerHiltCoreVersion"
     kapt "androidx.hilt:hilt-compiler:$versions.daggerHiltVersion"
     androidTestImplementation "com.google.dagger:hilt-android-testing:$versions.daggerHiltCoreVersion"

app/src/main/java/com/skydoves/pokedex/di/AssistedInjectModule.kt

@@ -0,0 +1,32 @@
+/*
+ * Designed and developed by 2020 skydoves (Jaewoong Eum)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.skydoves.pokedex.di
+
+import com.squareup.inject.assisted.dagger2.AssistedModule
+import dagger.Module
+import dagger.hilt.InstallIn
+import dagger.hilt.android.components.ActivityRetainedComponent
+
+// AssistedInject puts all assisted bindings in the same module.
+// We need to make a decision about where to install it.
+// In this case, as we only need it in activity, we install it there.
+// source: https://gist.github.com/manuelvicnt/437668cda3a891d347e134b1de29aee1
+@InstallIn(ActivityRetainedComponent::class)
+@AssistedModule
+@Module(includes = [AssistedInject_AssistedInjectModule::class])
+// Needed until AssistedInject is incorporated into Dagger
+interface AssistedInjectModule

app/src/main/java/com/skydoves/pokedex/ui/details/DetailActivity.kt

@@ -29,21 +29,34 @@ import com.skydoves.pokedex.model.Pokemon
 import com.skydoves.transformationlayout.TransformationCompat
 import com.skydoves.transformationlayout.TransformationLayout
 import dagger.hilt.android.AndroidEntryPoint
+import javax.inject.Inject
 
 @AndroidEntryPoint
 class DetailActivity : DataBindingActivity() {
 
-  @VisibleForTesting val viewModel: DetailViewModel by viewModels()
+  @Inject
+  lateinit var detailViewModelFactory: DetailViewModel.AssistedFactory
+
+  @VisibleForTesting
+  val viewModel: DetailViewModel by viewModels {
+    DetailViewModel.provideFactory(
+      detailViewModelFactory,
+      pokemonItem.name
+    )
+  }
+
   private val binding: ActivityDetailBinding by binding(R.layout.activity_detail)
 
+  private val pokemonItem: Pokemon
+    get() = requireNotNull(intent.getParcelableExtra(EXTRA_POKEMON))
+
   override fun onCreate(savedInstanceState: Bundle?) {
     onTransformationEndContainerApplyParams()
     super.onCreate(savedInstanceState)
-    val pokemonItem: Pokemon = requireNotNull(intent.getParcelableExtra(EXTRA_POKEMON))
     binding.apply {
       pokemon = pokemonItem
       lifecycleOwner = this@DetailActivity
-      vm = viewModel.apply { fetchPokemonInfo(pokemonItem.name) }
+      vm = viewModel
     }
   }
 

app/src/main/java/com/skydoves/pokedex/ui/details/DetailViewModel.kt

@@ -16,45 +16,56 @@
 
 package com.skydoves.pokedex.ui.details
 
-import androidx.annotation.MainThread
 import androidx.databinding.ObservableBoolean
-import androidx.hilt.lifecycle.ViewModelInject
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.asLiveData
-import androidx.lifecycle.switchMap
 import com.skydoves.pokedex.base.LiveCoroutinesViewModel
 import com.skydoves.pokedex.model.PokemonInfo
 import com.skydoves.pokedex.repository.DetailRepository
+import com.squareup.inject.assisted.Assisted
+import com.squareup.inject.assisted.AssistedInject
 import timber.log.Timber
 
-class DetailViewModel @ViewModelInject constructor(
-  private val detailRepository: DetailRepository
+class DetailViewModel @AssistedInject constructor(
+  private val detailRepository: DetailRepository,
+  @Assisted private val pokemonName: String
 ) : LiveCoroutinesViewModel() {
 
-  private var pokemonFetchingLiveData: MutableLiveData<String> = MutableLiveData()
-  val pokemonInfoLiveData: LiveData<PokemonInfo?>
-
   val isLoading: ObservableBoolean = ObservableBoolean(false)
   val toastLiveData: MutableLiveData<String> = MutableLiveData()
+  val pokemonInfoLiveData: LiveData<PokemonInfo?>
 
   init {
     Timber.d("init DetailViewModel")
-
-    pokemonInfoLiveData = pokemonFetchingLiveData.switchMap {
-      isLoading.set(true)
-      launchOnViewModelScope {
-        this.detailRepository.fetchPokemonInfo(
-          name = it,
+    pokemonInfoLiveData = launchOnViewModelScope(
+      block = {
+        isLoading.set(true)
+        detailRepository.fetchPokemonInfo(
+          name = pokemonName,
           onSuccess = { isLoading.set(false) },
           onError = { toastLiveData.postValue(it) }
         ).asLiveData()
       }
-    }
+    )
   }
 
-  @MainThread
-  fun fetchPokemonInfo(name: String) {
-    pokemonFetchingLiveData.value = name
+  @AssistedInject.Factory
+  interface AssistedFactory {
+    fun create(pokemonName: String): DetailViewModel
+  }
+
+  companion object {
+    fun provideFactory(
+      assistedFactory: AssistedFactory,
+      pokemonName: String
+    ): ViewModelProvider.Factory = object : ViewModelProvider.Factory {
+      @Suppress("UNCHECKED_CAST")
+      override fun <T : ViewModel?> create(modelClass: Class<T>): T {
+        return assistedFactory.create(pokemonName) as T
+      }
+    }
   }
 }

app/src/test/java/com/skydoves/pokedex/viewmodel/DetailViewModelTest.kt

@@ -33,7 +33,6 @@ import com.skydoves.pokedex.repository.DetailRepository
 import com.skydoves.pokedex.ui.details.DetailViewModel
 import com.skydoves.pokedex.utils.MockUtil
 import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.delay
 import kotlinx.coroutines.runBlocking
 import org.junit.Before
 import org.junit.Rule
@@ -59,7 +58,7 @@ class DetailViewModelTest {
   @Before
   fun setup() {
     detailRepository = DetailRepository(pokdexClient, pokemonInfoDao)
-    viewModel = DetailViewModel(detailRepository)
+    viewModel = DetailViewModel(detailRepository, "skydoves")
   }
 
   @Test
@@ -76,9 +75,6 @@ class DetailViewModelTest {
       ).asLiveData()
     fetchedData.observeForever(observer)
 
-    viewModel.fetchPokemonInfo(name = "skydoves")
-    delay(500L)
-
     verify(pokemonInfoDao, atLeastOnce()).getPokemonInfo(name_ = "skydoves")
     verify(observer).onChanged(mockData)
     fetchedData.removeObserver(observer)

dependencies.gradle

@@ -43,6 +43,7 @@ ext.versions = [
     // di
     daggerHiltCoreVersion: '2.29.1-alpha',
     daggerHiltVersion    : '1.0.0-alpha02',
+    assistedInjectVersion: '0.5.2',
 
     // network
     retrofitVersion      : '2.9.0',