Hilt ViewModel constructor not working when navigation component scope

Question

It is my first time when I am playing around with Hilt. I have created a demo app with BottomNavigationView. I have added @AndroidEntryPoint and @HiltAndroidApp. I created a Module class and injected the ViewModel but I am still getting the same error over and over again.

Class <ViewModel> has no zero argument constructor

Some code:

@HiltAndroidApp
class MyApplication: Application() {
}

<application
    android:name=".MyApplication"

@AndroidEntryPoint
class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val navView: BottomNavigationView = findViewById(R.id.nav_view)

        val navController = findNavController(R.id.nav_host_fragment)
        navView.setupWithNavController(navController)
    }
}

@AndroidEntryPoint
class CampaignsFragment : Fragment() {

    private var _binding: FragmentCampaignsBinding? = null
    private val binding get() = _binding!!

    private val campaignsViewModel: CampaignsViewModel by navGraphViewModels(R.id.mobile_navigation) {
        defaultViewModelProviderFactory
    }

    override fun onCreateView(
            inflater: LayoutInflater,
            container: ViewGroup?,
            savedInstanceState: Bundle?
    ): View? {
        _binding = FragmentCampaignsBinding.inflate(inflater, container, false)
        return binding.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        campaignsViewModel.getCampaigns()
    }

    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }
}

class CampaignsViewModel @ViewModelInject constructor(
    private val db: FirebaseFirestore,
    @Assisted private val savedStateHandle: SavedStateHandle
): ViewModel() {

    fun getCampaigns() {
        db.collection("campaigns")
            .get()
            .addOnSuccessListener {
                for (document in it) {
                    Log.d(BuildConfig.BUILD_TYPE, "${document.id} => ${document.data}")
                }
            }
            .addOnFailureListener {

            }
    }
}

@Module
@InstallIn(FragmentComponent::class)
class ApplicationModule {

    @Provides
    fun provideFirebaseFirestore(): FirebaseFirestore {
        return Firebase.firestore
    }
}

I have added all the code I am using. Am I missing something? I couldn't find any example or missing errors. I did read the hilt documentation about ViewModel and the implementation.

app gradle file content:

plugins {
    id 'com.android.application'
    id 'kotlin-android'
    id 'com.google.gms.google-services'
    id 'kotlin-android-extensions'
    id 'kotlin-kapt'
    id 'dagger.hilt.android.plugin'
}

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.2"

    defaultConfig {
        applicationId "ro.marianpavel.partidulverde"
        minSdkVersion 21
        targetSdkVersion 30
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    buildFeatures {
        viewBinding true
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
}

dependencies {

    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    implementation 'androidx.core:core-ktx:1.3.2'
    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'com.google.android.material:material:1.2.1'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.2'
    implementation 'androidx.navigation:navigation-fragment-ktx:2.3.1'
    implementation 'androidx.navigation:navigation-ui-ktx:2.3.1'
    implementation 'androidx.lifecycle:lifecycle-livedata-ktx:2.2.0'
    implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.2.0'
    implementation 'androidx.navigation:navigation-fragment-ktx:2.3.1'
    implementation 'androidx.navigation:navigation-ui-ktx:2.3.1'
    implementation platform('com.google.firebase:firebase-bom:25.12.0')
    implementation 'com.google.firebase:firebase-analytics-ktx'
    implementation 'com.google.firebase:firebase-firestore-ktx'
    testImplementation 'junit:junit:4.13.1'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'

    implementation "com.google.dagger:hilt-android:2.29-alpha"
    implementation 'androidx.hilt:hilt-lifecycle-viewmodel:1.0.0-alpha02'
    kapt "com.google.dagger:hilt-android-compiler:2.29-alpha"
}

Answer 1

I think this might have something to do with the way you provide your firebase dependency. With FragmentComponent::class your ViewModel can't access this dependency. This should work when changing it with ApplicationComponent::class.

Another problem could be that you are missing kapt "com.google.dagger:hilt-android-compiler:$dagger_hilt_version" as well as kapt "androidx.hilt:hilt-compiler:$dagger_hilt_lc_version" in your gradle