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androiddependency-injectionandroid-viewmodeldagger-hilt
UmAnusorn
UmAnusorn

Reputation: 11124

Android Hilt dagger inject interface in viewModel @ViewModelInject got UninitializedPropertyAccessException

I trying on Hilt codelab https://codelabs.developers.google.com/codelabs/android-hilt#10

It's working fine with Activity and Fragment

logger is a RoomDB

Then I try to inject logger into viewModel with this article

By add

implementation "androidx.hilt:hilt-lifecycle-viewmodel
    :1.0.0-alpha02"
kapt 'androidx.hilt:hilt-compiler:1.0.0-alpha02'

ViewModelCode

class RecordFragmentViewModel @ViewModelInject constructor(@Assisted private val savedStateHandle: SavedStateHandle) :
    ViewModel() {
    @DatabaseLogger
    @Inject
    lateinit var logger: LoggerDataSource

Class logger to inject

 class LoggerLocalDataSource 
@Inject constructor(private val logDao: LogDao) : LoggerDataSource {

LoggingModule

@Qualifier
annotation class InMemoryLogger

@Qualifier
annotation class DatabaseLogger

@InstallIn(ApplicationComponent::class)
@Module
abstract class LoggingDatabaseModule {

    @DatabaseLogger
    @Singleton
    @Binds
    abstract fun bindDatabaseLogger(impl: LoggerLocalDataSource): LoggerDataSource
}

@InstallIn(ActivityComponent::class)
@Module
abstract class LoggingInMemoryModule {

    @InMemoryLogger
    @ActivityScoped
    @Binds
    abstract fun bindInMemoryLogger(impl: LoggerInMemoryDataSource): LoggerDataSource
}

DatabaseModule

@InstallIn(ApplicationComponent::class)
@Module
object DatabaseModule {

    @Provides
    @Singleton
    fun provideDatabase(@ApplicationContext appContext: Context): AppDatabase {
        return Room.databaseBuilder(
            appContext,
            AppDatabase::class.java,
            "logging.db"
        ).build()
    }

    @Provides
    fun provideLogDao(database: AppDatabase): LogDao {
        return database.logDao()
    }
}

It's compile and run without error. However, I use debug to watch logger and its got.

Method threw 'kotlin.UninitializedPropertyAccessException' exception.

I call logger.something() at run time its throw

Fatal Exception: kotlin.UninitializedPropertyAccessException
lateinit property logger has not been initialized

More info https://dagger.dev/hilt/migration-guide.html

https://codelabs.developers.google.com/codelabs/android-hilt#10

https://medium.com/mobile-app-development-publication/injecting-viewmodel-with-dagger-hilt-54ca2e433865

Upvotes: 6

Views: 9540

Answers (1)

UmAnusorn
UmAnusorn

Reputation: 11124

Since LoggerDataSource is a interface we need to specify which implementation we need to inject. Thanks to @Andrew for the idea of inject to constructor

class RecordFragmentViewModel
@ViewModelInject
constructor(@Assisted private val savedStateHandle: SavedStateHandle,
            @DatabaseLogger private val logger: LoggerDataSource) :
    ViewModel(), LifecycleObserver {

To specify

@Qualifier
annotation class InMemoryLogger

@Qualifier
annotation class DatabaseLogger

@InstallIn(ApplicationComponent::class)
@Module
abstract class LoggingDatabaseModule {

    @DatabaseLogger
    @Singleton
    @Binds
    abstract fun bindDatabaseLogger(impl: LoggerLocalDataSource): LoggerDataSource
}

@InstallIn(ActivityComponent::class)
@Module
abstract class LoggingInMemoryModule {

    @InMemoryLogger
    @ActivityScoped
    @Binds
    abstract fun bindInMemoryLogger(impl: LoggerInMemoryDataSource): LoggerDataSource
}

Upvotes: 4

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