[英]Application dependency to ViewModel with HILT
我想知道如何使用 Hilt 将应用程序依赖项传递给 ViewModel? 我正在尝试使用 AndroidViewModel,但我做不到。 有人能帮我吗? 一些简短的样本对我来说可能意义重大。
这是我的视图模型:
class MainViewModel @ViewModelInject constructor(
private val application: Application,
private val repository: Repository,
@Assisted private val savedStateHandle: SavedStateHandle
) : ViewModel() {
这是我的刀柄模块
@Module
@InstallIn(ApplicationComponent::class)
object DatabaseModule {
@Singleton
@Provides
fun provideDatabase(
@ApplicationContext context: Context
) = Room.databaseBuilder(
context,
MyDatabase::class.java,
"my_database"
).build()
@Singleton
@Provides
fun provideDao(database: MyDatabase) = database.myDao()
@Singleton
@Provides
fun provideRepository(myDao: MyDao) = Repository(myDao)
@Singleton
@Provides
fun provideApplicationContext() = MyApplication()
}
其他一切都很好,我收到了错误消息:
引起:java.lang.RuntimeException:无法创建类 com.example.example.viewmodel.MainViewModel 的实例引起:java.lang.InstantiationException:java.lang.Class<com.example.example.viewmodel.MainViewModel> 有无零参数构造函数
你可以看到完整的源代码https://github.com/Kotlin-Android-Open-Source/MVI-Coroutines-Flow/tree/dagger_hilt
@Singleton
class UserRepositoryImpl @Inject constructor(
private val userApiService: UserApiService,
private val dispatchers: CoroutineDispatchers,
...
) : UserRepository { ... }
class AddUserUseCase @Inject constructor(private val userRepository: UserRepository) {
suspend operator fun invoke(user: User) = userRepository.add(user)
}
class RemoveUserUseCase @Inject constructor(private val userRepository: UserRepository) {
suspend operator fun invoke(user: User) = userRepository.remove(user)
}
class RefreshGetUsersUseCase @Inject constructor(private val userRepository: UserRepository) {
suspend operator fun invoke() = userRepository.refresh()
}
...
class MainVM @ViewModelInject constructor(
private val getUsersUseCase: GetUsersUseCase,
private val refreshGetUsers: RefreshGetUsersUseCase,
private val removeUser: RemoveUserUseCase,
) : ViewModel() { ... }
@AndroidEntryPoint
class MainActivity : AppCompatActivity(), View {
private val mainVM by viewModels<MainVM>()
...
}
注入应用程序上下文:
Hilt
已经提供了应用上下文: @Singleton
@Provides
fun provideApplicationContext() = MyApplication()
class MainViewModel @ViewModelInject constructor(
@ApplicationContext private val context: Context,
private val repository: Repository,
@Assisted private val savedStateHandle: SavedStateHandle
) : ViewModel() {
在构造函数中使用@ApplicationContext Context context
作为参数。
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