Dagger在ModelView中注入上下文

Question

I'm trying to inject the Context in my ModelView but I'm a little bit confused:

Here is my Module , I send him an Application for later use the context from this, but I don't know where it comes from this Application or how to take it:

@Module
class module {
    @Provides @Singleton fun appContext(application: Application): Context{
        return application
    }
}

And here is my Component :

@Component(modules = [module::class])
interface component {
    fun providesApplication(): Application
}

To finish I don't know how to inject this in my ViewModel because this don't have constructor to inject it.

How should I inject the context to my ViewModel ?

Answer 1

There is already build-in ViewModel with context, replace inheritance from ViewModel with AndroidViewModel

See: https://developer.android.com/reference/android/arch/lifecycle/AndroidViewModel

Answer 2

alternatively, you could try something like this :

class YourViewModel @Inject constructor(context:Context) : ViewModel()

Merely a suggestion if nothing else works, hear me out...

var context: Context? = null

fun initViewModelWithContext(context: Context) {
    this.context = context
}

you could potentially do something like this as well, if you don't find a solution with dagger. all your functions can then use this local instance of context, and this ViewModel will be destroyed/created as it is needed so it won't be causing any memory issues