hi guys! i'm trying to migrate from Koin to Hilt what is the best way to inject fields into the Base...

# dagger

[deviant]

hi guys!
i'm trying to migrate from Koin to Hilt
what is the best way to inject fields into the BaseViewModel?
i have such structure: MyViewModel extends BaseViewModel extends ViewModel
is it possible to inject directly into the fields/properties of BaseViewModel?

[Arun]

Newly released Hilt is the recommended way for ViewModel injections.

Guides are here https://developer.android.com/training/dependency-injection/hilt-jetpack

[deviant]

thanks. i saw it. so the only way to inject is via constructor?

[Arun]

I would say that is the best practice. Member injection is possible but not recommended since it will cause tight coupling between Component and ViewModel.

@Inject and @Assisted on constructor is a good way to start

[deviant]

abstract class BaseViewModel() : ViewModel() {
    @Inject
    protected lateinit var prefs: Prefs

this doesn't work for me. and @ViewModelInject can't be applied on properties 😞
i don't care about tight coupling in current project. what i'm trying to do is leave base class constructor as clean as possible

[Arun]

You can avoid @Inject in the base classes and just use @Inject in the deriving classes. A guide to this is here https://proandroiddev.com/clean-dagger-f248eda5790b

Basically:

abstract class BaseViewModel(val prefs: Prefs) : ViewModel

and subclass

class HomeViewModel @Inject constructor(override val prefs: Prefs) : ViewModel()

[deviant]

that's almost how i managed it eventually. i made the property abstract and override it in the child object constructor. thanks mate!

[gildor]

Yes, it’s recommended approach with dagger, inject only top most class, do not inject abstract classes

[Colton Idle]

@gildor I didn't know this. Thanks! Do you know if there's a reference to that claim? I would like to attach it to my PR where I'm going to remove @Inject ions into some base classes.