Is there way to inject viewmodels without having t...

# dagger

[blakelee]

Is there way to inject viewmodels without having to create a factory for each one and also without hilt? I don’t need savedStateHandle or anything, I just want to use it like @Inject but have it survive configuration changes that a normal class won’t survive.

I’ve seen several medium articles but I haven’t found a solution that can do it without a factory or hilt

[allan.conda]

@Binds
@IntoMap @ViewModelClassKey(LoginViewModel::class)
abstract fun bindViewModel(viewModel: SomeViewModel): ViewModel

[allan.conda]

look for tutorials involving ViewModelClassKey

[Ahmed Ibrahim]

Yes, there is, since you don't use SavedStateHandle you can do it by using a Provider.

@Inject
lateinit var viewModelProvider: Provider<MyViewModel>

private val myViewModel by viewModels {
    viewModelProvider.get()
}

[blakelee]

@allan.conda That just replaces the factory with a binds

@Ahmed Ibrahim The viewModelProvider.get() doesn't seem to work. viewModels wants a ViewModelProvider.Factory

[allan.conda]

Yeah… you said no Factory or Hilt… That’s the plain Dagger solution

[blakelee]

I was hoping there was a way to set it up with just @Inject like many of my other classes. I thought there was a way to do it similar to what Ahmed was suggesting, but I must be mistaken.

[allan.conda]

using Hilt is the closest to what you’re looking for with @ViewModelInject
otherwise there’s no easy way since ViewModels are a corner case,

[Ahmed Ibrahim]

@blakelee Hey, sorry for providing an incomplete code, but yeah it's missing the ViewModelProvider.Factory as you said, but you can get around that by doing

@Inject
    lateinit var viewModelProvider: Provider<MyViewModel>

    private val myViewModel: MyViewModel by viewModels {
        object: ViewModelProvider.Factory {
            override fun <T : ViewModel> create(modelClass: Class<T>): T {
                @Suppress("UNCHECKED_CAST")
                return viewModelProvider.get() as T
            }
        }
    }

Now you can replace the ugly object: ViewModelProvider.Factory part by extracting it to an inline function to get a much more elegant version of the above code

@Inject
    lateinit var viewModelProvider: Provider<ViewModel>

    private val myViewModel: ViewModel by viewModels {
       createSimpleViewModelFactory {        viewModelProvider.get() 
}
    }

[blakelee]

@Ahmed Ibrahim This seems like it could work. It's running on my device just fine. Just gotta make sure it really does handle config changes. Thanks!