Kotlin generic in BaseClass. Trying to get ViewModel by generic type in BaseFragment

Issue

Hey I want to create BaseFragment class that gets viewModel by generic type:

abstract class BaseFragment<B : ViewDataBinding, VM : ViewModel> : DaggerFragment() {

    val viewModel by viewModels<VM> { viewModelFactory }
    ...
}

// Native function
@MainThread
inline fun <reified VM : ViewModel> Fragment.viewModels(
    noinline ownerProducer: () -> ViewModelStoreOwner = { this },
    noinline factoryProducer: (() -> Factory)? = null
) = createViewModelLazy(VM::class, { ownerProducer().viewModelStore }, factoryProducer)

but getting error Cannot use 'VM' as reified type parameter. Use a class instead.

is it at all possible to achieve what I am trying to do? Maybe with other approach?

Solution

There is clearer solution:

abstract class BaseActivity<VM : BaseViewModel> : AppCompatActivity {

    protected val viewModel: VM by viewModel(clazz = getViewModelClass())

    private fun getViewModelClass(): KClass<VM> = (
    (javaClass.genericSuperclass as ParameterizedType)
        .actualTypeArguments[0] as Class<VM>
    ).kotlin
}

And usage:

class MainActivity : BaseActivity<MainViewModel>(R.layout.activity_main) {

    override fun onCreate(savedInstanceState: Bundle?) {
       super.onCreate(savedInstanceState)
       viewModel.onViewCreated()
    }
}

Answered By - ianbelow