Activity/Fragment Kotlin Extension for initialising ViewModel with Factory/Arguments constructor

ViewModelExtension

inline fun <reified T : ViewModel> Fragment.getActivityViewModel(noinline creator: (() -> T)? = null): T {
    return if (creator == null)
        ViewModelProviders.of(activity!!).get(T::class.java)
    else
        ViewModelProviders.of(activity!!, BaseViewModelFactory(creator)).get(T::class.java)
}

inline fun <reified T : ViewModel> Fragment.getViewModel(noinline creator: (() -> T)? = null): T {
    return if (creator == null)
        ViewModelProviders.of(this).get(T::class.java)
    else
        ViewModelProviders.of(this, BaseViewModelFactory(creator)).get(T::class.java)
}

inline fun <reified T : ViewModel> FragmentActivity.getViewModel(noinline creator: (() -> T)? = null): T {
    return if (creator == null)
        ViewModelProviders.of(this).get(T::class.java)
    else
        ViewModelProviders.of(this, BaseViewModelFactory(creator)).get(T::class.java)
}

/////////////////////
class BaseViewModelFactory<T>(val creator: () -> T) : ViewModelProvider.Factory {
    override fun <T : ViewModel?> create(modelClass: Class<T>): T {
        return creator() as T
    }
}

//////////////////// HOW TO USE ////////////////
// In acitivity/Fragment

private val viewModel: MyViewModel by lazy {
        getActivityViewModel {
            MyViewModel(arg1, arg2, arg3)
        }
    }