BaseFragment1.kt

abstract class BaseFragment<B : ViewDataBinding, VM : BaseViewModel>(@LayoutRes private val layoutResourceId: Int) : Fragment() {

    private var realBinding: B? = null
    protected val binding: B get() = realBinding ?: throw IllegalStateException("Trying to access the binding outside of the view lifecycle.")
    protected abstract val viewModel: VM

    final override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? =
        DataBindingUtil.inflate<B>(inflater, layoutResourceId, container, false).also {
            realBinding = it
        }.root

    @CallSuper
    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        binding.lifecycleOwner = viewLifecycleOwner
        binding.setVariable(BR.viewModel, viewModel)
    }

    override fun onDestroyView() {
        super.onDestroyView()
        realBinding = null
    }
}