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I'm trying to implement data-binding in android with kotlin:

override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        mBinding = DataBindingUtil.inflate<ViewDataBinding>(
            inflater, R.layout.fragment_login, container, false
        ) as FragmentLoginBinding
        val view: View = mBinding.root
        mBinding.login?.invoke(viewModel)
        return view
But it says lateinit property viewModel has not been initialized on runtime. How can I resolve this ?
Initializing in fragment will work
It will better if you guys provide me with viewmodel initialized from parent, parent is an activity
If You want to init viewModel in Activity and use it in fragment You can do it in this way:
MainActvity.kt:
private lateinit var viewModel: MainActivityVM
override fun onCreate(savedInstanceState: Bundle?)
    viewModel = ViewModelProvider(this).get(MainActivityVM::class.java)
    super.onCreate(savedInstanceState)
YourFragment.kt:
private lateinit var binding: YourFragmentBinding
private lateinit var viewModel: MainActivityVM
override fun onCreateView(
    inflater: LayoutInflater, container: ViewGroup?,
    savedInstanceState: Bundle?
): View?
    binding = DataBindingUtil.inflate(
        inflater,
        R.layout.fragment_your, container, false
    binding.lifecycleOwner = this
    viewModel = ViewModelProvider(requireActivity()).get(MainActivityVM::class.java)
    //here You can use Your viewModel
    return binding.root
lateinit properties require you to initialize them before the first use. The error happens only if it wasn't initialized. You can check if lateinit is initialized by using isInitialized property of KProperty0 interface.
val isReadyForUse = ::viewModel.isInitialized
Inside of a Fragment you can initialize a ViewModel using extension function viewModels():
import androidx.fragment.app.viewModels
class YourFragment: Fragment {
    private val viewModel: YourViewModel by viewModels()
It's lazy-loaded, which means as soon as you'll try to access viewModel it will be initialized and returned. Next time no initialization will happen.
If you want to make your ViewModel class loaded in an Activity first and later in a Fragment use activityViewModels().
Note: after the first initialization of a ViewModel by activityViewModels() it will be stored in a ViewModelStore that is owned by Activity. To create new instance of a YourViewModel by using activityViewModels() you will have to finish your Activity or clear view model store requireActivity().viewModelStore.clear().
To initialize in an Activity and use a Fragment do next:
class YourActivity {
    override fun onCreate(savedInstanceState: Bundle?) {
        val viewModelInit = ViewModelProvider(this).get(YourViewModel.javaClass)
And in a Fragment:
import androidx.fragment.app.activityViewModels
class YourFragment: Fragment {
    private val viewModel: YourViewModel by activityViewModels()
Here is the thing worked for me :
mBinding = DataBindingUtil.inflate<ViewDataBinding>(
            inflater, R.layout.fragment_login, container, false
        ) as FragmentLoginBinding
        val view: View = mBinding.root
        viewModel = ViewModelProvider(requireActivity()).get(AuthViewModel::class.java)
        mBinding.login = viewModel
        return view
In XML :
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">
        <variable
            name="login"
            type="com........." />
    </data>
        
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