Getting a null object exception with ViewBinding while everyhting works fine when using FindViewById - android-fragments

Question

Within my fragment code, i was trying to attach on click listener to this button so i can use it to navigate through a navigation graph.
When using viewbinding the app crashes with a null object exception, using find view by id fixes the problem,
I wanna know what's wrong !
java.lang.NullPointerException: Attempt to read from field 'android.widget.TextView com.example.teleport.databinding.FragmentLoginBinding.registerLink' on a null object reference
that's the error i get and here's the fragment code
public class LoginFragment extends Fragment implements View.OnClickListener {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private FragmentLoginBinding binding;
private NavController navController;
private TextView registerLink;
public LoginFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* #param param1 Parameter 1.
* #param param2 Parameter 2.
* #return A new instance of fragment LoginFragment.
*/
// TODO: Rename and change types and number of parameters
public static LoginFragment newInstance(String param1, String param2) {
LoginFragment fragment = new LoginFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_login, container, false);
}
#Override
public void onViewCreated(#NonNull #NotNull View view, #Nullable #org.jetbrains.annotations.Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
navController = Navigation.findNavController(view);
//registerLink = (TextView) view.findViewById(R.id.register_link);
//registerLink.setOnClickListener(this);
registerLink = (TextView) binding.registerLink;
registerLink.setOnClickListener(this);
}
#Override
public void onClick(View v) {
switch (v.getId()){
case R.id.register_link:
navController.navigate(R.id.nav_register);
break;
}
}
}

Answer 1

You need to create a binding instance in the onCreateView() method.
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// create instance of binding here
binding = FragmentLoginBinding.inflate(inflater, container, false);
return binding.getRoot();
}
Also, explicitly you do not need to get the reference of the views, like
registerLink = (TextView) binding.registerLink;
registerLink.setOnClickListener(this);
You can just directly us the binding instance as
binding.registerLink.setOnClickListener(this);
For more details, check the documentation here.