How to use data-binding with Fragment

Question

I m trying to follow data-binding example from official google doc https   developer android com tools data-binding guide html  except that I m trying to apply data-biding to a fragment  not an activity   the error I m currently getting when compiling is   Error  37  27  No resource type specified  at  text  with value    marsdata martianSols    onCreate for fragment looks like this    Override public void onCreate  Nullable Bundle savedInstanceState        super onCreate savedInstanceState       MartianDataBinding binding   MartianDataBinding inflate getActivity   getLayoutInflater         binding setMarsdata this       onCreateView for fragment looks like this    Nullable  Override public View onCreateView LayoutInflater inflater   Nullable ViewGroup container   Nullable Bundle savedInstanceState        return inflater inflate R layout martian data  container  false       and parts of my layout file for fragment looks like this    lt  xml version  1 0  encoding  utf-8   gt    lt layout xmlns android  http   schemas android com apk res android  gt       lt data gt           lt variable             name  marsdata              type  uk co darkruby app myapp MarsDataProvider    gt       lt  data gt                lt TextView             android layout height  wrap content              android layout width  wrap content              android text    marsdata martianSols             gt        lt  RelativeLayout gt   lt  layout gt    my suspicion is that MartianDataBinding doesn t know which layout file it s supposed to be bound with - hence the error  Any suggestions

User · Answer

A complete example in data binding Fragments

FragmentMyProgramsBinding is binding class generated for res/layout/fragment_my_programs

public class MyPrograms extends Fragment {
    FragmentMyProgramsBinding fragmentMyProgramsBinding;

    public MyPrograms() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
    FragmentMyProgramsBinding    fragmentMyProgramsBinding = DataBindingUtil.inflate(inflater, R
                .layout.fragment_my_programs, container, false);
        return fragmentMyProgramsBinding.getRoot();
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

    }
}

User · Answer

Very helpful blog about Databinding   https   link medium com HQY2VizKO1  class FragmentBinding lt out T   ViewDataBinding gt        LayoutRes private val resId  Int     ReadOnlyProperty lt Fragment  T gt         private var binding  T    null      override operator fun getValue          thisRef  Fragment          property  KProperty lt   gt         T   binding    createBinding thisRef  also   binding   it        private fun createBinding          activity  Fragment        T   DataBindingUtil inflate LayoutInflater from activity context  resId null true      Declare binding val like this in Fragment    private val binding by FragmentBinding lt FragmentLoginBinding gt  R layout fragment login    Don t forget to write this in fragment   override fun onCreateView      inflater  LayoutInflater      container  ViewGroup       savedInstanceState  Bundle     View        return binding root

User · Answer

Try this in Android DataBinding  FragmentMainBinding binding    Override public View onCreateView LayoutInflater inflater  ViewGroup container                               Bundle savedInstanceState            binding   DataBindingUtil inflate inflater  R layout fragment main  container  false           View rootView   binding getRoot            initInstances savedInstanceState           return rootView

User · Answer

One can simply retrieve view object as mentioned below  public View onCreateView LayoutInflater inflater   Nullable ViewGroup container   Nullable Bundle savedInstanceState     View view   DataBindingUtil inflate inflater  R layout layout file  container  false  getRoot     return view

User · Answer

Another example in Kotlin   override fun onCreateView inflater  LayoutInflater   container  ViewGroup   savedInstanceState  Bundle    View        val binding   DataBindingUtil              inflate lt  MartianDataBinding  gt                       inflater                      R layout bla                      container                      false                    binding modelName              return binding root     Note that the name  MartianDataBinding  depends on the name of the layout file  If the file is named  martian data  then the correct name would be MartianDataBinding

User · Answer

Kotlin syntax   lateinit var binding  MartianDataBinding override fun onCreateView inflater  LayoutInflater   container  ViewGroup   savedInstanceState  Bundle    View        binding   DataBindingUtil inflate inflater  R layout martian data  container  false      return binding root

User · Answer

The data binding implementation must be in the onCreateView method of the fragment  delete any data Binding that exist in your OnCreate method  your onCreateView should look like this   public View onCreateView LayoutInflater inflater                             Nullable ViewGroup container                             Nullable Bundle savedInstanceState        MartianDataBinding binding   DataBindingUtil inflate              inflater  R layout martian data  container  false       View view   binding getRoot          here data must be an instance of the class MarsDataProvider     binding setMarsdata data       return view

User · Answer

You are actually encouraged to use the inflate method of your generated Binding and not the DataBindingUtil    Override public View onCreateView LayoutInflater inflater  ViewGroup container  Bundle savedInstanceState        MainFragmentBinding binding   MainFragmentBinding inflate inflater  container  false         set variables in Binding     return binding getRoot        Docs for DataBindingUtil inflate        Use this version only if layoutId is unknown in advance  Otherwise  use the generated Binding s inflate method to ensure type-safe inflation

User · Answer

Even the other answers may work well  but I want tell best approach  Use Binding class s inflate as recommended in Android Documentation  One option is to inflate by DataBindingUtil but when only you don t know have generated binding class  --You have auto generated binding class  use that class instead of using DataBindingUtil  In Java  Override public View onCreateView LayoutInflater inflater  ViewGroup container  Bundle savedInstanceState        HomeFragmentBinding binding   HomeFragmentBinding inflate inflater  container  false         set binding variables here     return binding getRoot       In Kotlin lateinit var binding  HomeFragmentBinding  override fun onCreateView inflater  LayoutInflater   container  ViewGroup   savedInstanceState  Bundle    View        binding   HomeFragmentBinding inflate inflater  container  false      return binding root    In DataBindingUtil class documentation you can see   inflate T inflate  LayoutInflater inflater                   int layoutId                   ViewGroup parent                   boolean attachToParent   Use this version only if layoutId is unknown in advance  Otherwise  use the generated Binding s inflate method to ensure type-safe inflation   If your layout biniding class is not generated  See this answer

User · Answer

If you are using ViewModel and LiveData This is the sufficient syntax  Kotlin Syntax   override fun onCreateView      inflater  LayoutInflater      container  ViewGroup       savedInstanceState  Bundle     View        return MartianDataBinding inflate          inflater          container          false       apply           lifecycleOwner   viewLifecycleOwner         vm   viewModel       Attach your view model here       root

User · Answer

Everyone says about inflate    but what if we want to use it in onViewCreated     You can use bind view  method of concrete binding class to get ViewDataBinding instance for the view     Usually we write BaseFragment something like this  simplified       BaseFragment kt abstract fun layoutId    Int  override fun onCreateView inflater  container  savedInstanceState         inflater inflate layoutId    container  false    And use it in child fragment      ConcreteFragment kt override fun layoutId     R layout fragment concrete  override fun onViewCreated view  savedInstanceState        val binding   FragmentConcreteBinding bind view         or     val binding   DataBindingUtil bind lt FragmentConcreteBinding gt  view        If all Fragments uses data binding  you can even make it simpler using type parameter   abstract class BaseFragment lt B  ViewDataBinding gt    Fragment         abstract fun onViewCreated binding  B  savedInstanceState  Bundle        override fun onViewCreated view  View  savedInstanceState  Bundle             onViewCreated DataBindingUtil bind lt B gt  view     savedInstanceState            I don t know it s okay to assert non-null there  but   you get the idea  If you want it to be nullable  you can do it

User · Answer

Just as most have said  but dont forget to set LifeCycleOwner  Sample in Java i e  public View onCreateView LayoutInflater inflater  ViewGroup container Bundle savedInstanceState        super onCreateView inflater  container  savedInstanceState       BindingClass binding   DataBindingUtil inflate inflater  R layout fragment layout  container  false       ModelClass model   ViewModelProviders of getActivity    get ViewModelClass class       binding setLifecycleOwner getActivity         binding setViewmodelclass model          Your codes here      return binding getRoot

User · Answer

working in my code   private FragmentSampleBinding dataBiding  private SampleListAdapter mAdapter    Nullable  Override public View onCreateView LayoutInflater inflater   Nullable ViewGroup container   Nullable Bundle savedInstanceState        super onCreateView inflater  container  savedInstanceState       dataBiding   DataBindingUtil inflate inflater  R layout fragment sample  null  false       return mView   dataBiding getRoot

User · Answer

I have been finding Answer for my application and here is the answer for Kotlin Language    private lateinit var binding  FragmentForgetPasswordBinding  override fun onCreateView          inflater  LayoutInflater  container  ViewGroup           savedInstanceState  Bundle         View    binding DataBindingUtil inflate inflater R layout fragment forget password container false          val viewModel ViewModelProvider this  get ForgetPasswordViewModel  class java          binding recoveryViewModel viewModel         viewModel forgetPasswordInterface this         return binding root

[android] How to use data-binding with Fragment

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