viewBinding {
            enabled = true
        }

 buildFeatures {
            viewBinding = true
        }

build//generated//data_binding_base_class_source_out//debug//out//com.你的包名//databinding

private ActivityMainBinding binding;

binding = ActivityMainBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());

binding.postMes.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startActivity(new Intent(MainActivity.this,ReceiverActivity.class));
            }
        });

  @NonNull
  public static ActivityMainBinding inflate(@NonNull LayoutInflater inflater) {
    return inflate(inflater, null, false);
  }

  @NonNull
  public static ActivityMainBinding inflate(@NonNull LayoutInflater inflater,
      @Nullable ViewGroup parent, boolean attachToParent) {
    View root = inflater.inflate(R.layout.activity_main, parent, false);
    if (attachToParent) {
      parent.addView(root);
    }
    return bind(root);
  }

@NonNull
  public static ActivityMainBinding bind(@NonNull View rootView) {
    // The body of this method is generated in a way you would not otherwise write.
    // This is done to optimize the compiled bytecode for size and performance.
    int id;
    missingId: {
      id = R.id.content;
      TextView content = ViewBindings.findChildViewById(rootView, id);
      if (content == null) {
        break missingId;
      }

      id = R.id.postMes;
      Button postMes = ViewBindings.findChildViewById(rootView, id);
      if (postMes == null) {
        break missingId;
      }
      return new ActivityMainBinding((LinearLayout) rootView, content, postMes);
    }
    String missingId = rootView.getResources().getResourceName(id);
    throw new NullPointerException("Missing required view with ID: ".concat(missingId));
  }

 /**
     * Like `findViewById` but skips the view itself.
     *
     * @hide
     */
    @Nullable
    public static <T extends View> T findChildViewById(View rootView, @IdRes int id) {
        if (!(rootView instanceof ViewGroup)) {
            return null;
        }
        final ViewGroup rootViewGroup = (ViewGroup) rootView;
        final int childCount = rootViewGroup.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final T view = rootViewGroup.getChildAt(i).findViewById(id);
            if (view != null) {
                return view;
            }
        }
        return null;
    }

  @NonNull
  private final LinearLayout rootView;

  @NonNull
  public final TextView content;

  @NonNull
  public final Button postMes;

  private ActivityMainBinding(@NonNull LinearLayout rootView, @NonNull TextView content,
      @NonNull Button postMes) {
    this.rootView = rootView;
    this.content = content;
    this.postMes = postMes;
  }

 dataBinding {
            enabled = true
        }

public class EventMessage extends BaseObservable {
    public String title;
    public EventMessage(){

    }
    public EventMessage(String title){
        this.title = title;
    }
    @Bindable
    public String getTitle() {
        return title;
    }
    /**
     * @param title*/
    public void setTitle(String title) {
        this.title = title;
        notifyPropertyChanged(BR.title);
    }
}

 android:text="@={viewModel.message.title}"

 android:onClick="@{viewModel.setText}"

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">

    <data>
        <variable
            name="viewModel"
            type="com.franzliszt.databinding.ViewModel" />

    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity"
        android:orientation="vertical"
        android:gravity="center">
        <EditText
            android:id="@+id/inputText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:hint="default"
            android:text="@={viewModel.message.title}"/>
        <TextView
            android:id="@+id/ShowText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text=""/>
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="update"
            android:onClick="@{viewModel.setText}"/>
    </LinearLayout>
</layout>

public class ViewModel {
    private ActivityMainBinding binding;
    public EventMessage message;
    public ViewModel(ActivityMainBinding binding, EventMessage message){
        this.binding = binding;
        this.message = message;
    }
    public void setText(View view){
        String str = message.getTitle();
        binding.ShowText.setText(str);
    }
}

 private ActivityMainBinding binding;

binding = DataBindingUtil.setContentView( this,R.layout.activity_main );
binding.setViewModel(new ViewModel(binding,new EventMessage()));