android dataBinding数据绑定2-ObservableField

<?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="cat"
            type="com.example.kkk.Cat" />
        <variable
            name="myHandle"
            type="com.example.kkk.MainActivity.MyHandle" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

        <TextView
            android:layout_width="200dp"
            android:layout_height="200dp"
            android:text="@{cat.catName}"
            android:onClick="@{()->myHandle.nameClick()}"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

    </androidx.constraintlayout.widget.ConstraintLayout>
</layout>

package com.example.kkk;

import androidx.databinding.ObservableField;

public class Cat {

    private ObservableField<String> catName;
    private ObservableField<Integer> age;

    public Cat(String catName, int age) {
        this.catName = new ObservableField<>(catName);
        this.age = new ObservableField<>(age);
    }
    
    public ObservableField<String> getCatName() {
        return catName;
    }

    public void setCatName(String catName) {
        this.catName.set(catName);
    }

    public ObservableField<Integer> getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age.set(age);
    }






}

package com.example.kkk;

import androidx.appcompat.app.AppCompatActivity;
import androidx.databinding.DataBindingUtil;

import android.os.Bundle;

import com.example.kkk.databinding.ActivityMainBinding;

public class MainActivity extends AppCompatActivity {

    private Cat cat;
    private MyHandle myHandle;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
        cat = new Cat("小明",30);
        binding.setCat(cat);

        myHandle = new MyHandle();
        binding.setMyHandle(myHandle);
    }

    public class MyHandle{
        public void nameClick(){
            cat.setCatName("哈哈哈123");
        }
    }
}