dataBinding {
        enabled = true
    }

package com.example.databinding

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.databinding.DataBindingUtil
import com.example.databinding.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {
    lateinit var binding : ActivityMainBinding
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = DataBindingUtil.setContentView(this,R.layout.activity_main)

        val  user : User = User("park","eunji")
        binding.user=user
    }
}

package com.example.databinding

class User {
    var firstName:String
    var lastName:String

    constructor(firstName:String, lastName:String){
        this.firstName=firstName
        this.lastName=lastName
    }
}

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

    <data>
        <variable
            name="user"
            type="com.example.databinding.User" />
    </data>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

    <TextView
        android:id="@+id/firstname_textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@{user.firstName, default=defaults}" />

    <TextView
        android:id="@+id/lastname_textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@{user.lastName, default=defaults}" />

    </LinearLayout>

</layout>

결과물

메인액티비티.kt에서

binding.firstname_textView.setText=user.firstName

binding.lastname_textView.setText=user.lastName

해줘야 하는 것을 xml에 작성함으로써 액티비티 소스코드가 깔끔해졌다.