diff --git a/.idea/gradle.xml b/.idea/gradle.xml
index 18de3ac..23a89bb 100644
--- a/.idea/gradle.xml
+++ b/.idea/gradle.xml
@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="GradleMigrationSettings" migrationVersion="1" />
   <component name="GradleSettings">
     <option name="linkedExternalProjectsSettings">
       <GradleProjectSettings>
diff --git a/app/build.gradle b/app/build.gradle
index 2b9d8a3..16316db 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -1,8 +1,7 @@
 plugins {
     id 'com.android.application'
     id 'kotlin-android'
-    /*TODO step1 kotlin kapt 추가하기
-    *  코틀린 어노테이션을 사용하기 위함*/
+    id 'kotlin-kapt'
 }
 
 android {
@@ -32,7 +31,9 @@ android {
     kotlinOptions {
         jvmTarget = '1.8'
     }
-    /*TODO step2 DataBinding 활성화 하기*/
+    dataBinding {
+        enabled = true
+    }
 }
 
 dependencies {
diff --git a/app/src/main/java/sotp/semina/practicegitanddatabinding/MainActivity.kt b/app/src/main/java/sotp/semina/practicegitanddatabinding/MainActivity.kt
index 1b2442c..3496829 100644
--- a/app/src/main/java/sotp/semina/practicegitanddatabinding/MainActivity.kt
+++ b/app/src/main/java/sotp/semina/practicegitanddatabinding/MainActivity.kt
@@ -4,13 +4,21 @@ import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
 import android.widget.Button
 import android.widget.EditText
+import android.widget.ImageView
 import android.widget.TextView
+import androidx.databinding.BindingAdapter
+import androidx.databinding.DataBindingUtil
 import com.bumptech.glide.Glide
-/*TODO step4 데이터 바인딩 직접 적용해보기.*/
+import sotp.semina.practicegitanddatabinding.databinding.ActivityMainBinding
+
 class MainActivity : AppCompatActivity() {
+    private lateinit var binding: ActivityMainBinding
+    var profilename = "profileName"
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        setContentView(R.layout.activity_main)
+        binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
+        binding.mainActivity = this
         initView()
     }
 
@@ -20,18 +28,20 @@ class MainActivity : AppCompatActivity() {
         addButtonClickEvent()
     }
 
+
     private fun initProfileImage() {
         Glide.with(this)
             .load(IMAGE_URL)
-            .into(findViewById(R.id.image_profile_image))
+            .into(binding.imageProfileImage)
     }
 
     private fun setProfileName(content:String) {
-        findViewById<TextView>(R.id.text_profile_name).text = content
+        profilename = content
+        binding.invalidateAll()
     }
 
     private fun addButtonClickEvent() {
-        findViewById<Button>(R.id.button_profile_change_button).setOnClickListener {
+        binding.buttonProfileChangeButton.setOnClickListener {
             setProfileName(getEditTextToString(findViewById(R.id.input_changed_profile)))
         }
     }
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
index 47724c3..1bf6122 100644
--- a/app/src/main/res/layout/activity_main.xml
+++ b/app/src/main/res/layout/activity_main.xml
@@ -1,57 +1,63 @@
 <?xml version="1.0" encoding="utf-8"?>
-<!--TODO step3 데이터 바인딩을 위한 레이아웃으로 감싸기-->
-<androidx.constraintlayout.widget.ConstraintLayout
-    xmlns:android="http://schemas.android.com/apk/res/android"
+<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"
-    android:layout_width="match_parent"
-    android:layout_height="match_parent"
-    tools:context=".MainActivity">
+    xmlns:tools="http://schemas.android.com/tools">
 
-    <ImageView
-        android:id="@+id/image_profile_image"
-        android:layout_width="200dp"
-        android:layout_height="200dp"
-        android:layout_marginTop="100dp"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toTopOf="parent"
-        tools:src = "@mipmap/ic_launcher"
-        />
+    <data>
+        <variable
+            name="mainActivity"
+            type="sotp.semina.practicegitanddatabinding.MainActivity" />
+    </data>
 
-    <TextView
-        android:id="@+id/text_profile_name"
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:layout_marginTop="16dp"
-        android:textColor="@color/black"
-        android:textSize="20sp"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toBottomOf="@+id/image_profile_image"
-        tools:text="profile name" />
-
-    <EditText
-        android:id="@+id/input_changed_profile"
+    <androidx.constraintlayout.widget.ConstraintLayout
         android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:layout_marginStart="16dp"
-        android:layout_marginTop="16dp"
-        android:layout_marginEnd="16dp"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toBottomOf="@+id/text_profile_name" />
+        android:layout_height="match_parent"
+        tools:context=".MainActivity">
 
-    <Button
-        android:id="@+id/button_profile_change_button"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:layout_marginStart="16dp"
-        android:layout_marginTop="16dp"
-        android:layout_marginEnd="16dp"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent"
-        android:text="Change"
-        app:layout_constraintTop_toBottomOf="@+id/input_changed_profile" />
+        <ImageView
+            android:id="@+id/image_profile_image"
+            android:layout_width="200dp"
+            android:layout_height="200dp"
+            android:layout_marginTop="100dp"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="parent"
+            tools:src="@mipmap/ic_launcher" />
+
+        <TextView
+            android:id="@+id/text_profile_name"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="16dp"
+            android:textColor="@color/black"
+            android:textSize="20sp"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/image_profile_image"
+            tools:text="@{mainActivity.profilename}" />
+
+        <EditText
+            android:id="@+id/input_changed_profile"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="16dp"
+            android:layout_marginTop="16dp"
+            android:layout_marginEnd="16dp"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/text_profile_name" />
+
+        <Button
+            android:id="@+id/button_profile_change_button"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="16dp"
+            android:layout_marginTop="16dp"
+            android:layout_marginEnd="16dp"
+            android:text="Change"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@+id/input_changed_profile" />
 
-</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
+    </androidx.constraintlayout.widget.ConstraintLayout>
+</layout>
\ No newline at end of file