Data Binding Example kotlin

1/  Open build.gradle file ( app module) 

   1.1/Add the following code in android block

buildFeatures{
    dataBinding = true
}

   1.2/Add the following code in plugins block

id("kotlin-kapt")

below is the full code of the gradle file 

plugins {
    alias(libs.plugins.android.application)
    alias(libs.plugins.kotlin.android)
    id("kotlin-kapt")
}

android {
    namespace = "com.microappvalley.databindingkotlin"
    compileSdk = 35

    defaultConfig {
        applicationId = "com.microappvalley.databindingkotlin"
        minSdk = 24
        targetSdk = 34
        versionCode = 1
        versionName = "1.0"

        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            isMinifyEnabled = false
            proguardFiles(
                getDefaultProguardFile("proguard-android-optimize.txt"),
                "proguard-rules.pro"
            )
        }
    }
    compileOptions {
        sourceCompatibility = JavaVersion.VERSION_1_8
        targetCompatibility = JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = "1.8"
    }
    buildFeatures{
        dataBinding = true
    }
}

dependencies {

    implementation(libs.androidx.core.ktx)
    implementation(libs.androidx.appcompat)
    implementation(libs.material)
    implementation(libs.androidx.activity)
    implementation(libs.androidx.constraintlayout)
    testImplementation(libs.junit)
    androidTestImplementation(libs.androidx.junit)
    androidTestImplementation(libs.androidx.espresso.core)
}

After changes to the gradle file, you must sync your project.

2/Create Kotlin data class: User

package com.microappvalley.databindingkotlin

data class User(var name: String, var email: String)

3/ Modify your activity_main.xml file. 

   3.1/ Convert root layout into layout tag
   3.2/ Add data tag
   3.3/ Add a variable in the data tag ( give a variable name and type ) in the example create a User model and set the model in the variable tag.

   3.4/ Where do we need to set the user data we use this syntax @{user.name} Here, the user is the model and the name is the field of this model

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

    <data>
        <variable
            name="user"
            type="com.microappvalley.databindingkotlin.User" />
    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"

        >
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            android:orientation="vertical"
            android:gravity="center"
            app:layout_constraintBottom_toBottomOf="parent"
            >
            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                >
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="Name:"
                    android:textSize="18sp"
                    android:textStyle="bold"
                    />
                <TextView
                    android:layout_marginStart="16dp"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@{user.name}"
                    android:textSize="18sp"
                    />
            </LinearLayout>
            <LinearLayout
                android:layout_marginTop="16dp"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                >
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="Email:"
                    android:textSize="18sp"
                    android:textStyle="bold"
                    />
                <TextView
                    android:layout_marginStart="16dp"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@{user.email}"
                    android:textSize="18sp"
                    />
            </LinearLayout>

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


</layout>

4/ Modify your MainActivity.kt file

package com.microappvalley.databindingkotlin

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

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

        val user = User("Test User", "test.user@example.com")

        binding.user = user

    }
}

Here first you should bind your XML file.

With the data binding, automatically create a file with the same name as the XML file just adding the Binding last of the XML file

in the above example, the XML file name is activity_main
and view binding create a file name ActivityMainBinding

after binding the views we can bind the data source

in the example, the user object is bind with the views data variable 

val user = User("Test User", "test.user@example.com")
binding.user = user

Output: