How to pass an arrayList to another activity using intents in Android Kotlin?

This example demonstrates how to pass an arrayList to another activity using intents in Android Kotlin.
Step 1 − Create a new project in Android Studio, go to File ? New Project and fill all required details to create a new project.
Step 2 − Add the following code to res/layout/activity_main.xml.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
   android:id="@+id/relativeLayout"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context=".MainActivity">
   <TextView
      android:id="@+id/textView"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="50dp"
      android:padding="8dp"
      android:text="Tutorials Point"
      android:textColor="@color/colorPrimaryDark"
      android:textSize="48sp"
      android:textStyle="bold" />
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@id/textView"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="50dp"
      android:padding="8dp"
      android:text="Passing an arrayList to another activity using intents"
      android:textAlignment="center"
      android:textColor="@android:color/holo_red_dark"
      android:textSize="24sp"
      android:textStyle="bold" />
   <Button
      android:id="@+id/button"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:background="@android:color/holo_red_dark"
      android:padding="4dp"
      android:text="Pass array to 2nd Activity"
      android:textColor="@android:color/background_light"
      android:textStyle="bold" />
</RelativeLayout>
Step 3 − Add the following code to src/MainActivity.kt
import android.content.Intent
import android.os.Bundle
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
   lateinit var button: Button
   var numbers: ArrayList<String> = ArrayList()
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      button = findViewById(R.id.button)
      button.setOnClickListener {
         numbers.add("ONE")
         numbers.add("TWO")
         numbers.add("THREE")
         numbers.add("FOUR")
         numbers.add("FIVE")
         val intent = Intent(this@MainActivity, SecondActivity::class.java)
         intent.putExtra("key", numbers)
         startActivity(intent)
      }
   }
}
Step 4 − Create a new Activity and add the following code −
import androidx.appcompat.app . AppCompatActivity
import android.os . Bundle
import android.widget . TextView
class SecondActivity : AppCompatActivity() {
   private lateinit var textView : TextView
   override fun onCreate ( savedInstanceState : Bundle ?) {
      super .onCreate( savedInstanceState )
      setContentView( R . layout . activity_second )
      textView = findViewById( R . id . textView )
      val numberList = intent .getSerializableExtra( "key" )
      textView . text = numberList .toString()
   }
}
<RelativeLayout xmlns: android ="http://schemas.android.com/apk/res/android"
xmlns: tools ="http://schemas.android.com/tools"
   android :layout_width ="match_parent"
   android :layout_height ="match_parent"
   tools :context =".SecondActivity" >
   <TextView
      android :layout_width ="wrap_content"
      android :layout_height ="wrap_content"
      android :layout_centerHorizonta l ="true"
      android :layout_marginTop ="90dp"
      android :padding ="8dp"
      android :text ="Second Activity"
      android :textAlignment ="center"
      android :textColor ="@android:color/holo_red_dark"
      android :textSize ="24sp"
      android :textStyle ="bold" />
   <TextView
      android :id ="@+id/textView"
      android :layout_width ="wrap_content"
      android :layout_height ="wrap_content"
      android :layout_centerInParent ="true"
      android :textColor ="@android:color/background_dark"
      android :textSize ="24sp"
      android :textStyle ="bold" />
</RelativeLayout>
Step 5 − Add the following code to androidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="app.com.myapplication">
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <activity android:name=".MainActivity">
         <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>
Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click the Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen