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

This example demonstrates how do I pass an arrayList to another activity using intends in android.

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="https://schemas.android.com/apk/res/android"
   xmlns:tools="https://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:id="@+id/relativeLayout"
   tools:context=".MainActivity">
   <Button
      android:id="@+id/button"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Pass array to 2nd Activity"
      android:layout_centerInParent="true" />
</RelativeLayout>

Step 3 − Add the following code to src/MainActivity.java

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity{
   Button button;
   ArrayList<String> numbers = new ArrayList<>();
   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      button = findViewById(R.id.button);
      button.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            numbers.add("ONE");
            numbers.add("TWO");
            numbers.add("THREE");
            numbers.add("FOUR");
            numbers.add("FIVE");
            Intent intent = new Intent(MainActivity.this, SecondActivity.class);
            intent.putExtra("key", numbers);
            startActivity(intent);
         }
      });
   }
}

Step 4 – Create a new Activity(SecondActivity) and add the following code in SecondActivity.java

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
import java.util.ArrayList;
public class SecondActivity extends AppCompatActivity {
   TextView textView;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_second);
      textView = findViewById(R.id.textView);
      ArrayList<String> numbersList = (ArrayList<String>) getIntent().getSerializableExtra("key");
      textView.setText(String.valueOf(numbersList));
   }
}

Step 5 – Add the following code in the activity_second.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="https://schemas.android.com/apk/res/android"
   xmlns:tools="https://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context=".SecondActivity">
   <TextView
      android:id="@+id/textView"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:text=""
      android:textSize="24sp"
      android:textStyle="bold"/>
</RelativeLayout>

Step 6 - Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="https://schemas.android.com/apk/res/android" package="app.com.sample">
   <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=".SecondActivity"></activity>
      <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  Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen –