How to pass data between activities in Android?

This example demonstrates how do I pass data between activities 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="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=".MainActivity">
   <Button
      android:id="@+id/btnPassData"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_above="@id/btnReturnData"
      android:layout_marginBottom="16dp"
      android:text="Pass Data To Second Activity" />
   <Button
      android:id="@+id/btnReturnData"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:text="Pass Data To Next Activity And Get back data!"/>
   <TextView
      android:id="@+id/resultDataTextView"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_below="@id/btnReturnData"
      android:layout_marginTop="16dp"
      android:textSize="20sp"/>
</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 android.widget.TextView;
public class MainActivity extends AppCompatActivity {
   private final static int REQUEST_CODE_1 = 1;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      Button button = findViewById(R.id.btnPassData);
      button.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            Intent intent = new Intent(MainActivity.this, SecondActivity.class);
            intent.putExtra("message", "This message comes from passing data from Main " + "Activity");
            startActivity(intent);
         }
      });
      Button passDataReturnResultSourceButton = findViewById(R.id.btnReturnData);
      passDataReturnResultSourceButton.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View view) {
            Intent intent = new Intent(MainActivity.this, SecondActivity.class);
            intent.putExtra("message", "This message comes from the MainActivity second button");
            startActivityForResult(intent, REQUEST_CODE_1);
         }
      });
   }
   @Override
   protected void onActivityResult(int requestCode, int resultCode, Intent dataIntent) {
      super.onActivityResult(requestCode, resultCode, dataIntent);
      switch (requestCode) {
         case REQUEST_CODE_1: TextView textView = findViewById(R.id.resultDataTextView);
         if (resultCode == RESULT_OK) {
            String messageReturn = dataIntent.getStringExtra("message_return");
            textView.setText(messageReturn);
         }
      }
   }
}
Step 4 − Add the following code to res/layout/activity_second.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:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context=".SecondActivity">
   <Button
      android:id="@+id/btnReturnData"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:text="Pass Data Back To Main Activity"/>
   <TextView
      android:layout_below="@id/btnReturnData"
      android:layout_marginTop="8dp"
      android:id="@+id/tvReturnData"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:textSize="20dp"/>
</RelativeLayout>
Step 5 − Add the following code to src/SecondActivity.java
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class SecondActivity extends AppCompatActivity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_second);
      Intent intent = getIntent();
      String message = intent.getStringExtra("message");
      TextView textView = findViewById(R.id.tvReturnData);
      textView.setText(message);
      Button passDataTargetReturnDataButton = findViewById(R.id.btnReturnData);
      passDataTargetReturnDataButton.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View view) {
            Intent intent = new Intent();
            intent.putExtra("message_return", "This data is returned when user click button in target activity.");
            setResult(RESULT_OK, intent);
            finish();
         }
      });
   }
   @Override
   public void onBackPressed() {
      Intent intent = new Intent();
      intent.putExtra("message_return", "This data is returned when user click back menu in target activity.");
      setResult(RESULT_OK, intent);
      finish();
   }
}
Step 6 − 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.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 −
Click here to download the project code.