Back to MainActivity from Second Activity

 MainActivity.java

package com.example.backtomainactivity;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button secondActivity=findViewById(R.id.secondActivity);
        secondActivity.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent secondActivityIntent=new Intent(MainActivity.this,SecondActivity.class);
                startActivity(secondActivityIntent);
            }
        });
    }
}

SecondActivity.java

package com.example.backtomainactivity;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class SecondActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
       Button back=findViewById(R.id.backtoMain);
        back.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
               // finishAffinity();

                finishAndRemoveTask();
            }
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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">

    <Button
        android:id="@+id/secondActivity"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="SecondActivity"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

activity_second.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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=".SecondActivity">

    <Button
        android:id="@+id/backtoMain"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Back"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

Video Links:

Project Links:https://drive.google.com/file/d/1yZygIlptmKq6kI2kyvWT0_99tmOZDC4N/view?usp=sharing