Add a Back Button to Action Bar android studio

In this tutorial we will add a back button in action bar, when it is clicked it will go to previous activity(the app will close if this was launcher activity). We will go from main activity to new activity by clicking button in main activity. In new activity we will add a back button to actionbar when that button is clicked the main activity will appear...

Step 1: Create a new Project of open existing project:

Step 2: activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:gravity="center"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/button"
        android:text="New Activity"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

Step 3: MainActivity.java

package com.blogspot.devofandroid.myapplication;


import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
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 button = (Button)findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startActivity(new Intent(MainActivity.this, NewActivity.class));
            }
        });

    }

}

Step 4: activity_new.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    android:gravity="center"
    tools:context=".NewActivity">

    <TextView
        android:text="Click back buttoon of actionbar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

Step 5: NewActivity.java

package com.blogspot.devofandroid.myapplication;

import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class NewActivity extends AppCompatActivity {

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

        //actionbar
        ActionBar actionBar = getSupportActionBar();
        //set actionbar title(Optional)
        actionBar.setTitle("New Activity");
        //set back button
        actionBar.setDisplayHomeAsUpEnabled(true);
        actionBar.setDisplayShowHomeEnabled(true);
    }

    //handle onBack pressed(go previous activity)
    @Override
    public boolean onSupportNavigateUp() {
        onBackPressed();
        return true;
    }

}

Step 6: Output