Android Toolbar (ActionBar) - Tutorial

//it will make after MainActivity
//make ChildActivity.java
package com.example.codeforactionbar;

import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

public class ChildActivity extends AppCompatActivity {

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

        ActionBar actionbar = getSupportActionBar();
        actionbar.setTitle("Home");
        actionbar.setSubtitle("Back to home page");
        actionbar.setHomeButtonEnabled(true);
    }
}






//AndroidManifest.xml
//mkae sure Write   <activity android:name=".ChildActivity"  android:parentActivityName=".MainActivity" />
//set parent Activity & child Activity in android manifest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.codeforactionbar">

    <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=".ChildActivity"
             android:parentActivityName=".MainActivity" />

        <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>