Creating a simple ‘Hello World’ application is the traditional way to start learning a new programming language or platform. In this blog, we’ll walk you through the process of creating your first Android application that displays the text “Hello, World!”.

Step 1: Create a New Project

Open Android Studio and select New Project. In the New Project dialog box, choose Empty Activity, and then click Next.

Step 2: Configure Your Project

On the Configure your project page, fill in the following fields:

• Name: Hello World
• Package name: in.infovistar.helloworld
• Save location: Choose a location on your computer to save the project.
• Language: Java
• Minimum SDK: API 21: Android 5.0 (Lollipop)

Click Finish to create your project.

Step 3: Update the Layout File

Navigate to the activity_main.xml file located in app > res > layout. This XML file defines the layout for the activity’s user interface (UI). Replace the existing code with the following:

<?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">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="Hello, World!"
        android:textSize="30sp" />

</RelativeLayout>

Step 4: Main Activity File

The main activity code is a Java file MainActivity.java. This is the actual application file which ultimately gets converted to a Dalvik executable and runs your application. Following is the default code generated by the application wizard for Hello World! application −

package in.infovistar.helloworld;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
   }
}

Step 5: Manifest File

When developing an application, it is important to declare all components in a manifest.xml file located at the root of the project directory. This file serves as an interface between the Android operating system and your application. If a component is not declared in this file, it will not be recognized by the OS. A default manifest file will typically look like the following example.

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

   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      
      <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>

Congratulations on developing your first Android application! Follow the tutorial step-by-step to become a great Android developer. Best of luck!