📱 How to Make Your First Android App in Java (Step by Step Guide)

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// Beginner Guide

✦ Beginner Java · Android Studio March 2026

Build Your First
Android App with Java

If you are a beginner and want to start Android development, this guide is perfect for you. We will build a simple Hello World Android App using Java — step by step, from scratch.

#Android #Java #HelloWorld #Beginner #AndroidStudio

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tutorials · guides · tips

6 steps 5 min read

This is just the beginning of your Android journey. Once you build this Hello World app, you'll understand the core structure of every Android project — and from there, the sky is the limit.

01

Install Android Studio 🛠️

First, you need to install Android Studio — the official IDE for Android development.

Download the installer: Go to the official Android Developers website and download the recommended Windows .exe installation file.

Run & follow the setup wizard:

• Double-click the downloaded .exe file. Click "Yes" if prompted by User Account Control.
• Click Next on the Welcome screen.
• On the Choose Components screen, keep both Android Studio and Android Virtual Device (AVD) checked.
• Accept the default installation location, then click Next → Install.
• Leave "Start Android Studio" selected and click Finish.

Complete the initial setup: Android Studio will launch the Setup Wizard to download SDK components. Choose Standard installation, select your preferred UI theme (Light or Darcula), agree to the license agreements, and click Finish to start the download.

02

Create a New Project 🚀

Once Android Studio is ready, follow these steps:

• Open Android Studio
• Click New Project
• Select Empty Activity → Click Next

Now fill in the project details:

Project Config

Project Name  →  MyFirstApp
Language      →  Java
Min SDK       →  API 21 (Android 5.0)
Package Name  →  com.example.myfirstapp

Click Finish and wait for the project to load. Gradle sync may take a minute.

03

Understand Project Structure 📱

After creating the project, you will see two important files in the left panel:

app / src / main /

MainActivity.java → Main logic file (Java code lives here)

res / layout / activity_main.xml → UI design file (layouts & views)

Every Android app follows this structure. The Java file controls behavior, the XML file controls the visual layout.

04

Design the UI (XML) 🎨

Open activity_main.xml and replace the existing code with the following:

XML — activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:textSize="24sp"
        android:layout_gravity="center" />

</FrameLayout>

The TextView widget displays text on the screen. We set it to center and give it a size of 24sp.

05

MainActivity Java Code 💻

Open MainActivity.java. The default generated code is already correct — make sure it looks like this:

Java — MainActivity.java

package com.example.myfirstapp;

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

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // This line connects MainActivity to activity_main.xml
        setContentView(R.layout.activity_main);
    }
}

The onCreate() method runs when the app starts. The setContentView() line loads your XML layout onto the screen.

06

Run Your App ▶️

Now it's time to run your app and see it in action!

• Open Device Manager from the toolbar and create a virtual device (emulator)
• Click the green Run ▶ button (or press Shift + F10)
• Wait for the Gradle build to complete — first build may take a few minutes
• Your app will launch on the emulator!

💡

Pro Tip: If the emulator runs slowly, enable Hardware Acceleration (HAXM) in Android Studio settings. Alternatively, connect a real Android phone via USB with USB Debugging enabled — it's much faster than the emulator.

// Expected Output

Hello World!

If everything is correct, you will see this on your screen 🎉

🎉

Congratulations!

You have successfully built your first Android app using Java. This is just the beginning — now you can move on to buttons, forms, navigation, and full applications.

🚀

Bonus Tip: Practice daily and you can easily start building real-world Android apps within 1–2 months. Try adding a Button next — when clicked, change the text of the TextView. That's your next challenge!

Android Dev Blog · Built for Beginners · 2026