Welcome to Day 4 of the 90-Day Android Developer Roadmap at HandsOnAndroid! 👋
In Day 1, we covered the roadmap.
In Day 2, you installed Android Studio.
In Day 3, we chose Kotlin.
Today, it’s time to build your first Android app! 🎉
🛠️ Step-by-Step: Create Your First Android App
🔹 Step 1: Open Android Studio
Launch Android Studio and click “New Project.”
🔹 Step 2: Select “Empty Activity”
Choose “Empty Activity” → click Next
🔹 Step 3: Configure the App
- Name: HelloAndroid
- Language: Kotlin
- Minimum SDK: API 21 (Lollipop)
- ✅ Click Finish
🔹 Step 4: Understand the Project Structure
MainActivity.kt: Your entry point (Kotlin file)res/layout/activity_main.xml: Your app’s layout (UI)AndroidManifest.xml: App declaration info
🔹 Step 5: Update Layout XML
Open activity_main.xml and replace the content:
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello, Android!"
android:layout_gravity="center"
android:textSize="24sp" />
🔹 Step 6: Run the App
Click ▶️ Run → Select Emulator → See the magic! 🎉
📷 Preview
Once the app runs on the emulator, you’ll see:
🟢 “Hello, Android!” centered on a white screen.
That’s it — your first Android app is live! 🚀
🧠 What You Learned Today
- Creating a new Android project
- Basic Kotlin Activity + XML layout
- Running your app in an emulator