Lesson 3: Understanding the Anatomy of an Android Project

Understanding the Anatomy of an Android Project

Your new project has a lot of generated files. You don't need to understand all of it today, but knowing what's what will save you a lot of confusion.

The important folders

app/
├── src/main/
│   ├── java/com/example/tasklist/   ← your Kotlin code lives here
│   │   └── MainActivity.kt
│   ├── res/                          ← images, strings, icons
│   └── AndroidManifest.xml           ← describes your app to the OS
└── build.gradle.kts                  ← dependencies and build config

MainActivity.kt — your app's entry point

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            // Your Compose UI goes here
        }
    }
}

When the OS launches your app, this is the first code that runs. setContent { } is where you tell Android what to actually draw on screen — we'll fill this in properly in lesson 6.

AndroidManifest.xml

This file declares what your app needs to work: which screens (Activities) exist, what permissions it requires (camera, internet, etc.), and its name/icon. You'll edit this occasionally — for now, just know it exists and it's where permissions get declared later in the course.

build.gradle.kts — your dependency list

This is where you declare external libraries your app depends on (like the networking and database libraries we'll add later). Every time you add a new library, this is the file you edit, followed by clicking "Sync Now."

The res/ folder

Short for "resources" — this holds anything that isn't code: app icons, string text (for supporting multiple languages later), and colors. We'll use res/values/strings.xml briefly, but Compose handles most UI directly in code rather than in XML.

Next: Lesson 4 — the Kotlin fundamentals this course leans on most.