Android Studio, Project Structure & First App

Install Android Studio

Android Studio is the official IDE. It bundles the SDK, an emulator, and the Gradle build system. Install it, open it once so it downloads the SDK, then create a new project with Empty Views Activity and language Kotlin.

Project structure explained

• app/src/main/java/ — your Kotlin code (Activities, classes).
• app/src/main/res/layout/ — XML screen layouts.
• res/values/ — strings, colors, themes.
• res/drawable/ — images and shapes.
• AndroidManifest.xml — app declaration.
• build.gradle (Module: app) — dependencies and SDK versions.

Gradle and dependencies

Gradle builds your app. You add libraries in the module build.gradle:

dependencies {
    implementation("androidx.core:core-ktx:1.13.1")
    implementation("androidx.appcompat:appcompat:1.7.0")
    implementation("com.google.android.material:material:1.12.0")
}

Run your app

Create an emulator in Device Manager or plug in a real phone with USB debugging on, then press ▶ Run.

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }
}

Tip: minSdk sets the oldest Android version you support; targetSdk is the version you built and tested against. Keep targetSdk current for Play Store.