Android apps support three primary programming languages: Kotlin, Java, and C++. The core Android building blocks—four key components—remain foundational and stable for now.

Key Components

Service

Services handle background operations like music playback, dynamic wallpaper rendering, notification monitoring, screen savers, input methods, and accessibility support. While Google acknowledges limitations in service flexibility, widespread adoption means no major changes are planned.

Broadcast Receiver

A lightweight component primarily used as a gateway to other parts of your app, designed for minimal processing. For instance, it might trigger a JobService (via JobScheduler) to execute work based on an event. Implemented as a subclass of BroadcastReceiver, each broadcast is delivered as an Intent.

Note: From API 30 (Android R) onward, JobScheduler throttles apps with excessive scheduling calls (a sign of bugs), regardless of target SDK version.

Content Provider

Serves as a system-visible app entry point that exposes structured data items identified by URI schemas.

Component Launch Methods

For services:

• Android 5.0 (API 21+) supports JobScheduler for scheduling.
• Lower API levels still use startService or bindService. Always use explicit Intents to launch services; implicit Intents for bindService() will throw an exception starting from API 21.

Version Compatibility

To declare feature or API requierments for your app, use manifest tags:

<manifest ... >
    <uses-feature android:name="android.hardware.camera.any" android:required="true" />
    <uses-sdk android:minSdkVersion="7" android:targetSdkVersion="19" />
    ...
</manifest>

This declaration blocks installation on devices without a camera or Android versions below 2.1. If you're app uses a camera but doesn’t require it, set android:required="false" and check for camera availability at runtime before enabling camera features.