Frequently Asked Questions
Kotlin
Kotlin is a modern, expressive language officially supported by Google for Android. It offers null safety, concise syntax, and full Java interoperability.
Kotlin uses nullable types and safe calls (?.) to prevent NullPointerExceptions. Use
? for nullable types and !! only when you are sure a value is not null.
Extension functions let you add new functions to existing classes without modifying their source code, making your code more readable and modular.
Coroutines provide a way to write asynchronous code sequentially. Use
launch and async builders with suspend functions for concurrency.
Data classes are used to hold data. They automatically provide
equals(), hashCode(), and toString() methods.
Sealed classes restrict class hierarchies, making them useful for representing restricted states or results in a type-safe way.
Higher-order functions take functions as parameters or return them. They are used for callbacks, functional programming, and DSLs in Kotlin.
Kotlin collections support powerful operations like
map, filter, and reduce using lambda expressions.
Jetpack Compose
Jetpack Compose is Android’s modern UI toolkit for building native interfaces with Kotlin code instead of XML.
Use the
@Composable annotation on a function. For example: @Composable fun Greeting(name: String) { Text(text = "Hello $name!") }
Use
remember and mutableStateOf to manage local state. For shared state, use ViewModel and state hoisting.
Use
LazyColumn for efficient, scrollable lists. Each item is a composable.
Use
animate*AsState functions and AnimatedVisibility for smooth UI animations.
Use
MaterialTheme and custom color palettes to style your app consistently.
Use the
@Preview annotation to preview composables in the IDE without running the app.
Use the
Navigation component for Compose to manage in-app navigation with composable destinations.
Firebase
Firebase is a suite of cloud services for Android, including authentication, database, analytics, and messaging.
Use the Firebase Console to register your app, then add the
google-services.json file and dependencies to your project.
Firestore is a scalable, flexible NoSQL cloud database. It supports richer queries and offline sync compared to Realtime Database.
Add Firebase Auth to your app and use its SDK to sign in users with email, Google, or other providers.
Use Firebase Cloud Messaging (FCM) to send notifications to users. Integrate the FCM SDK and use the console or server APIs.
Add Firebase Analytics to track user behavior and events in your app for better insights.
Use Firebase Security Rules to restrict access and validate data before writing to the database.
Remote Config lets you change app behavior and appearance without publishing an update, by fetching values from the cloud.
Jetpack
Android Jetpack is a suite of libraries to help developers follow best practices and write robust, maintainable code.
ViewModel stores and manages UI-related data in a lifecycle conscious way, surviving configuration changes.
LiveData is an observable data holder class. UI components observe LiveData to react to data changes automatically.
Room is a persistence library that provides an abstraction layer over SQLite for easier database access.
Navigation Component simplifies navigation and passing data between destinations in your app.
WorkManager is used for background tasks that need guaranteed execution, even if the app exits or device restarts.
Paging library helps you load and display large data sets efficiently by loading data in chunks or pages.
Hilt is a dependency injection library for Android that reduces boilerplate and integrates with Jetpack components.
General
Start by learning Kotlin, then follow beginner Android tutorials and build simple apps to practice.
Android Studio, a good computer, and a willingness to learn are essential for Android development.
Use unit tests, UI tests (Espresso), and manual testing on emulators and real devices.
Create a developer account, prepare your APK/AAB, fill in the store listing, and submit for review on the Google Play Console.
Use Android Studio Profiler and logcat to identify and fix bottlenecks in your app.
Use responsive layouts, constraint layouts, and provide different resources for various screen densities and sizes.
Request permissions at runtime and explain why they are needed. Handle permission denial gracefully.
Use string resources and provide translations for different languages in the
res/values folders.