Android developer interview questions

Android developer interview questions and answers

Android interviews focus on the app lifecycle, Kotlin, modern architecture with Jetpack and how you keep apps fast and stable. These are the questions asked most, with what each one checks.

What to revise before the interview

  • Activity and fragment lifecycles
  • Kotlin: null safety, data classes, extension functions
  • Coroutines and Flow
  • MVVM with ViewModel and LiveData or StateFlow
  • Jetpack Compose basics and state
  • Room database and Retrofit
  • Configuration changes and process death
  • Performance: ANRs, memory leaks, RecyclerView

  1. 1.Explain the Activity lifecycle.

    What they're checking
    The most basic Android question.
    How to answer
    onCreate, onStart, onResume (in the foreground), onPause, onStop, onDestroy. Give a practical example: pause a video in onPause, release the camera in onStop.

  2. 2.What happens on a screen rotation, and how do you keep state?

    What they're checking
    A common source of bugs.
    How to answer
    By default the activity is destroyed and recreated. Keep UI state in a ViewModel, which survives configuration changes, and use SavedStateHandle for state that must survive process death.

  3. 3.What makes Kotlin safer than Java for Android?

    What they're checking
    Kotlin is the default; this checks you know why.
    How to answer
    Null safety in the type system (String vs String?), data classes, sealed classes for states, extension functions and coroutines for simpler async code.

  4. 4.What are coroutines, and what is a coroutine scope?

    What they're checking
    Modern async on Android.
    How to answer
    Coroutines let you write async code sequentially with suspend functions. A scope ties their lifetime to something - viewModelScope cancels work when the ViewModel is cleared, which avoids leaks.

  5. 5.Explain MVVM on Android.

    What they're checking
    Architecture understanding.
    How to answer
    The View observes state from a ViewModel; the ViewModel gets data from a repository, which talks to Room and the network. It keeps logic out of activities and makes it testable.

  6. 6.LiveData vs StateFlow?

    What they're checking
    Current best practice.
    How to answer
    Both hold observable state. LiveData is lifecycle-aware out of the box; StateFlow is Kotlin-first, works outside Android and fits coroutines - collect it with repeatOnLifecycle or collectAsState in Compose.

  7. 7.How does state work in Jetpack Compose?

    What they're checking
    Compose is now standard for new UI.
    How to answer
    Composables re-run when the state they read changes. Use remember and mutableStateOf for local state, hoist state up to make components reusable, and keep screen state in a ViewModel.

  8. 8.How do you avoid ANRs?

    What they're checking
    App quality awareness.
    How to answer
    Never block the main thread: do disk, network and heavy work on background dispatchers (Dispatchers.IO), and keep onCreate light. Use StrictMode during development to catch mistakes.

  9. 9.What causes memory leaks in Android, and how do you find them?

    What they're checking
    Debugging experience.
    How to answer
    Holding a reference to an Activity or Context beyond its life - in a static field, a long-running callback or a singleton. Find them with LeakCanary and the Android Studio profiler.

  10. 10.Tell me about an app you built.

    What they're checking
    Real experience.
    How to answer
    Cover the architecture, libraries (Retrofit, Room, Hilt), one hard problem and whether it's on the Play Store. Numbers help: downloads, rating, crash-free rate.

On a live call, Cuelyte AI hears questions like these and has an answer ready in about a second, built from your resume and notes. Coding interviews: how Cuelyte AI helps

Frequently asked questions

Should I learn Java or Kotlin for Android interviews?

Kotlin. It is Google's recommended language for Android, and most new code and interviews use it. Knowing Java helps with older codebases.

Is Jetpack Compose asked in interviews?

More and more. Know composables, state, recomposition and how Compose works with ViewModels. XML views are still asked for older apps.

Do Android interviews include DSA?

At product companies, usually yes - a coding round alongside Android-specific rounds.

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