/android-interview

Questions for Android Engineer Interview

android-interview

Android Engineer Interview Questions

Kotlin

  • What is the difference between const val and val?
  • What is so interesting about data class?
  • Is singleton thread-safe? vs Object?
  • What are different type of scope modifiers?
  • What are different Coroutine Scope?
  • How to manage series and parallel execution?
  • Difference between Flow/SharedFlow/StateFlow and elaborate it.
  • What happens if we call .cancel() from a coroutine scope?

Android

  • How does Garbage collection works?
  • What is a dangling pointer?
  • Elaborate Memory Leak?
  • Explain fragment Lifecycle when it comes to ViewPager and sliding between different fragments.
  • Difference between FragmentStateAdapter and FragmentStatePagerAdapter.

Lifecycle

  • How to keep a video maintain playing state when we rotate screen?
  • How many callbacks in Fragmnets?
  • What could be the reasons when onPause didn't get triggered?
  • What kind of events trigger onPause() to run?
  • In what scenario does the "onDestory" get called directly after "onCreate"?
  • Which callback gets called on Activity when an AlertDialog is shown?
  • What's the lifecycle in PIP (Picture-in-Picture)?
  • What happens if you rotate the device?
  • Inside a viewpager (Fragment state pager adapter) what will be the lifecycle of the fragments when you swap from tab to another ?
  • Why onActivityCreated is now depreciated in Fragment?
  • Which callback should i use if i want to know when my activity came to foreground?
  • When is onActivityResult called?
  • What does setRetainInstance do and how you can avoid it?
  • What callbacks trigger when a Dialog opens up? Conside both case, dialog attached from same activity/fragment and other activity/fragment.
  • What does launchWhenCreated, launchWhenStarted, and launchWhenResumed functions do?

Networking

  • What is the role of OkHttp and Retroifit?
  • What design pattern is Retroifit?

Dependency Injection

  • Provides vs binds
  • Subcomponent vs component dependency, what is the difference under the hood
  • What is subcomponent and what is the use? How do you use qualifiers or how would you provide different instances of a class with the same data type? Constructor Injection V/s Method Injection? What is the scope? Singleton Annotation?
  • What is Circular dependency in dagger?, and how to resolve it
  • What's interesting about Hilt?
  • Did you use Koin? What are your thoughts on it?

Android Compose

  • How to launch coroutine from a composable function? - LaunchedEffect
  • How to launch coroutine from a non-composable function, but tied to composition? - rememberCoroutineScope()
  • What is recomposition? Recomposition
  • Why and when to use remember {}?
  • Difference between LazyColumn and RecyclerView?
  • What is AndroidView in compose?
  • What is the lifecycle of composeables? Lifecycle
  • How to avoid recomposition of any composable, if the state is not changed? Smart Recomposition
  • What are stable types which can skip recomposition?
  • What is State?
  • What is MutableState and how does recomposition happens?
  • How to retain State accross recomposition and configuration changes?
  • Difference between Stateless and Statefull composeables?

System Design

  • Design Image Loading Library
  • Design Image Downloading Library
  • Design LRU Cache

Common Question

  • String vs StringBuilder

Contributing Guidelines

What interesting questions you had faced while giving interview for Android Engineer role (any level)? Let's open a PR.

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