Android interviews reward depth on the platform, not just generic algorithms. Here’s how I’d structure preparation so your time goes to what actually gets tested.

The four rounds you’ll face

Most Android loops include some mix of:

  1. Platform fundamentals — lifecycle, threading, memory, framework internals.
  2. Coding — data structures and algorithms, often Kotlin-friendly.
  3. Mobile system design — design a feed, an offline-first app, an image loader.
  4. Behavioral — collaboration, conflict, ownership, impact.

Allocate study time roughly evenly; candidates often over-index on coding and get caught out by fundamentals and design.

1. Platform fundamentals

Be able to explain, out loud, with examples:

  • Lifecycle — activity/fragment lifecycle, configuration changes, process death.
  • Threading — main thread, Looper/Handler, coroutines, Dispatchers.
  • Memory — leaks, Context choice, the LeakCanary mindset.
  • Jetpack — ViewModel, SavedStateHandle, Flow, Compose recomposition.

A strong signal in interviews is connecting concepts: e.g. explaining why ViewModel survives rotation but not process death, and what to use instead.

2. Coding

Practice in Kotlin so idioms are second nature:

// Example: group anagrams — clean, idiomatic Kotlin
fun groupAnagrams(words: List<String>): List<List<String>> =
    words.groupBy { it.toCharArray().sorted().joinToString("") }
         .values
         .toList()

Focus areas: arrays/strings, hash maps, two pointers, trees, graphs/BFS-DFS, and basic dynamic programming. Aim to talk through trade-offs, not just pass tests.

3. Mobile system design

This is where senior signal shows. Practice designing:

  • An image loading library (caching layers, threading, lifecycle awareness).
  • An offline-first feed (single source of truth, sync, conflict handling).
  • A chat app (real-time transport, pagination, local persistence).

A reusable structure for any prompt:

  1. Clarify requirements and constraints (scale, offline, platforms).
  2. Define the data model and single source of truth (usually the database).
  3. Lay out layers: UI → domain → data → network/cache.
  4. Address threading, error handling, and lifecycle.
  5. Call out testing, observability, and trade-offs.
// Single source of truth: the DB drives the UI; network just updates the DB.
fun observeFeed(): Flow<List<Post>> = postDao.observeAll()

suspend fun refresh() {
    val fresh = api.getFeed()
    postDao.upsertAll(fresh) // UI updates automatically via the Flow above
}

4. Behavioral

Prepare 6–8 concise stories using STAR (Situation, Task, Action, Result). Cover: a hard technical decision, a conflict, a failure you owned, and a project you drove end to end. Quantify impact where you can.

A four-week plan

  • Week 1 — Fundamentals deep dive; write notes in your own words.
  • Week 2 — Coding daily (45–60 min); review patterns, not just problems.
  • Week 3 — System design; do two full mock designs out loud.
  • Week 4 — Behavioral stories + mixed mocks; rest before the loop.

Key takeaways

  • Android interviews test platform depth, not only algorithms.
  • Practice explaining why, not just what.
  • Treat system design as a structured conversation with a clear data model.
  • Have crisp, quantified behavioral stories ready.