Interview guides / android

Crashy item list: Android Interview Question

Crashy item list interview question with a clear example answer for Android engineers. Practice with AceMobileInterview.

This is a common Android interview topic: Crashy item list.

Below is a concise answer you can adapt in a real interview, then go deeper in the full AceMobileInterview track.

1. 1.Swipe-delete or empty list can crash detail navigation. Fix unsafe indexes/nulls (≈30–45 min).

   ## Scenario List/detail crashes after delete and when empty. ## How to investigate - Exception breakpoint / Logcat stack - Delete last item; tap quickly during animation - Find `list[index]` and `!!` ## Planted bug 1: Stale index click **Symptom:** `IndexOutOfBoundsException` **Root cause:** Click listener captures index; list mutates before navigation **Fix:** Pass item `id`; look up in the current snapshot ## Planted bug 2: Unsafe `!!` on args **Symptom:** NPE when args missing **Root cause:** `requireArguments().getString("id")!!` **Fix:** Null-check; pop back; show empty state ## Planted bug 3: Empty list assumption **Symptom:** Crash in header/binder **Root cause:** Code assumes `items.first()` **Fix:** Guard empty; proper empty UI ## Optimization tips - Prefer immutable list snapshots in UI state - Key LazyColumn items by id ## What to say in the interview - How the stack pointed to the listener capture - Regression cases you’d add