kotlin - GrindLoop: Android & iOS Interview Prep

Why One-Time Events in Jetpack Compose Keep Breaking

September 30, 2026 by Arsam

Laptop showing a dark-themed code editor on a wooden desk, representing Jetpack Compose development

SharedFlow drops one-time events with no collector, and Channel loses them on cancellation. One login screen built three ways, with Google’s fix: reduce the event to UI state.

Why viewModelScope.launch(SupervisorJob()) Still Crashes Your App

September 29, 2026 by Arsam

Orange balloon drifting away with its string hanging loose, representing a coroutine detached from viewModelScope by launch(SupervisorJob())

Passing SupervisorJob() to launch in viewModelScope doesn’t stop a crash, and it detaches the coroutine from onCleared(). Here’s the two-bug reason, a runnable repro, the fix, and the interview answer.

Why Gson Returns Null Fields Only in Your Release Build

September 28, 2026 by Arsam

Code editor on a dark monitor showing JSON parsing code, illustrating Gson null fields in an Android release build

A Kotlin data class parsed by Gson works in debug and comes back null in release. Here’s the two-bug reason (R8 plus Gson skipping your constructor), the fix, and the interview answer.

Found the Bug in Your Android Debugging Interview and Still Didn’t Pass?

September 28, 2026 by Hass

Laptop showing a code editor next to a mobile emulator, the setup for an Android debugging interview

In an Android debugging interview, the first green test is often only the midpoint. What the bug squash round scores, and the traps that sink candidates who find the bug.

Why Fast Scrolling Duplicates Items in Your Paginated List

September 27, 2026 by Arsam

Close-up of code on a laptop screen, illustrating an Android pagination race condition bug

An Android pagination race condition duplicates list items when two scroll-triggered page loads overlap. Here’s the two-bug reason, the fix, and the interview answer.

Why Your Predictive Back Animation Gets Stuck When the Gesture Is Canceled

September 27, 2026September 25, 2026 by Arsam

Hand holding an Android phone with a blank screen, illustrating a predictive back gesture animation in Jetpack Compose

The predictive back gesture is no longer optional. For apps targeting Android 16 (API level 36), predictive back system animations are enabled by default. Since August 31, 2026, Google Play requires new apps and app updates to target API level 36. So any app still shipping updates is affected. If your app has a custom … Read more

Why One-Time Events in Jetpack Compose Keep Breaking

Why viewModelScope.launch(SupervisorJob()) Still Crashes Your App

Why Gson Returns Null Fields Only in Your Release Build

Found the Bug in Your Android Debugging Interview and Still Didn’t Pass?

Why Your Predictive Back Animation Gets Stuck When the Gesture Is Canceled

Why Your Kotlin Data Class’s equals() Ignores the Parent Class

Why viewModelScope.async Swallows a Failed API Call

The Null Check That Didn’t Save You

What the Algorithm Round Actually Tests in Android Interviews