Intermediate interview questions in Android & Kotlin, page 6
Difference between @Path and @Query in Retrofit with example URLs
Tests Retrofit URL construction. @Path fills a path template like /users/{user}/repos with "octocat" to make /users/octocat/repos. @Query appends ?q=retrofit to /search/repos. Red flag: claiming @Query changes the path.
OneTimeWorkRequest vs PeriodicWorkRequest and minimum repeat interval
Tests WorkManager scheduling constraints and battery tradeoffs. Contrast one-shot chaining with non-chained periodic work, cite the 15-minute minimum, and tie it to system batching under Doze and App Standby. Red flag: claiming exact intervals or no minimum.
Chain WorkManager tasks and pass a file URI between workers.
This tests WorkManager chaining and data passing. A strong answer chains Download, Unzip, and Process with WorkContinuation, passes URI via outputData, and reads it with inputData. A red flag is suggesting global state, SharedPreferences, or thread blocking.
Roles of minifyEnabled and shrinkResources and common pitfalls
Tests R8 code shrinking vs resource stripping and runtime risks. Outline: minifyEnabled shrinks code; shrinkResources removes unused assets and requires minifyEnabled; dynamic access like getIdentifier() crashes; keep resources with tools:keep or keep.xml.
Create a custom View from scratch that draws a shape
This tests Android View measurement and drawing contracts. A strong answer covers: onMeasure resolves dimensions against parent MeasureSpec; onDraw renders with Canvas and Paint; constructors parse attributes.
How do you implement OAuth2 token refresh with Retrofit Authenticator?
Implement authenticate() with a blocking refresh, new Request with new token, Mutex for parallel 401s.
How would you implement a constrained photo upload with WorkManager?
Tests knowledge of WorkManager constraints and retry policies for deferrable background uploads. A strong answer names OneTimeWorkRequest with Constraints for charging and unmetered network, plus BackoffPolicy for retry.
Architect periodic and on-demand sync with WorkManager
Tests combining periodic and push WorkManager requests safely. Outline: one Worker class, PeriodicWorkRequest hourly and OneTimeWorkRequest on push, with ExistingWorkPolicy.KEEP plus constraints. Red flag: two Workers, no deduplication, or ForegroundService.
How does WorkManager guarantee task execution across reboots and process death?
Tests your understanding of WorkManager's durability under process death. Strong answer: Room database persists requests; JobScheduler or AlarmManager executes them; BroadcastReceiver reschedules on reboot.
Build a custom layout in Jetpack Compose
Use the Layout composable with a MeasurePolicy, measure each child once with constraints, then place children and report your size.
R8 shrinking, obfuscation, and optimization
Shrinking removes unused code/resources, obfuscation renames symbols to short opaque names, optimization inlines and simplifies; shrinking also strips unreachable code that could be exploited.
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