Easy everything in Mobile Dev, page 3
Map JSON keys to differently named Codable properties
Declare a nested CodingKeys enum mapping userID to the raw value "user_id", or set the decoder's keyDecodingStrategy to convertFromSnakeCase for blanket conversion.
Fetch and decode JSON with async/await and URLSession
Call URLSession.shared.data(from:) inside an async throws function, check the HTTPURLResponse status, then JSONDecoder().decode([User].self) and let errors propagate via try.
Explain UIKit MVC and the Massive View Controller problem
Model holds data, View displays it, Controller mediates between them; the view controller accretes networking, parsing, and logic into a Massive View Controller.
Describe the iOS app lifecycle and SceneDelegate methods
Not running, inactive, active, background, suspended; SceneDelegate handles sceneDidBecomeActive, sceneWillResignActive, sceneDidEnterBackground, sceneWillEnterForeground.
How does Swift's switch differ from C's switch?
Switches must be exhaustive, there is no implicit fallthrough between cases, and cases can match ranges, tuples, and bind values.
Provider package versus raw InheritedWidget
It removes boilerplate, adds lifecycle disposal and scoped reads, and exposes select for granular rebuilds.
Android Becomes an Intelligence System: I/O 2026 Recap
Google’s I/O 2026 Android recap introduced AppFunctions experiments, Gemini Nano 4 previews and tools for hybrid AI. Check each feature’s availability and device requirements before using it in production.
Kotlin 2.4.0 Ships Stable Context Parameters and UUID API
Kotlin 2.4.0 ships stable context parameters, a built-in UUID API, and Java 26 support. Context parameters replace manual dependency threading through call chains.
Android CLI 1.0 Stable Unlocks Headless CI
Android CLI 1.0 went stable at I/O, exposing project scaffolding and device management commands that run without Android Studio. The release finally lets teams script full build pipelines on headless agents and remote dev boxes.
Unify Android EventBus and RxJava with Kotlin Flow
Mixing EventBus, RxJava, and Kotlin Flow in Android codebases creates memory leaks and GC pressure from stream wrapping. Operator translation and lifecycle mismatches drive engineering debt.
I/O 2026 Standardizes AI Server-Driven UI for Android
I/O 2026 made A2UI, Remote Compose, and AppFunctions first-class Android primitives, validating AI server-driven UIs. KMP plus Compose Multiplatform renders cross-platform from one codebase.
isCoreLibraryDesugaringEnabled Nears End of Life
isCoreLibraryDesugaringEnabled and desugar_jdk_libs 2.1.3 are being phased out as Google modularizes Android system updates, ending the j$ namespace workaround for java.time on legacy devices.
Kotlin 2.4.0 Preview, Unified Toolchain, and LSP Alpha Land
Kotlin 2.4.0 stabilizes context parameters and explicit backing fields. A new Kotlin Toolchain unifies build, test, and agent workflows under one command, while the Language Server hits Alpha.
Koog 1.0 Stabilizes Kotlin AI Agent Framework
Koog 1.0 locks APIs for one year in JetBrains' Kotlin AI agent framework, adding local Android LiteRT inference and OpenTelemetry. JVM teams can build production agents without breaking changes. Adopt stable core first, then add beta features as needed.
Kotlin 2.4.0 ships Swift package support and Java 26
Kotlin 2.4.0 adds Swift package dependencies for Native, Java 26 for JVM, and WebAssembly Component Model. Multiplatform teams can consume Swift libraries directly and target newer Java. Upgrade via IntelliJ IDEA, Android Studio, or Gradle.
How would you use Retrofit to GET /posts/{id} and key components?
This checks your understanding of Retrofit's three-layer setup. You need a data class for JSON parsing, an interface with @GET and @Path, and a Retrofit.Builder with baseUrl and a converter.
What is the difference between a started service and a bound service?
Started services run until stopped via startService with no caller interface; bound services expose an IBinder and destroy when all clients unbind.
Explain the difference between Kotlin's let, run, with, apply, and also
Group by this (apply, run, with) vs it (let, also), then by return type.
What do the safe call and Elvis operators do in Kotlin?
?. yields null if receiver is null; ?: provides the right operand when left is null; chain as val len = str?.length ?: 0.
How do you persist a custom Swift struct to JSON in Documents?
Tests fluency with Codable and FileManager sandbox APIs. Good answer: conform to Codable, encode with JSONEncoder, resolve Documents directory via FileManager URLs, write Data atomically, and reverse with JSONDecoder.
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