Easy interview questions in Mobile Dev, page 5
How do you arrange UI elements in Jetpack Compose?
Tests your grasp of Compose's declarative layout model. Explain Row (horizontal) and Column (vertical) as the core layout composables. Define Modifier as the standard way to configure size, spacing, and behavior.
How to arrange UI elements in Jetpack Compose?
This tests your grasp of Compose's declarative layout basics. A good answer defines Column (vertical) and Row (horizontal) for structure, and Modifier for decoration, size, and behavior. A red flag is confusing Modifiers with simple styling.
Axios advantages over fetch
Axios auto-parses JSON, rejects on HTTP error status, and offers interceptors, timeouts, and cancellation out of the box.
When is UserDefaults right, what are its limits, and native types?
Tests if you treat UserDefaults as a small preference store, not a database. Good answers name native plist types, cite no encryption and small size limits, and name Core Data or Keychain for heavy or sensitive data. Red flag: storing images or passwords.
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.
How do you pass data with Navigator.push and return data with Navigator.pop?
Tests imperative navigation and async result patterns. Strong answer: push via MaterialPageRoute with constructor args; await the Future from Navigator.push; pop with Navigator.pop(context, result). Red flag: using global state instead of the Future result.
Navigator.push vs Navigator.pushNamed in Flutter
Tests Flutter navigation patterns and scalability. A strong answer contrasts inline widget construction with centralized route tables, noting pushNamed centralizes routes but complicates type-safe data. Red flag: named routes are always better for large apps.
What is a ViewModel and what lifecycle problem does it solve?
Tests config-change survival: ViewModel outlives Activity recreation so state survives rotation. Strong answer notes it holds non-serializable data and separates concerns, but does not survive process death.
What is a Jetpack ViewModel and the problem it solves?
This tests your understanding of lifecycle-aware state preservation. A good answer explains that ViewModels survive configuration changes (like rotation) to hold UI data, separating it from the transient UI controller.
What problem does Jetpack ViewModel solve during configuration changes?
This tests your understanding of state loss during configuration changes. A good answer explains that Activities are destroyed on rotation, and ViewModel survives this event, preserving UI state.
Explain the roles of ViewModel, Repository, and data source in MVVM
Tests your grasp of unidirectional data flow and separation of concerns in Android MVVM. A strong answer maps ViewModel to UI state, Repository to data coordination, and Room or Retrofit to I/O.
Explain ViewModel, Repository, and Data Source in MVVM
This tests your understanding of separation of concerns. A great answer defines ViewModel (UI state), Repository (data abstraction), and Data Sources (implementation), then explains the unidirectional data flow.
Explain ViewModel, Repository, and Data Source in MVVM
This tests your grasp of separation of concerns in Android. A good answer defines ViewModel, Repository, and Data Source roles, then traces the unidirectional data flow. A red flag is having the ViewModel directly access a data source like Retrofit.
Platform-specific file extensions
Name files Component.ios.js and Component.android.js; import without the extension and the bundler picks the right one per platform.
How do you pass data between Fragments with Jetpack Navigation?
Define args in nav graph XML, navigate with generated Directions, read with navArgs() in target Fragment.
How do you pass data between Fragments with Jetpack Navigation?
Tests knowledge of modern, type-safe argument passing. A good answer defines the argument in the nav graph XML, uses the Safe Args plugin to generate Directions/Args classes, navigates with the action, and retrieves the data in the destination via `by…
How to pass data between Fragments with Jetpack Navigation?
This tests your knowledge of type-safe argument passing in Jetpack Navigation. A good answer defines the argument in XML, uses the Safe Args plugin to generate code, passes data via the Directions class, and retrieves it with the Args class.
Cross-platform shadow with Platform API
IOS uses shadowColor/Offset/Opacity/Radius, Android uses elevation; merge both via Platform.select inside a style.
Explain ephemeral vs app state and when to use setState
This tests state scoping judgment. Ephemeral state is local to one widget, like a page index or checkbox value, and setState fits perfectly. App state is shared, like a user profile or cart, and needs a state management solution.
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.
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