Question 1

What is the difference between Flexbox and absolute positioning in mobile layouts, and when would you use each approach?

Accepted Answer

Flexbox and absolute positioning are two fundamental layout approaches in mobile development, and understanding when to use each one is essential for building well-structured user interfaces.

Flexbox is a one-dimensional layout system that distributes space among items in a container along a main axis and a cross axis. It is the default layout model in React Native and is widely used in Flutter through Row and Column widgets. With Flexbox, you define how child elements should grow, shrink, and align relative to one another. For example, if you have a toolbar with a back button on the left a

Question 2

What are the key principles of Material Design, and how do they guide mobile UI development on Android?

Accepted Answer

Material Design is Google's design system that provides a comprehensive set of guidelines for building consistent, intuitive, and visually appealing user interfaces. It was originally introduced in 2014 and has evolved through Material Design 2 and Material Design 3 (also called Material You), which is the current standard for Android development.

The foundational principle of Material Design is the concept of a material metaphor. The system draws inspiration from the physical world, treating UI elements as sheets of material that have surfaces, edges, shadows, and elevation. This means a f

Question 3

What are the fundamental differences between the iOS and Android app structures? How is a native app organized on each platform?

Accepted Answer

iOS and Android have distinctly different app structures, and understanding these differences is important even when using cross-platform frameworks because you will inevitably need to interact with native project configurations.

An iOS app is built around an Xcode project. The central configuration file is Info.plist, which contains metadata like the app's display name, bundle identifier, supported orientations, required device capabilities, and permission usage descriptions. The app's entry point is the AppDelegate, which handles lifecycle events such as app launch, backgrounding, and inc

Question 4

How do permissions work on iOS and Android? What is the difference between install-time and runtime permissions?

Accepted Answer

Permissions are a critical part of mobile development because they control your app's access to sensitive device features and user data. Both iOS and Android implement permission systems, but they work differently in important ways.

On Android, permissions are divided into two categories: normal permissions and dangerous permissions. Normal permissions, like accessing the internet or setting an alarm, are granted automatically at install time because they pose minimal risk to user privacy. These are declared in AndroidManifest.xml and require no user interaction. Dangerous permissions, like

Question 5

How do you make HTTP requests in a mobile application? What are the common methods for consuming a REST API?

Accepted Answer

Making HTTP requests to consume REST APIs is one of the most fundamental tasks in mobile development. Nearly every app needs to communicate with a backend server to fetch data, submit forms, authenticate users, or synchronize content.

In React Native, the most common approach is using the fetch API, which is built into the JavaScript runtime. Fetch is a promise-based API that sends a request and returns a response. A basic GET request looks like fetch('https://api.example.com/users'), which returns a promise that resolves to a Response object. You then call response.json() to parse the JSON

Question 6

What is JSON, and how do you parse and serialize it in mobile applications?

Accepted Answer

JSON, which stands for JavaScript Object Notation, is the standard data interchange format used by most REST APIs. Understanding how to parse JSON responses into usable objects and serialize objects back to JSON for requests is essential for mobile development.

JSON represents data using a simple text format with two primary structures: objects (key-value pairs enclosed in curly braces) and arrays (ordered lists enclosed in square brackets). Values can be strings, numbers, booleans, null, objects, or arrays. A typical API response might look like an object with an id number, a name string,

Question 7

What is the mobile app lifecycle, and what are the main states an app goes through from launch to termination?

Accepted Answer

The mobile app lifecycle describes the sequence of states an app transitions through from the moment it launches to when it is terminated. Understanding these states is essential because they determine when your app can run code, when it should save data, and when the operating system might reclaim its resources.

Both iOS and Android apps share a similar high-level lifecycle with some platform-specific differences. The main states are inactive or not running, active or foreground, background, and suspended or terminated.

When the user taps the app icon, the app launches and moves through

Question 8

What are the common navigation patterns in mobile apps, and when should you use each one?

Accepted Answer

Navigation patterns define how users move between screens in your mobile app. Choosing the right pattern is important because it affects discoverability, usability, and how naturally users can find what they are looking for. There are three primary navigation patterns used in mobile apps.

Stack navigation is the most fundamental pattern. It works like a stack of cards where each new screen is pushed on top of the previous one. Users go back by popping the top screen off the stack, revealing the screen underneath. This is the default navigation pattern for drill-down workflows. For example,

Mobile Developer

Topics

Mobile UI Fundamentals

iOS & Android Platform Basics

Mobile Networking & APIs

App Lifecycle & Navigation

Mock Interview

Quick Stats