8 iOS interview questions (including their sample answers)

Updated 1 June 2023

An operating system manages a device's hardware and software needs, including tasks such as input and output management, filing, memory and process management and peripheral device control. Several operating systems are available depending on your device, including iOS. Familiarising yourself with the questions interviewers may ask in an IOS interview can guide you on the specific aspects to focus on in your research to ensure favourable outcomes. In this article, we discuss eight iOS interview questions and provide sample answers to help you prepare.

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8 iOS interview questions with sample answers

Analyse the following iOS interview questions that hiring managers may ask and some sample answers:

1. Kindly describe the types of iOS application states.

Recruiters can use this question to assess your understanding of the iOS application lifecycle. They can also use it to evaluate your knowledge of developing practical and responsive applications capable of handling background tasks. It can also help them assess your ability to manage state transitions to provide a smooth user experience efficiently. Consider defining application states and their importance. State the various iOS application states and briefly explain their significance in managing user experience.

Example: 'Application state refers to the various stages the app goes through during user interaction and task execution. The not running state is where the app isn't executing any code as the user hasn't launched it. The active state is where the app receives user interactions in the foreground. Inactive is where the app is in the foreground but not receiving user interactions. Background state occurs when the user switches to another application leaving an active one in the background. In the suspended state, the app is in the background but not executing any task.'

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2. Kindly differentiate between the app and bundle ID.

Interviewers can use this question to assess your knowledge in identifying and differentiating between iOS apps. It can help them evaluate your capabilities of effectively packaging and distributing apps on distribution channels like the app store. Consider describing an application and how it works. You can define app and bundle IDs and explain their importance in the smooth operation of an app. Providing a practical example of how you can use the app and bundle IDs when operating apps can give the hiring manager an idea of your skills in managing iOS tech stacks.

Example: 'An application typically uses binary code including the actual code, resources and assets that support its functionality. A bundle ID is an identification string unique to each app in the system. You can use this ID to differentiate between apps, especially those created by the same developer. The bundle ID is in reverse DNS format. In contrast, an app ID connects the application and its provisioning profile. You can use the app ID to provide restrictions on applications that users can and can't use to help them tightly regulate app usage.'

3. How does iBeacon work and what's its importance?

Recruiters can use this question to assess your understanding of the available iOS frameworks and technologies. They can also use it to evaluate your Bluetooth Low Energy (BLE) knowledge in signal transmission. Mentioning the practical applications of BLE can highlight your understanding of its relevance in various aspects, such as location-based services. You can give examples of how you used iBeacon in your previous roles to improve user experience, enhance customer engagement and increase business opportunities.

Example: 'iBeacon is an iOS technology that promotes location-based services using BLE. It uses a transmitter-receiver model where a small hardware beacon transmits Bluetooth7 signals regularly. The iOS device with beacon support acts as the receiver allowing it to receive signals from the beacon when within a specific proximity. You can apply the proximity-based interaction features of iBeacons in various industries such as retail and marketing, advertisement, healthcare, navigation and tourism. In large malls of event venues, you can set up beacons at specific locations, allowing users to receive direction signals on their iOS devices.'

4. Tell us about implementing the Model View Controller (MVC) in IOS.

Interviewers can ask you this question to determine your understanding of the different design architectural practices you can use in iOS development. It can also help them assess your ability to divide application components and organise code to separate data, user interface and business logic. You can begin by explaining the MVC pattern and its benefits. You can also discuss the available MVC variations and how to use them.

Example: 'In MVC, model, view and controller represent different aspects of the implementation pattern. The model represents the app's business logic and data, including data structures and algorithms. It also describes their interaction with external databases. View represents the user interface, including the display buttons and labels that represent the model. You can use UI frameworks such as SWIFT to implement views. Controller mediates between views and model by processing user inputs and updating the model.'

5. Describe the UI elements present in IOS.

Hiring managers can use this question to assess your understanding of the available user interface elements and how you can use them to provide a satisfactory user experience. It can give them an idea of your skills in creating an interactive and captivating user interface to promote user engagement. Describe the various user interface frameworks you can use. Discussing your steps to customise applications to match branding and user needs can demonstrate your commitment to brand promotion and customer satisfaction.

Example: 'Examples of the UI elements available for iOS can include labels, buttons, text fields, navigation bars, alerts sheets, tables, collections and image views. You can use labels to display texts with custom fonts and colours. Buttons enable user interactions with the application and come in various forms, such as image-based or custom buttons. Text fields enable user responses by providing a space to input text or numbers. You can use table views to provide an organised system for viewing data entries or settings. Navigation bars enable users to move to different applications' views or sections.'

6. Name some programming languages you can use in iOS development.

Recruiters can use this question to determine your programming proficiency, which they can use to assess your ability to develop, manage updates or repair iOS bugs. They can also use this question to determine your understanding of the iOS-specific languages and your experience using them. Provide a list of the platform's particular languages you know and mention their characteristic features. You can also describe specific tasks or scenarios that require a particular language.

Example: 'Just like other operating systems, you require proficiency in programming to develop, maintain and repair iOS. Examples of common iOS-specific languages include Swift and Objective-C. Initially, iOS programmers used Objective-C for system development but now commonly use Swift as it offers better performance benefits. Swift is an open-source and intuitive programming language. It offers features such as Automatic Reference Counting (ARC), tuples and multiple return values, generics, functional programming patterns and powerful error handling. It uses Low-Level Virtual Machine (LLVM) as its compiler framework, which translates assembly language to machine code, offering faster processing.'

7. Kindly describe how the duties of an iOS developer differ from other OS developers.

An interviewer can use this question to assess your understanding of the role. Reviewing the job description to identify what they're looking for in a new hire can help you provide a relevant answer. Mentioning duties specific to iOS and not other operating systems can give you a competitive advantage over other candidates.

Example: 'Although the roles of software developers have some commonalities, they may differ in terms of the programming languages, device and fragmentation considerations and operation of platform-specific APIs and Software Development Kits (SDKs). iOS developers use programming languages such as Swift and Objective-C, which are platform-specific for iOS. They can use these languages in iOS design, maintenance and development. This role involves writing code, testing it and repairing bugs to ensure smooth app functioning. iOS developers also use Xcode, which offers tools and debugging capabilities specific to iOS.'

8. Which JSON framework does iOS support?

A hiring manager can use this question to evaluate your technical understanding of integrating iOS applications with web services that utilise JSON Application Program Interfaces (APIs). They can also use it to determine your knowledge of the various JSON framework compatibility and performance options available and your ability to select an appropriate one for the project. You can begin by defining the JSON framework. Consider providing a list of the industry's common frameworks and briefly explaining their unique characteristics. You can also explain the frameworks that suit specific projects to impress the hiring committee.

Example: 'Examples of some JSON frameworks that iOS supports include SBJson, Django and UCJson. SBJson is a chunk-based framework that implements a JSON parser and operator in objective-C. Its JSON parsing feature allows users to convert data into objective-C objects such as arrays and dictionaries for easier handling. It also provides several parsing behaviour options to create custom parsing logic.'