Mastering iOS App Development Interviews: Tips for Success
Tags: ios, interview, career, mobile
Published: 2023-09-17 13:42:10

So, you’ve decided to start on the journey of landing your dream iOS app development job. Congratulations!

The world of iOS app development is exciting, ever-evolving, and filled with opportunities. However, competition is fierce, and interviews can be challenging.

In this blog, I’ll share some tips that’ll help you on how to prepare effectively for iOS app development interviews and increase your chances of success.

These tips can be applied to any tech interviews and not use iOS.

I’ll cover key areas including behavior, technical skills, data structures and algorithms (DSA), design patterns, and multi-threading.

## Behavioral Skills: How to Ace the Non-Technical Part
**What to Do:**

**1. Effective Communication:** Be clear and concise when explaining your projects, roles, and responsibilities.

Use the STAR (Situation, Task, Action, Result) method for behavioral questions.

**Example:**

**Situation:** “In my previous position, our team was struggling to meet project deadlines due to a lack of effective communication.”

**Task:** “I was assigned the task of improving team communication and ensuring that everyone was aligned on project goals.”

**Action:** “I initiated daily stand-up meetings to keep everyone updated on their tasks and progress. Additionally, I set up a shared project management tool to track tasks and deadlines, improving transparency.”

**Result:** “As a result of these efforts, our team started meeting deadlines consistently, and our project completion rate increased by 30%.”

**2. Problem-Solving Attitude:** Highlight situations where you faced challenges, how you approached them, and the results achieved. Show them that you have the ability to adapt and learn.

**Example:** “I encountered a critical bug just before a product release. I quickly identified the issue, coordinated with the QA team, and we fixed it within hours, ensuring an on-time launch.”
What Not to Do:

**1. Being Overly Technical:** As developers we like to be super technical, but avoid diving into technical jargon when answering behavioral questions. Keep it simple and focused on your actions and outcomes.

**2. Blaming Others:** Never blame teammates or colleagues for project failures or challenges. Instead, discuss your role in resolving issues. You must sound like a problem solver not a finger pointer.

**3. Don’t Overshare:** While discussing personal experiences, avoid sharing too much information unrelated to the job or going off-topic.

##Technical Skills: The Code Challenges
**What to Do:**

**1. Solid Foundation:** Brush up on core concepts like Swift, UIKit, Auto Layout, and memory management. Be prepared to explain your projects in detail.

**Example:** “In my last project, I used Auto Layout constraints to create a responsive user interface that worked seamlessly on both iPhone and iPad.”

**2. Practice LeetCode and HackerRank:** Solve iOS-specific coding problems regularly. Understand the time and space complexity of your solutions.

**What Not to Do:**

**1. Guessing Answers:** If you don’t know the answer, don’t guess. Instead, explain how you would approach the problem or ask for a hint, be completely honest that you don’t know the answer but are open to discuss the approach for the same.

**2. Ignoring Edge Cases:** Be thorough in your code. Consider edge cases, handle errors gracefully, and write tests when possible, a code without test case is like a car without an engine.

**3. Avoid Code Dumping:** Explain your thought process while solving coding problems; don’t just dump code on the screen without any explanation.

##Data Structures and Algorithms (DSA): Mastering the Core
**What to Do:**

**1. DSA Basics:** Review common data structures (arrays, linked lists) and algorithms (sorting, searching). Understand their use in iOS development.

**Example:** “I used a binary search algorithm to optimize a large dataset search in my app.”

**2. Optimize Code:** During coding interviews, focus on efficient algorithms and maintainable code.

**3. Big O Notation:** Understand and use Big O notation to describe algorithm efficiency. Explain why one algorithm is better than another.

**Example:** “The Merge Sort algorithm has a time complexity of O(n*log(n)), making it more efficient than Bubble Sort with O(n²) complexity.”

**What Not to Do:**

**1. Ignoring Time Complexity:** Don’t overlook the importance of algorithm efficiency. Explain your thought process clearly.

**2. Over-Optimizing:** Don’t prematurely optimize code unless necessary. First, ensure it works correctly, then optimize if needed.

**3. Memorizing DSA solutions:** Avoid memorizing DSA solutions as interviewers may present modified versions of problems where the memorized solution may not apply. Instead, focus on understanding core concepts and problem-solving techniques to adapt to varying scenarios effectively.

## Design Patterns: Building Robust iOS Apps
**What to Do:**

**1. Know Common Patterns:** Study design patterns like Factory, Adapter, Singleton, and Delegate. Understand when and why to use them.

**Example:** “In my last project, I employed a pattern to separate business logic from the UI, leading to easier maintenance.”

**2. Adaptability:** Explain how you chose design patterns based on the specific needs of your projects. Show that you can adapt patterns to suit different scenarios.

**Example:** “For our e-commerce app, we used the Strategy pattern to dynamically change payment gateways based on user preferences, providing a seamless shopping experience.”

**3. Real-world Usage:** Discuss how you applied design patterns in your projects. Explain the benefits they brought and the problem they solved.

**4. Encourage Code Reusability:** Show how you’ve used design patterns to promote code reusability and maintainability. Share examples of how you’ve designed modular components that can be easily reused across different parts of your app.

**What Not to Do:**

**1. Forcing Patterns:** Don’t force-fit a design pattern if it doesn’t naturally fit the problem at hand. Always consider whether it’s appropriate for the specific use case.

**2. Memorizing Code:** Don’t memorize design pattern implementations; understand their concepts and adapt them as needed.

## Architecture Practices: Having a SOLID foundation
**What to Do:**

**1. Modularize Code:** Explain how you’ve modularized your codebase to isolate and encapsulate functionality based on volatility. Showcase your ability to create independent modules that can be easily tested and reused.

**Example:** “In our project, we structured the code into modules for authentication, networking, and UI components, facilitating code maintenance and testing.”

**Note:** The highlighted point here is based on volatility which itself is a huge topic and out of the scope of this blog.

**2. Follow SOLID Principles:** Demonstrate your adherence to SOLID principles (Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, Dependency Inversion) when designing classes and components. Show how this improves code flexibility and maintainability.

**Example:** “We applied the Single Responsibility Principle by breaking down our classes into smaller, focused components, making it easier to extend and modify.”

**3. Dependency Injection:** Discuss how you’ve employed dependency injection to enhance code testability and reduce tight coupling between components.

**Example:** “We used dependency injection to provide dependencies to classes, facilitating unit testing and enabling easy swapping of implementations.”

**What Not to Do:**

**1. Don’t Over-complicate Architecture:** Avoid over-engineering your architecture with unnecessary abstractions or patterns that add complexity without clear benefits. Keep your architecture balanced and pragmatic.

**2. Avoid Tight Coupling:** Be cautious of tightly coupled components that hinder code flexibility. Show that you understand the importance of loose coupling and how to achieve it in your architecture.

**3. Don’t run behind the next shining thing:** Resist the urge to hastily adopt new architectures or design patterns without conducting a thorough analysis.

It’s important to avoid situations where, after several development cycles, it becomes evident that the chosen approach has unnecessarily complicated a simple straightforward task.

## Multithreading: Ensuring Smooth App Performance
**What to Do:**

**1. GCD and OperationQueue:** Understand Grand Central Dispatch (GCD) and OperationQueue for multithreading. Explain their differences and use cases.

**Example:** “I used GCD to fetch data asynchronously and update the UI without freezing the app.”

**2. Thread Safety:** Discuss how you handled multithreading challenges, such as avoiding race conditions and deadlock.

**3. Resource Management:** Demonstrate how you effectively managed finite resources, such as network connections or database access, using multi-threading and concurrency to prevent bottlenecks and improve app performance.

**Example:** “In a social media app, I implemented connection pooling and ensured that network requests were handled on a background thread, preventing UI freezes during data retrieval.”

**4. Asynchronous Programming:** Showcase your proficiency in asynchronous programming using closures, completion handlers, or async/await in Swift. Explain how you handle background tasks without blocking the main thread.

**Example:** “I utilized async/await to simplify complex asynchronous operations, making code more readable and maintainable while ensuring smooth user interactions.”

**What Not to Do:**

**1. Ignoring Thread Safety:** Never neglect thread safety in your code. Discuss how you ensured data integrity and UI responsiveness.

**2. Complex Solutions:** Don’t over-complicate multi-threading. Use the simplest approach that meets your app’s requirements.

**3. Ignoring Deadlocks:** Don’t ignore potential deadlock scenarios where threads are waiting indefinitely for each other. Always implement deadlock prevention strategies.

## Conclusion

Preparing for iOS app development interviews requires a balanced focus on both technical and behavioral aspects. Remember to communicate effectively, showcase your technical skills, demonstrate your DSA knowledge, apply design patterns judiciously, and master multithreading concepts.

By following these do’s and avoiding the don’ts, you’ll be well-prepared to tackle iOS app development interviews with confidence. Good luck on your journey to landing that dream job in iOS development!