iOS Interview Questions and Answers 2017 - Swift - Series Overview

TL;DR

This video provides an overview of common topics and tips for iOS developer job interviews, including automatic reference counting, communication patterns between views, view lifecycle, favorite Apple frameworks, testing, third-party libraries, coding exercises, and take-home projects.

Transcript

what's up guys I'm Sean and I'm an iOS developer here in San Francisco I just recently left my first developer job and now I'm in the market for my second one it's not the end of April in 2017 and I've made the rounds all over town large companies small companies all in all I've done about 15 to 20 interviews that made it to the phone screen or lat... Read More

Key Insights

• 👥 Key Insight: The speaker has gone through 15 to 20 interviews for iOS developer roles in San Francisco, giving them insights into the most common interview topics and questions.
• 📱 Key Insight: One common topic in interviews is automatic reference counting (ARC) and understanding memory leaks, retain cycles, and how to fix them by using weak references.
• 🔀 Key Insight: Another common topic is communication patterns between views, specifically delegates versus observers and notifications. It is important to know when to use each pattern and their pros and cons.
• 🖥️ Key Insight: Knowledge of the view lifecycle in iOS, including viewdidload, viewwillappear, and other methods, is often tested in interviews.
• 🍎 Key Insight: Many interviewers will ask about the interviewee's favorite Apple framework to work with, expecting specific reasons as to why they like a certain API.
• 🏗️ Key Insight: Understanding the differences between classes and structs, including reference types versus value types and inheritance, is important for interviews.
• 🔍 Key Insight: Interviewers may inquire about filter, map, and reduce, as well as testing and the use of third-party libraries.
• 🔢 Key Insight: Coding exercises commonly involve topics such as gesture recognizers, networking, debugging, breaking down units, and iterative loops.
• 🏡 Key Insight: Take-home projects are a common part of the interview process, giving candidates the opportunity to showcase their skills and learn in a less pressured environment.

Questions & Answers

Q: What are some common topics and tips for iOS developer job interviews?

Common topics for iOS developer job interviews include automatic reference counting, communication patterns between views, the view lifecycle, favorite Apple frameworks, testing, third-party libraries, and coding exercises. Tips for these topics include understanding automatic reference counting and fixing retain cycles, knowing when to use delegates versus observers, learning about the view lifecycle methods, exploring third-party libraries' pros and cons, understanding filter-map-reduce functions, and practicing gesture recognizer and networking exercises. It is also important to be prepared for take-home projects and debugging questions.

Q: How does automatic reference counting work in iOS development?

Automatic reference counting (ARC) is a memory management technique in iOS that keeps track of strong references to objects. When the count of strong references to an object reaches zero, ARC automatically deallocates it from memory. However, if there is a retain cycle, where two objects have strong references to each other, the count will never reach zero, resulting in a memory leak. To fix this, you can make one of the strong references a weak reference. For a deep understanding of ARC, Apple provides extensive documentation on the topic.

Q: What are delegates and observers in communication patterns between views in Swift?

Delegates and observers are two communication patterns used between views in Swift. Delegates enable one-to-one communication, where one view communicates with another view through a delegate protocol and methods. Observers, on the other hand, allow one-to-many communication, where one observer receives notifications from multiple areas in the code. Delegates are great for specific, targeted interactions, while observers are suitable for broadcasting events to multiple listeners. It is important to understand the pros and cons of each pattern and know when to use them in different situations.

Q: What is the view lifecycle in iOS development?

The view lifecycle refers to the sequence of methods called during the creation and destruction of a view in iOS development. The main methods in the view lifecycle include viewDidLoad (called once when the view is loaded into memory), viewWillAppear (called every time the view appears on the screen), viewWillDisappear (called before the view disappears), viewDidLayoutSubviews (called when the view has laid out its subviews), and viewDidAppear (called when the view has completely appeared on the screen). It is crucial to know the purpose and order of these methods to effectively manage the view's behavior and UI updates.

Q: Why is testing important in iOS development job interviews?

Testing is an important aspect of iOS development, and it is frequently asked about in job interviews. Interviewers want to determine if a candidate has experience and understanding of how to write tests for their code. Testing ensures the reliability, quality, and correctness of the code and helps catch bugs and issues before they reach the production environment. It is recommended to focus on learning how to build testing suites and practicing testing in your iOS projects to demonstrate your competencies in this area.

Summary & Key Takeaways

• The iOS developer discusses his experience with 15 to 20 job interviews for his second developer job, covering various stages like recruiter calls, phone screens, and on-site interviews.

• He highlights key topics that were frequently asked during the interviews, including automatic reference counting, communication patterns between views, view lifecycle, favorite Apple frameworks, testing, third-party libraries, and coding exercises.

• The iOS developer emphasizes the importance of being prepared for these topics and shares valuable tips and insights for each of them.