book

The Ultimate iOS Interview Playbook

by Avi Tsadok

August 2023

Beginner to intermediate

320 pages

7h 42m

English

Packt Publishing

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The Ultimate iOS Interview PlaybookContributorsAbout the authorAbout the reviewer
Who this book is forWhat this book coversTo get the most out of this bookConventions usedGet in touchDownload a free PDF copy of this book
Performing company researchKnowing where you’re going is part of the interviewCompany profiles affect our answersLearning the company characteristicsBuilding the unofficial company profileBuilding our resumeA resume is like a book or a movieStructuring the resume outlineWorking on design and layoutWhat is the personal information part?Formulating the personal summary sectionListing our expertiseSkillsMiscellaneousAvoiding red flagsInviting another set of eyesPreparing for the interviewTaking our timeTechnical, personal, and logistics preparationsSummary
Understanding the hiring processLearning the hiring funnelDistinguishing between different companiesGetting ready for the screening interviewWhat does the screening interview include?Send a thank-you emailAll about the iOS technical interviewWorked-on projectsAnswering Swift and algorithm questionsSolving basic questions about UIKit and SwiftUIMastering development toolsCracking the coding interviewLive coding interviewWorking on a home assessmentPassing the architecture interviewSummary
Understanding the importance of developing a brandLearning what a brand isIncreasing our chances of passing the resume scanningIncreasing our chances of getting an offerExpanding our networkHow to start building your brandContributing to the communityBeing a star in Stack OverflowMaintaining a public GitHub repositoryJoining an open source projectWriting contentBeing expertsImproving wording and expression capabilitiesIncreasing our networkMaking the world aware of our knowledgeCombining all and moreUnderstanding that every in-person interaction is importantSummary
Learning the importance of data structuresIncreasing efficiencyMaking our code modularReusing our codeUsing data structures for an APIAnswering classes and struct questions“What’s the difference between a class and a struct?”“Which is better, a class or a struct?”“Why are structs faster than classes?”Answering questions about Swift array“Please list the Swift array advantages”“How to remove duplicates from an array?”“How do you implement a queue using an array?”“How do you create a new array by mapping the elements of an existing array in Swift?”Covering the Codable protocol“How do you handle optional properties when using the Codable protocol?”“How do you use CodingKeys enumeration to map the keys in a JSON object to the properties of a custom data type?”“How can you convert a formatted date string to a date object in Codable?”Preparing for dictionary- and set-related interview questions“Can you use a dictionary to store configuration data?”“How do you use the filter method to select a subset of key-value pairs from a dictionary based on a condition?”“What is the time complexity of common set operations, such as inserting an element or checking for membership?”“Is it possible to store any type of data in a set collection in Swift?”Summary
How do we master all Swift features?Basic Swift featuresAnswering optionals questionsSolving access-level questionsHandling questions about ClosuresAdvanced Swift language featuresSolving computed and lazy variables questionsSolving extensions questionsSolving generics questionsSolving error-handling questionsSolving protocol questionsSolving memory management questionsSummary
Planning“How do you create a project timeline and plan for the iOS app’s development process?”“How do you estimate development time for a task?”“How do you create a technical design document for an iOS task?”Testing“What is the meaning of unit and integration testing in the context of iOS development?”“How do you perform performance testing in iOS applications?”“Can you explain what it means to write a testable code?”Debugging“Can you explain how to debug memory leaks in iOS applications?”“Can you explain how to debug UI-related issues in iOS applications?”“How do you debug performance issues in iOS applications?”Documentation“Can you explain how you document your iOS code?”“Can you explain how to document design patterns and best practices in iOS development?”“How do you handle the documentation of code that multiple team members are developing?”Summary

Answering questions about Auto Layout“Can you explain what content hugging and compression resistance are in Auto Layout and how they are used to control the layout of UI elements?”“Can you explain how to use size classes in Interface Builder to adapt layouts for different screen sizes and orientations?”“What is the purpose of the safe area in Auto Layout, and how do you ensure that your views are properly positioned within the safe area?”Solving UIView questions“Can you explain how the responder chain works in iOS?”“How can you respond to device orientation changes in UIView?”“Why does UIView not have a ‘viewDidAppear’ method as UIViewController does?”“Can you explain the difference between setNeedsLayout, layoutSubviews, and layoutIfNeeded in UIView? When would you use each of these methods, and how do they impact the layout process?”“What is the difference between the frame and bounds properties?”Understanding everything about UIViewController“Can you list all the life cycle events or methods of a UIViewController, in the order in which they occur?”“Can you explain the concept of UIViewController containment? How would you implement it in your app?”“How do you pass data between view controllers in iOS?”Making sure we are ready with UITableView“How does the queuing mechanism work in a UITableView, and what are some best practices for optimizing its performance?”“What is pagination in UITableView, and how would you implement it to efficiently load and display large amounts of data while maintaining good performance and user experience?”“What are the different approaches for adjusting cell size in a UITableView, and how do you determine the optimal size for cells based on the content they will display?”Performing navigation well“What is the purpose of the navigationItem property in a view controller, and how can you use it to customize the behavior and appearance of a navigation bar in iOS development?”“What are some of the preset options for presenting a UIViewController in iOS, and why is it important to understand these options?”“How would you design a navigation system for an iOS app using the coordinator pattern, where view controllers don’t decide where to go next, and a coordinator object is responsible for managing the navigation flow?”Empowering user experience with animationsGoing over the core concepts of animation in UIKit“How can you create custom transitions between UIViewControllers in an iOS app?”Summary
Entering a new era of developmentUnderstanding declarative programming“What’s the difference between declarative programming and the “classic” programming paradigm, also known as imperative programming?”“How does declarative programming help handle state management in iOS apps?”Learning states and observable objects“Can you explain the differences and use cases for the @State and @Binding property wrappers in SwiftUI?”“What is the purpose of @ObservedObject in SwiftUI, and in what situations would you use it instead of @State or @Binding?”Navigating SwiftUI views“How do you pass data between views using the SwiftUI navigation system?”“Can you explain how to use @Environment(\.presentationMode) to dismiss a presented view in SwiftUI navigation?”Expertise with the SwiftUI life cycle“How does SwiftUI handle state changes during the view life cycle?”“How do you use the onChange modifier in SwiftUI, and what state changes does it respond to?”Expertise in Combine“Can you provide an example of how you would use Combine in an iOS app?”“How do you debug a Combine stream?”Summary
Mastering Core Data questions“How do you design a Core Data Stack that supports concurrency while ensuring thread safety, and how can you use NSManagedObjectIDs in a multi-threaded environment to facilitate this?”“What would your Core Data data model look like for a recipe app that includes ingredients, cooking instructions, and user ratings?”“How would you approach testing Core Data in an iOS app?”Handling persistent state with UserDefaults“Explain how an iOS app and its extensions can share data using UserDefaults. What steps are involved in setting up and using UserDefaults to share data between an app and its extensions?”“Can you explain how to store a struct or a class in UserDefaults in an iOS app?”Storing sensitive information in the Keychain“What is a Keychain Access Group, and how can it be used to securely share Keychain items between different components of an iOS app, such as the app and its extensions?”Working with the filesystem“Can you explain the purpose of each of the following folders in an iOS app: Documents, Library, Cache, and Temp? How would you decide which folder to use for storing different types of files in your app?”Summary
Mastering CocoaPodsLearning how CocoaPods is built“What best practices do you follow when working with CocoaPods, and why are they important?”“What is the difference between pod update and pod install?”Learning about the Swift Package ManagerCreating a Swift packageGoing over the package manifest and foldersSwift package common commandsUsing a Swift package“What are the advantages and disadvantages of using the SPM compared to CocoaPods?”“What are some best practices for organizing and structuring Swift packages to optimize build times and minimize dependency conflicts?”Summary
Building a UI with MVC/MVVMSolving different problems with MVC and MVVMLearning MVCExploring MVVM“How would you implement navigation in an MVVM architecture, considering that the ViewModel should not have knowledge of the View?”“Why is the MVVM architecture considered good for testability in iOS app development?”Decoupling with Dependency InjectionUsing constructor injectionSimplifying things with setter injectionUsing pure functions with method injectionDecoupling our code using protocolsCommunicating using delegation“How does the delegation pattern differ from other communication patterns, such as notifications or closures, in Swift?”Sharing a state using Singleton“How would you avoid using a Singleton in your code? Can you describe some of the alternative approaches you might consider?”“Can you describe the potential issues with using Singletons in a multithreaded environment, and how can these be addressed?”Improving performance with ConcurrencyWorking with GCDCreating advanced queues with OperationQueueBlocking threads with NSLockUsing the Combine Future publisher to implement async operationsGoing over concurrency development best practicesSummary
All about the Separation of Concerns principleDefining the Separation of Concerns principleExplaining the importance of SoCGoing practical with the Separation of Concerns principleDesigning app architectureBreaking the architecture into application layersLearning about data flowDesigning an offline-first system architectureThe architecture design interviewEntering the head of our interviewerApproaching the missionStarting the designCommunicating with the interviewerSummary
Succeeding in live codingLearning about the different live coding testsPreparing ourselves for the coding interviewStarting to codeCoding like a proExcelling in a home assessmentWhat does a home assessment look like?The different skills being tested in a home assessmentGoing over examplesAvoiding red flagsInability to explain or defend a solutionDichotomic thinkingLimited error handlingPoor code qualitySummary
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Content preview from The Ultimate iOS Interview Playbook

4 Data Structures and Algorithms

We spent time and effort on our resume, performing company research and building our developer brand. But what for? To start an interview process at a company we want to work for, and get hired!

So, now that the first step has been achieved, we will turn to our next challenge, passing the iOS technical interview.

The first topic to pass the iOS technical interview will cover data structures such as classes, structs, dictionaries, and arrays. While we could begin with the fundamental principles of the Swift language, that could be considered a more technical subject. In contrast, data structures involve more abstract concepts. Therefore, we will leave the Swift language for Chapter 5.

This chapter will cover the ...