It is used when we need to invoke our methods like the object method. A category is a way to add additional methods to a class without extending it. It is used to add a collection of related methods and additional methods to built-in classes in the Cocoa Frameworks. A senior iOS developer interview usually focuses on project basics and things you have learned. All potential application edge cases should be well known to the interviewee, including application scaling, vulnerabilities, and making things modular in an application.

ios developer interview questions

An app enters the background state briefly on its way to being suspended. The reuseIdentifier is used to group together similar rows in a UITableView, i.e., the rows that differ only in their content, otherwise having similar layouts. A deadlock is a situation that occurs when at least two threads are locked on a different resource, and both are waiting for the other resource to finish its job.

Top Answers to iOS Interview Questions

The Liskov Substitution Principle (LSP) states that objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program. This principle is often referred to as design by contract or, as of late in the Swift community, referred to as protocol-oriented programming. This is conceptually the same thing in Swift as it is in Objective-C. It deallocates memory used by objects whose reference count dropped to zero.

ios developer interview questions

This will require you to use garbage collector functions to free memory. For example, you must use the NSMutableArray type to be able to resize the array. Objective-C uses dynamic typing, which performs type checking at runtime. This means that the code can compile even if it contains errors that prevent the script from working properly.

Best Emotional Intelligence (EQ) Interview Questions to Help You Evaluate a Job Candidates

Senior developers are expected to be able to ship full iOS products from start to finish, after all. But in large companies with big iOS development teams (think 25+ people) specialization and focus on a deep knowledge of a specific problem such as networking also occurs though. This is by no means an exhaustive list, but it can help you prepare for your upcoming technical iOS interview. Swift is an object-oriented programming language that requires fewer lines of code than typical applications written with either Objective-C or Java; this makes writing iOS apps much quicker. Apps also run on a more secure system because no runtime errors are possible when developers write error-free codes while coding using the Swift compiler toolkit.

ios developer interview questions

This restriction applies in particular to classes derived from UIResponder or that require modifying the user interface of your app in some way. BrainStation’s iOS Developer career guide is intended to help you take the first steps toward a lucrative career in iOS development. Read on for some common iOS Developer job interview questions, as well as strategies on how to answer them. Developed by Apple Inc., Swift is an intuitive programming language that lets iOS developers build applications for Apple TVs, iPhones, iPads, iPods, Apple Watches, and Macbooks.

Mid iOS Developer Interview Questions

By assigning a QoS, you’re telling the system how important it is, and the system prioritizes and schedules it accordingly. SpriteKit, SceneKit, and Metal are expected to boost a new generation of mobile games that push the boundaries of what the powerful GPUs in iOS devices can do. After each project, we’ll show you what kinds of interview problems you’ll now be able to solve using the techniques you just applied. Practicing for interviews takes tons of time and patience, and there is no golden ticket to cracking the coding interview.

It is a list comma-separated type and is enclosed in parentheses. Both of these methods are present in AppDelegate.swift file and are used to add functionality to the App when the App is going to be launched. Completion handlers are functions used as parameters to pass to another function. They are primarily tasked with handling asynchronous event responses. In addition, completion handlers provide applications with information about an operation’s completion. JSON was initially developed as a page scripting language for the Netscape Navigator Web browser and was based on JavaScript.

What is the difference between atomic and nonatomic properties? Which is the default for synthesized properties?

Finally, this question may be used to gauge the developer’s motivation and interest in iOS development. Code review is a similar process of collaboration and knowledge transfer, but unlike pair programming, it doesn’t happen at the same time, and therefore it is asynchronous. With code review, after a developer writes a piece of code or a feature, someone else on the team has a look at it. The reviewer checks if the code makes sense and suggests changes and refactorings to be done to improve it. That opens up an online or offline discussion about the code, which is great.

In essence, it aids in concurrent code execution by delegating thread pool management from the developer to the OS. We can apply more rules for our use cases, particularly those dealing with character groups, string positions, etc. In practice, in all computer languages, the REGEX syntax is the same. The application is getting events while it is active in the foreground.

Swift provides modern capabilities that developers enjoy while being inherently safe by design. You may also already realize several reasons to choose iOS development. Android is less standardized than iOS and has more types of devices, which means you need more time and money to do the designing, but apps designed for it have better UI/UX. The user defaults system, which we programmatically access through the NSUserDefaults class, uses property lists to store objects representing user preferences.

ios developer interview questions

With this question, your interviewer is assessing your knowledge of different messaging patterns used in iOS. All of those happen to be the majority of customer facing applications iOS developers build. At Full Scale, we have a pool of talented and experienced iOS developers. Our recruitment and assessment program ensures that we only hire the most skilled and qualified developers. This is to ensure that we provide our clients with the best software services.

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