iOSInterviewQuestions: Answered iOS Interview Questions for Objective-C and Swift

What the Repository Covers and Who It Is For

iOS technical interviews often probe candidates on topics specific to the platform: memory management under ARC and MRC, Objective-C runtime introspection, the responder chain, RunLoop behavior, threading with GCD and NSOperation, and UIKit layout internals. These topics are not covered well by general programming interview resources.

iOSInterviewQuestions gathers these iOS-specific questions and, importantly, provides reference answers. The repository is aimed at experienced iOS developers preparing for mid-level to senior positions who want to review their knowledge of the platform internals rather than algorithm problems.

The primary content is in Chinese (Simplified), though the project structure and file names use English. The README notes that the project was originally created by 微博@iOS程序犭袁 (ChenYilong) and is associated with the WeChat public account iTeaTime (技术清谈). The Q&A format is structured as written answers, not code challenges, though the repository also includes programming challenges as separate materials.

Repository Structure and How to Use It

The repository is organized into several directories, each covering a different dimension of iOS interview preparation.

The main Objective-C section is in `01《招聘一个靠谱的iOS》面试题参考答案/`. This contains two documents covering 55 questions drawn from a 2015 blog post titled "Hiring a Reliable iOS Developer" by Weibo user @sunnyxx. The questions are split into Part 1 (上) and Part 2 (下), and each has a detailed reference answer.

The Swift section is in `02_Swift_interview_questions/` and contains two documents: `theory.md` covering Swift language foundations and Objective-C language basics, and `practical.md` covering iOS project development skills. These target a reader who knows iOS development and is preparing for questions about Swift-specific behavior.

The `Behavioral_based_interviewing_Competency_Based/` directory holds three documents: self-introduction templates (`objective_qa.md`), subjective question responses (`subjective_qa.md`), and software engineering behavioral questions (`technical_qa.md`). The `Other/` directory includes a software development terminology reference.

Programming challenges are in the `Swift/` and `SwiftUI/` directories, with MVVMDemo and SwiftUIDemo as worked examples. A technical design document template is available in `Other/TechnicalDesignDocumentDemo`. These give candidates a concrete starting point for the practical parts of an interview.

The Objective-C Section: 55 Questions in Detail

The Objective-C section is the most developed part of the repository. The 55 questions come from a well-known Chinese blog post that was widely circulated in the iOS developer community. The first question in the set is a code-correction problem; the remaining 54 are short-answer questions.

Topics in the Objective-C section cover areas that are specific to iOS and macOS development: the difference between `@property` attributes like `assign`, `retain`, `copy`, and `weak`; the behavior of categories and extensions; method swizzling via the Objective-C runtime; memory management patterns under different ownership models; and threading safety guarantees in different contexts.

These questions are relevant to candidates interviewing for positions that maintain Objective-C codebases, which remain common in large consumer apps that predate the Swift transition. They are also relevant for understanding how Swift interoperates with the Objective-C runtime, since many Swift features (including `@objc` attributes, dynamic dispatch, and protocol extensions) have behavior that makes more sense with an understanding of the underlying runtime model.

Limitations and What the Repository Does Not Cover

iOSInterviewQuestions is a study reference, not an interactive learning tool. There is no code execution environment, no answer-checking mechanism, and no difficulty scoring. The reader must evaluate their own answers against the reference answers in the documents.

The repository does not cover SwiftUI in depth. The SwiftUI demo in `SwiftUI/` is a programming example rather than a set of interview questions. Teams hiring for SwiftUI-heavy positions will need to source those questions elsewhere.

For algorithm and data structure preparation (array sorting, graph traversal, dynamic programming), iOSInterviewQuestions provides nothing. LeetCode is the widely-used alternative for that preparation: it provides algorithmic problems with test cases, multiple difficulty levels, and the ability to run code in the browser. The key difference is that LeetCode covers general programming challenges while iOSInterviewQuestions focuses on iOS and Apple platform specifics.

The licence is Creative Commons BY-NC-ND 3.0. This permits sharing the content with attribution but prohibits commercial use and derivative works. The materials cannot be incorporated into a paid course or modified version without violating the licence terms.

Maintenance and Accessing the Content

The repository had its last push on 2026-09-20, indicating the materials are actively maintained. The README does not provide a changelog, but the commit history tracks updates to individual answer files.

To use the repository, clone it with `git` and open the markdown files directly in any markdown reader or editor. The files are plain text and do not require any build step. GitHub's web interface renders them with working navigation links, so browsing the repository online is a zero-setup option.

The README links to WeChat and other social accounts for community discussion. The iTeaTime technology community referenced in the README is a Chinese-language discussion forum associated with the author's WeChat public account, which publishes additional interview preparation content beyond what is in this repository.

Editorial conclusion

iOSInterviewQuestions is a useful resource for iOS developers reviewing Objective-C runtime behavior, memory management, and Swift fundamentals before an interview. The Objective-C section is the most comprehensive, covering 55 questions with detailed answers. The Swift section covers theory and practical iOS topics in two separate documents. Developers who need algorithmic problem-solving practice will need to supplement this with a different resource. The repository had its last push on 2026-09-20, and the licence is Creative Commons BY-NC-ND 3.0.

Frequently asked questions

Official sources

1. ChenYilong/iOSInterviewQuestions on GitHub
2. Issues
3. README