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iOS Developer Interview Questions

What's the difference between a view's initializer and onAppear()?

Suggested approach: Using init() and onAppear() both let us run some code early in a view's lifecycle, however it's important to understand the difference between them.

SwiftUI creates all its view structs immediately, even creating destination views for navigation links, which means that initializers are run immediately and that's probably not something you want. In comparison, code placed in an onAppear() modifier is called only when the view is shown for the first time, so it's the right place to do complex work.

  Estimated difficulty: Easy

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Important notes

  • There are over 150 interview questions in the system. Once you've read the question and come up with a suitable answer, try reading my suggested approach and see if it helps you add more detail.
  • These questions are not designed to be hard; a good interviewer is more interested in generating discussion that lets your ability and interests shine through.
  • If you answer a question with "yes" or "no" you've missed the point – interviewers prefer you to provide reasoning, explanation, or detail, so try to elaborate with examples!
  • If you're looking for detailed technical questions about the language, you should try my Swift tests instead – there are multiple challenges that will work your brain hard.
  • For a whole series of coding challenges, I wrote the perfect book for you: Swift Coding Challenges.

Related questions

See the full list of iOS interview questions

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