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Beginner Topic 4 of 50 Mobile, Embedded & IoT

iOS Basics

App structure and tooling on Apple devices.

How it works

iOS apps are written mainly in Swift, with UIKit or the declarative SwiftUI framework, and built in Xcode. An app runs in a sandbox with an app delegate or scene lifecycle, with states such as active, inactive, background and suspended. Architecture patterns such as MVC, MVVM and combine or async-await handle data flow, and storage options include UserDefaults, the Keychain, Core Data and SwiftData. Capabilities and entitlements, privacy usage descriptions and App Store review govern distribution and access to features.

Where it is used

iPhone and iPad apps, watchOS, tvOS and visionOS apps share much of the tooling and language.

Common pitfall

Retain cycles with closures and delegates leak memory, so use weak references. Updating UI off the main thread crashes or glitches. Background execution is strictly limited. Missing privacy strings crash the app on permission requests. App Store guidelines and certificate and provisioning profile management trip up newcomers. Test on devices, use Instruments to profile and plan for yearly OS updates.

Where it fits in the course

iOS Basics is topic 4 of 50 in Mobile, Embedded & IoT, rated Beginner. It follows Android Basics. The next topic is Cross-Platform Frameworks.

Practice and explore

How to study this topic

  1. Read the explanation above and restate the definition in your own words.
  2. Open the interactive lesson and answer its mini quiz.
  3. Read the common pitfall, then write a short example that avoids it.
  4. Check your understanding in the Mobile, Embedded & IoT quiz, and revisit the topic if you miss a question.

Frequently asked questions

What is iOS Basics?
App structure and tooling on Apple devices. It belongs to Mobile, Embedded & IoT and is a beginner-level topic.
Where do people use iOS Basics?
iPhone and iPad apps, watchOS, tvOS and visionOS apps share much of the tooling and language.
What is the most common mistake with iOS Basics?
Retain cycles with closures and delegates leak memory, so use weak references.
What should I learn before this topic?
Start with Android Basics, the topic just before it in Mobile, Embedded & IoT.
How can I practice it?
Answer the mini quiz in the interactive lesson, then take the Mobile, Embedded & IoT quiz.
Is iOS Basics hard to learn?
It is a Beginner topic, so it works as an entry point. If the terms are new, read the explanation twice and try the visualizer before the quiz.
How long does it take to learn iOS Basics?
Most learners can read the explanation and finish the interactive lesson in under an hour. Fluency comes from applying the idea, so plan a few short practice sessions with the quiz.
Which topics are related to iOS Basics?
Android Basics, Cross-Platform Frameworks, Mobile UI Principles are closely connected. The full list is in the related topics section of this page.
What should I study after iOS Basics?
Continue with Cross-Platform Frameworks, the next topic in Mobile, Embedded & IoT.

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