IOSWith Swift UIStudy Notes

App and Scene Structure

Understand how the App and Scene protocols define a SwiftUI application's entry point, window management, and lifecycle across platforms.

App Lifecycle in SwiftUI

How SwiftUI apps start, move through foreground/background states, and respond to system events using the App protocol, Scene, and scenePhase.

async/await Basics in Swift

Learn how Swift's async/await syntax replaces completion-handler callbacks with linear, readable asynchronous code, and how to call async functions safely.

Buttons and User Input in SwiftUI

Learn how SwiftUI captures user intent through Button, Toggle, Slider, Stepper, and TextField, and how actions drive state changes in a declarative UI.

Codable and JSON Parsing

Learn how Swift's Codable protocol pair enables automatic, type-safe encoding and decoding between Swift types and formats like JSON.

Combine Framework Fundamentals

Understand Combine's publisher-subscriber model for handling asynchronous event streams in Swift, and how it relates to async/await and SwiftUI.

Common iOS & SwiftUI Pitfalls

Frequent mistakes SwiftUI developers make around state ownership, list identity, concurrency, and view identity, with clear explanations of why they break.

Dependency Injection in SwiftUI

Learn how to supply view models and services to SwiftUI views through initializers and the environment, keeping views testable and decoupled from concrete impl…

@EnvironmentObject Basics

Learn how @EnvironmentObject injects a shared model into the SwiftUI view hierarchy so deeply nested views can access it without manual parameter passing.

Human Interface Guidelines and Theming

How to apply Apple's Human Interface Guidelines in SwiftUI apps using semantic colors, Dynamic Type, dark mode, and adaptive layout so apps feel native.

iOS & SwiftUI Interview Questions

A curated set of common iOS and SwiftUI interview questions covering state management, concurrency, architecture, and performance, with clear answers.

iOS & SwiftUI Quick Reference

A condensed cheat sheet of core SwiftUI property wrappers, layout containers, navigation APIs, and concurrency tools for quick lookup while coding.

LazyVStack and LazyHStack

Understand how LazyVStack and LazyHStack defer creation of off-screen views inside a ScrollView, enabling efficient custom scrolling layouts.

List and ForEach

Learn how List renders scrollable, platform-styled collections and how ForEach generates repeated views from a data collection using stable identity.

List Performance in SwiftUI

Learn how SwiftUI's List actually renders and recycles rows, and the concrete techniques for keeping scrolling smooth in large or complex data sets.

Modifiers in SwiftUI

How view modifiers work under the hood, why order matters, and how chained modifiers build up new wrapped view types.

MVVM in SwiftUI

Understand how the Model-View-ViewModel pattern maps onto SwiftUI's declarative views, when it earns its complexity, and how it differs from plain @State-drive…

NavigationPath and Programmatic Navigation

Learn how NavigationPath lets you drive SwiftUI navigation from code — deep linking, popping to root, and building multi-step flows without user taps.

NavigationStack Basics

Understand how NavigationStack replaced NavigationView, how navigationDestination drives push navigation, and how to structure hierarchical screens in SwiftUI.

Networking with URLSession

Understand how URLSession performs HTTP requests in Swift, including async/await APIs, request configuration, and handling responses safely.

ObservableObject and @ObservedObject

Learn how the pre-iOS 17 ObservableObject protocol and @Published/@ObservedObject let reference-type models publish changes that drive SwiftUI view updates.

Passing Data Between Views

A practical guide to the different ways data flows through a SwiftUI view hierarchy — initializers, @Binding, environment, and shared observable models.

Publishers and @MainActor

Learn how to safely deliver Combine publisher values to the main thread using @MainActor and .receive(on:), and how actor isolation interacts with reactive pip…

Stacks: VStack, HStack, and ZStack

How SwiftUI's three core layout containers arrange child views vertically, horizontally, and by depth, plus alignment and spacing controls.