Introduction to Swift and iOS Development with Xcode

Introduction

• Writing iOS apps with Xcode (Apple's IDE)
• Programming language: Swift (recommended over Objective-C)

Swift Programming Basics

Variables

• Immutable vs Mutable
  • Immutable: Declared with let, cannot change value once set
  • Mutable: Declared with var, value can be changed
• Syntax: let/var variableName: Type = value

Data Types

• Built-in Types: Integers, Doubles, Floats, Strings (all capitalized)
• Additional Types: Arrays, Dictionaries

Variable Declaration

• Mutable: var count = 50
• Immutable: let title: String = "..."
• Type inference capability

Conditions and Printing

• Conditionals: No need for parentheses around conditions
  • Example: if condition { ... } else { ... }
• print function: Simplified from printf (no %d, %f necessary)

Arrays

• Declaration: let values: [Int] = [1, 2, 3]
• Iteration: for value in values { ... }

Dictionaries

• Declaration: let airports: [String: String] = ["SFO": "San Francisco", "BOS": "Boston"]
• Iteration: for (code, name) in airports { ... }
• String interpolation: print("\(code), \(name)")

Functions in Swift

• Function syntax: func functionName(parameters) -> ReturnType { ... }
• Example: func sayHello(name: String) -> String { ... }
• Note: No semicolons required

Calling Functions

• Syntax: functionName(parameterName: value)

Structs and Classes

Structs

• Like containers for data
• Example: struct Course { let name: String let instructor: String }

Classes

• More powerful, can contain methods
• Declaring a class: class ClassName { ... }
• Example: class Person { var name: String init(name: String) { ... } func sayHello() { ... } }
• Instantiation: let person = Person(name: "Tommy")

Methods

• Defined inside classes
• Example: func sayHello() { ... }

Inheritance

• Subclassing: class SubclassName: SuperclassName { ... }
• Overriding methods with override: override func methodName() { ... }

Advanced Concepts

Protocols (Interfaces)

• Declaring protocols: protocol ProtocolName { func methodName() }
• Using protocols in classes: class ClassName: ProtocolName { ... }

Optionals

• Optional Type: var name: String?
• Handling optionals: if let unwrapped = optional { ... } else { ... }
• Implicit Unwrapping: Dangerous for app crashes
• Guard Clauses: guard let unwrapped = optional else { ... }

Writing Your First Swift Code

Xcode Setup

• Opening Xcode and creating a new project
• Project Details:
  • Product name
  • Organization name and identifier
  • Language: Swift

Writing Code in Xcode

• Example: Sorting Hat program
• Declaring a class: class Track { let name: String let instructor: String init(name: String, instructor: String) { ... } }
• Creating instances: let tracks = [Track(name: "Mobile", instructor: "Tommy"), ...]
• Iterating and Assigning: for student in students { let track = tracks[Int.random(in: 0..<tracks.count)] assignments[student] = track }
• Printing assignments: for (student, track) in assignments { print("\(student) got \(track.name) with \(track.instructor)") }