HomeCode AINewsletter

Swift

Swift is a powerful and modern programming language developed by Apple for building iOS, macOS, watchOS, and tvOS applications. It is designed to be safe, fast, and expressive, with a syntax that is concise and easy to read. Swift combines features from multiple programming paradigms, including object-oriented and functional programming. Swift's strong typing and memory management capabilities make it a reliable choice for building efficient and secure applications.

Module 1: Swift Basics

Introduction to Swift

Swift is a powerful, intuitive programming language developed by Apple for iOS, macOS, watchOS, and tvOS. Its clean slate, backed-up by the mature and much-loved Cocoa and Cocoa Touch frameworks, is an opportunity to reimagine how software development works.

print('Hello, Swift!')

Variables, Constants, and Data Types

Swift provides powerful, yet easy-to-use, ways of defining variables and constants using simple, clear syntax. The Swift language also supports several primitive data types, including Integer, Double, Float, Boolean, and String.

var myVariable = 42
let myConstant = 3.14159
let explicitDouble: Double = 70

Control Flow

Swift provides a variety of control flow statements. These include while loops to perform a task multiple times; if, guard, and switch statements to execute different branches of code based on certain conditions; and statements such as break and continue to transfer the flow of execution to another point in your code.

let individualScores = [75, 43, 103, 87, 12]
var teamScore = 0
for score in individualScores {
	if score > 50 {
		teamScore += 3
	} else {
		teamScore += 1
	}
}

Module 2: Object-Oriented Programming in Swift

Classes and Objects

Classes are general-purpose, flexible constructs that become the building blocks of your program's code. Unlike other programming languages, Swift classes do not inherit from a universal base class. Classes in Swift can call and access methods, properties, and subscripts belonging to their superclass and can provide their own overridden versions of those methods, properties, and subscripts.

class Shape {
	var numberOfSides = 0
	func simpleDescription() -> String {
		return 'A shape with \(numberOfSides) sides.'
	}
}

Inheritance

A class can inherit methods, properties, and other characteristics from another class. Swift classes can also call and access methods, properties, and subscripts belonging to their superclass and can provide their own overridden versions.

class Square: Shape {
	var sideLength: Double
	init(sideLength: Double, name: String) {
		self.sideLength = sideLength
		super.init(name: name)
		numberOfSides = 4
	}

	func area() -> Double {
		return sideLength * sideLength
	}
}

Protocols and Extensions

Protocols define a blueprint of methods, properties, and other requirements that suit a particular task or piece of functionality. Extensions add new functionality to an existing class, structure, enumeration, or protocol type, and they can also provide implementations for protocol methods.

protocol ExampleProtocol {
	var simpleDescription: String { get }
	mutating func adjust()
}
class SimpleClass: ExampleProtocol {
	var simpleDescription: String = 'A very simple class.'
	var anotherProperty: Int = 69105
	func adjust() {
		simpleDescription += '  Now 100% adjusted.'
	}
}

Module 3: Advanced Swift Concepts

Error Handling

You use error handling to respond to error conditions your program may encounter during execution. Swift provides first-class support for throwing, catching, propagating, and manipulating recoverable errors at runtime.

func canThrowAnError() throws {
	// this function may or may not throw an error
}
do {
	try canThrowAnError()
	// no error was thrown
} catch {
	// an error was thrown
}

Generics

Generic code enables you to write flexible, reusable functions and types that can work with any type, subject to requirements that you define. You can write code that avoids duplication and expresses its intent in a clear, abstracted manner.

func makeArray<Item>(repeating item: Item, numberOfTimes: Int) -> [Item] {
	var result = [Item]()
	for _ in 0..<numberOfTimes {
		result.append(item)
	}
	return result
}

Concurrency and Multithreading

Swift provides language-level support for concurrent and asynchronous operations with features like DispatchQueues and Tasks, which are key to building responsive and efficient applications.

import Dispatch
let queue = DispatchQueue.global()
queue.async {
	for i in 0..<10 {
		print('🔵', i)
	}
}
for i in 100..<110 {
	print('🔴', i)
}

Module 4: Swift and UIKit

Introduction to UIKit

UIKit is the framework you’ll use to build your interface when programming iOS applications using Swift. It provides a set of tools and objects for building graphical interfaces.

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .blue
    }
}

Views and View Controllers

The visual content of an iOS app is a hierarchy of views that are managed by view controllers. A view controller manages a single root view, which may itself contain any number of subviews.

class CustomViewController: UIViewController {
    let customView = UIView()

    override func viewDidLoad() {
        super.viewDidLoad()

        customView.frame = CGRect(x: 0, y: 0, width: 200, height: 200)
        customView.backgroundColor = .red
        view.addSubview(customView)
    }
}

Navigation and Segues

Segues are a very important part of using Storyboards in Xcode. Segues are the lines that connect two view controllers in Storyboard. They represent the transition from one view to another.

// In a view controller
performSegue(withIdentifier: 'showSecondViewController', sender: self)

// Implement this function in the view controller
class FirstViewController: UIViewController {
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == 'showSecondViewController' {
            let secondVC = segue.destination as! SecondViewController
            secondVC.data = 'Hello, second view controller!'
        }
    }
}

Module 5: Swift and SwiftUI

Introduction to SwiftUI

SwiftUI is a revolutionary development framework that makes building interfaces across all Apple platforms as easy as dragging and dropping. As a declarative Swift-based UI framework, it enables developers to write easy-to-read, maintainable, and reusable code.

import SwiftUI

struct ContentView: View {
    var body: some View {
        Text('Hello, SwiftUI!')
    }
}

SwiftUI Views, Modifiers, and Stacks

Views are the basic building blocks of your app's user interface, and the SwiftUI framework provides a large selection of views. You can customize the appearance and interaction behavior of a view using modifiers, and you can combine views in stacks.

import SwiftUI

struct ContentView: View {
    var body: some View {
        VStack {
            Text('Hello')
            Text('SwiftUI')
        }.font(.largeTitle)
    }
}

Navigation in SwiftUI

SwiftUI provides several tools for developers to manage the navigation in their apps, such as navigating to a new screen by pushing a new view onto the navigation stack, presenting content modally, and creating tab-based layouts.

import SwiftUI

struct ContentView: View {
    var body: some View {
        NavigationView {
            VStack {
                NavigationLink(destination: DetailView()) {
                    Text('Go to Detail View')
                }
            }.navigationBarTitle('Home')
        }
    }
}

struct DetailView: View {
    var body: some View {
        Text('Detail View')
    }
}