Swift

export PATH=/Library/Developer/Toolchains/swift-latest.xctoolchain/usr/bin:"${PATH}"

Hello World

import UIKit

class ViewController: UIViewController {
    
    @IBOutlet weak var nameTexField: UITextField!
    @IBOutlet weak var ageTextField: UITextField!
    @IBOutlet weak var helloLabel: UILabel!
    

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func clickMeAction(_ sender: Any) {
        print("Hello \(nameTexField.text!)");
        helloLabel.text = "Hello \(nameTexField.text!), your age is \(ageTextField.text!)";
    }
}

Alert & Action

import UIKit

class ViewController: UIViewController {
    
    @IBOutlet weak var nameTexField: UITextField!
    @IBOutlet weak var ageTextField: UITextField!
    @IBOutlet weak var helloLabel: UILabel!
    

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func clickMeAction(_ sender: Any) {
        print("Hello \(nameTexField.text!)")
        helloLabel.text = "Hello \(nameTexField.text!), your age is \(ageTextField.text!)"
    }
    
    @IBAction func showAlertAction(_ sender: UIButton) {
        let alertCtrl = UIAlertController(title: "Alert", message: "Hello Alert", preferredStyle: .alert)
        let destructiveAction = UIAlertAction(title: "Delete", style: .destructive, handler: nil)
        let cancelAction = UIAlertAction(title: "Cancel", style: .default, handler: nil)
        let okAction = UIAlertAction(title: "OK", style: .cancel, handler: nil)
        alertCtrl.addAction(okAction)
        alertCtrl.addAction(cancelAction)
        alertCtrl.addAction(destructiveAction)
        present(alertCtrl, animated: true, completion: nil)
    }
    
    @IBAction func showConfirmAction(_ sender: UIButton) {
        let actionSheet = UIAlertController(title: "Hello World", message: "This is an Action Sheet", preferredStyle: .actionSheet)
        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
        let okAction = UIAlertAction(title: "OK", style: .default, handler: nil)
        actionSheet.addAction(okAction)
        actionSheet.addAction(cancelAction)
        present(actionSheet, animated: true, completion: nil)
    }
}

Playground

import UIKit

var hello = "Hello, playground"
print(hello)

// 1) constrant vs variable
var name = "Raiyan Bin Shahed" //mutable and variable
let greetings = "Hello"        //immutable and constrant
let message = greetings + name
print(message)

name = "Shahed Hossain"
print(name)

// 2) Implicit vs Explicit typing
let huaweiPrice:Double = 2999 //Explicit Typing
let deliveryCharge = 9.99     //Implicit Typing
let totalPrice = huaweiPrice + deliveryCharge
print(totalPrice)

// 3) If else in Swift
// No need to end statement in semicolon (optional)
// Conditional bracket is optional
// The curly bracket is compulsary even it is for one liner statement
let hungry = true
if hungry {
    print("Let's have a break now")
}
else {
    print("Let's have a break in 15 minutes")
}


// 4) Array and For Loop
var myArray = [2, 4, 6, 8, 10]
myArray.append(12) //add item
print(myArray.count) // length
print(myArray[1]) //accessing 2nd item by index


// 4) For Loop in Swift
//  collection for loop
for item in myArray {
    print(item)
}

// incrementaql for loop
for i in 0..<myArray.count {
    print("Item \(i) is \(myArray[i])") //interpolation
}

// 5) Dictionary
let myInfo    = ["name": "Shahed Hossain", "city": "KLC", "phone": "01117606778", "email": "[email protected]"]
let mySonInfo = ["name": "Raiyan Bin Shahed", "city": "KLC", "phone": "01117606778"]
// When we get a value from dictionary, we will get optional data type,
// Since it can be nil or it can eturn a value
print(myInfo["name"])
print(mySonInfo["email"])

// To get the value, you can use
// 5.1) Optional Binding
// Have to write more code but null safe
// Safe for runtime as well as production
if let newVar = myInfo["name"] {
    print(newVar)
}

// 5.2) Force unwrap
print(myInfo["name"]!) // easy to write but not null safe

Switcher and Slider

iimport UIKit

class ViewController: UIViewController {

    @IBOutlet weak var priceFilter: UISwitch!
    @IBOutlet weak var priceSlider: UISlider!
    @IBOutlet weak var priceLabel: UILabel!
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }


    @IBAction func switchFilterAction(_ sender: UISwitch) {
        if priceFilter.isOn {
            priceSlider.isEnabled = true
            priceLabel.isHidden = false
            priceLabel.text = String(format:"%2.2f", priceSlider.value)
        }
        else {
            priceSlider.isEnabled = false
            priceLabel.isHidden = true
        }
    }
    
    
    @IBAction func whenPriceUpdated(_ sender: UISlider) {
        priceLabel.text = String(format:"%2.2f", priceSlider.value)
    }
}

Features

1. Closures unified with function pointers
2. Tuples and multiple return values
3. Generics
4. Fast and concise iteration over a range or collection
5. Structs that support methods, extensions, and protocols
6. Functional programming patterns, e.g., map and filter
7. Powerful error handling built-in
8. Advanced control flow with do, guard, defer, and repeat keywords

References

• Swift LLVM, Swift Docker
• Swift, Swift Clang
• Swift Cheat Sheet
• iOS Chat Tutorial
• Swift Community
• Download Swift
• About Swift