Answering The Most Common Questions About Swift

$(SRCROOT)/Folder/Folder/<#YourProjectName#>-Bridging-Header.h

#import <Foundation/Foundation.h>

@interface CustomObject : NSObject

@property (strong, nonatomic) id someProperty;

- (void) someMethod;

@end

#import "CustomObject.h"

@implementation CustomObject 

- (void) someMethod {
    NSLog(@"SomeMethod Ran");}

@end

#import "CustomObject.h"

var instanceOfCustomObject = CustomObject()
instanceOfCustomObject.someProperty = "Hello World"
print(instanceOfCustomObject.someProperty)
instanceOfCustomObject.someMethod()

import Foundation

@objc(MySwiftObject)class MySwiftObject : NSObject {

    @objc
    var someProperty: AnyObject = "Some Initializer Val" as NSString

    init() {}

    @objc
    func someFunction(someArg: Any) -> NSString {
        return "You sent me \(someArg)"
    }}

#import "<#YourProjectName#>-Swift.h"

MySwiftObject * myOb = [MySwiftObject new];
NSLog(@"MyOb.someProperty: %@", myOb.someProperty);
myOb.someProperty = @"Hello World";
NSLog(@"MyOb.someProperty: %@", myOb.someProperty);

NSString * retString = [myOb someFunctionWithSomeArg:@"Arg"];

NSLog(@"RetString: %@", retString);

// MARK:

// MARK: your text goes here

// MARK: - your text goes here

test1.count

test1.characters.count

let unusualMenagerie = "Koala 🐨, Snail 🐌, Penguin 🐧, Dromedary 🐪"
println("unusualMenagerie has \(count(unusualMenagerie)) characters")
// prints "unusualMenagerie has 40 characters"

length = count(test1) // was countElements in earlier versions of Swift

test1.characters.count

var emoji = "👍"
emoji.characters.count             //returns 1
emoji.utf16.count                  //returns 2

for (index, element) in list.enumerated() {
  print("Item \(index): \(element)")}

for (index, element) in list.enumerate() {
    print("Item \(index): \(element)")}

for (index, element) in enumerate(list) {
    println("Item \(index): \(element)")}

func enumerated() -> EnumeratedSequence<Array<Element>>

let list = ["Car", "Bike", "Plane", "Boat"]
for (index, element) in list.enumerated() {
    print(index, ":", element)
}

/*
prints:
0 : Car
1 : Bike
2 : Plane
3 : Boat
*/

let list = [Int](1...5)
var arrayOfTuples = [(Int, Int)]()

for (index, element) in list.enumerated() {
    arrayOfTuples += [(index, element)]}

print(arrayOfTuples) // prints [(0, 1), (1, 2), (2, 3), (3, 4), (4, 5)]

let list = [Int](1...5)
let arrayOfTuples = Array(list.enumerated())
print(arrayOfTuples) // prints [(offset: 0, element: 1), (offset: 1, element: 2), (offset: 2, element: 3), (offset: 3, element: 4), (offset: 4, element: 5)]

let list = [Int](1...5)
let arrayOfDictionaries = list.enumerated().map { (a, b) in return [a : b] }
print(arrayOfDictionaries) // prints [[0: 1], [1: 2], [2: 3], [3: 4], [4: 5]]

let list = [Int](1...5)
list.reversed().enumerated().forEach { print($0, ":", $1) }

/*
prints:
0 : 5
1 : 4
2 : 3
3 : 2
4 : 1
*/

import UIKitimport PlaygroundSupport

class ViewController: UIViewController {

    var generator = ["Car", "Bike", "Plane", "Boat"].enumerated().makeIterator()

    override func viewDidLoad() {
        super.viewDidLoad()

        let button = UIButton(type: .system)
        button.setTitle("Tap", for: .normal)
        button.frame = CGRect(x: 100, y: 100, width: 100, height: 100)
        button.addTarget(self, action: #selector(iterate(_:)), for: .touchUpInside)
        view.addSubview(button)
    }

    @objc func iterate(_ sender: UIButton) {
        let tuple = generator.next()
        print(String(describing: tuple))
    }

}

PlaygroundPage.current.liveView = ViewController()

/*
 Optional((offset: 0, element: "Car"))
 Optional((offset: 1, element: "Bike"))
 Optional((offset: 2, element: "Plane"))
 Optional((offset: 3, element: "Boat"))
 nil
 nil
 nil
 */

#if DEBUG
    let a = 2
#else
    let a = 3
#endif

#if BANANA
    print("We have a banana")
#elseif MELONA
    print("Melona")
#else
    print("Kiwi")
#endif

var fullName = "First Last"
var fullNameArr = split(fullName) {$0 == " "}
var firstName: String = fullNameArr[0]
var lastName: String? = fullNameArr.count > 1 ? fullNameArr[1] : nilW

let fullName = "First Last"
let fullNameArr = fullName.characters.split{$0 == " "}.map(String.init)// or simply:
// let fullNameArr = fullName.characters.split{" "}.map(String.init)

fullNameArr[0] // First
fullNameArr[1] // Last 

import Foundation

var fullName: String = "First Last"let fullNameArr = fullName.componentsSeparatedByString(" ")

var firstName: String = fullNameArr[0]
var lastName: String = fullNameArr[1]

import Foundation

let fullName    = "First Last"
let fullNameArr = fullName.components(separatedBy: " ")

let name    = fullNameArr[0]
let surname = fullNameArr[1]

let timer = Timer(timeInterval: 1, target: object,
                  selector: #selector(MyClass.test),
                  userInfo: nil, repeats: false)
button.addTarget(object, action: #selector(MyClass.buttonTapped),
                 for: .touchUpInside)
view.perform(#selector(UIView.insertSubview(_:aboveSubview:)),
             with: button, with: otherButton)

override func viewDidLoad() {
    super.viewDidLoad()

    var rightButton = UIBarButtonItem(title: "Title", style: UIBarButtonItemStyle.Plain, target: self, action: Selector("method"))
    self.navigationItem.rightBarButtonItem = rightButton
}

func method() {
    // Something cool here   
}

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: NSDictionary?) -> Bool {
    self.window = UIWindow(frame: UIScreen.mainScreen().bounds)

    var controller = UIViewController()
    var view = UIView(frame: CGRectMake(0, 0, 320, 568))
    view.backgroundColor = UIColor.redColor()
    controller.view = view

    var label = UILabel(frame: CGRectMake(0, 0, 200, 21))
    label.center = CGPointMake(160, 284)
    label.textAlignment = NSTextAlignment.Center
    label.text = "I'am a test label"
    controller.view.addSubview(label)

    self.window!.rootViewController = controller
    self.window!.makeKeyAndVisible()
    return true}

class Singleton  {
   static let sharedInstance = Singleton()
}

class Singleton {
    class var sharedInstance: Singleton {
        struct Static {
            static let instance: Singleton = Singleton()
        }
        return Static.instance
    }
}

class Singleton {
    class var sharedInstance: Singleton {
        struct Static {
            static var onceToken: dispatch_once_t = 0
            static var instance: Singleton? = nil
        }
        dispatch_once(&Static.onceToken) {
            Static.instance = Singleton()
        }
        return Static.instance!
    }
}

protocol ProtocolNameDelegate: AnyObject {
    // Protocol stuff goes here
}

class SomeClass {
    weak var delegate: ProtocolNameDelegate?
}

protocol MyClassDelegate: AnyObject {
    // ...
}

class SomeClass {
    weak var delegate: MyClassDelegate?
}

let x : Int = 42
var myString = String(x)

let myString : String = "42"
let x: Int? = myString.toInt()

if (x != nil) {
    // Successfully converted String to Int
}

let x: Int? = Int(myString)

let x : Int = 45
var stringValue = "\(x)"
print(stringValue)