Swiftly Switching: The Transition from Obj-C to Swift
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The document provides an overview of transitioning from Objective-C to Swift, highlighting Swift's advantages such as concise syntax, ease of use, and interoperability with existing Objective-C code. It contrasts common programming patterns in both languages, including class definitions, property declarations, and method calls, illustrating how Swift simplifies these tasks. Additionally, it addresses Swift's features like optionals, type inference, and cleaner syntax for collections and iterations.
![BRACKETS & SEMICOLONS
Objective-C
@MaeganSnee
UIView *subView = [[UIView alloc] !
initWithFrame:CGRectMake(50, 50, 100, 100)];!
subView.backgroundColor = [UIColor redColor];!
[[self view] addSubview:subView];!
Swift
let subView:UIView = UIView.init(frame: !
CGRectMake(50, 50, 100, 100))!
subView.backgroundColor = UIColor.redColor()!
self.view.addSubview(subView)!](https://image.slidesharecdn.com/swiftlyswitching-150918182916-lva1-app6892/85/Swiftly-Switching-The-Transition-from-Obj-C-to-Swift-9-320.jpg)
![AMOUNT OF CODE
Objective-C
@MaeganSnee
@property (strong, nonatomic) IBOutlet UITextField *input;!
@property (strong, nonatomic) IBOutlet UILabel *label;!
!
[self.label setText:[NSString stringWithFormat:@"Welcome, !
%@!", self.input.text]];!
Swift
@IBOutlet var input: UITextField!!
@IBOutlet var label: UILabel!!
!
label.text = "Welcome, (input.text)!"!](https://image.slidesharecdn.com/swiftlyswitching-150918182916-lva1-app6892/85/Swiftly-Switching-The-Transition-from-Obj-C-to-Swift-10-320.jpg)
![EASE OF USE
Objective-C
@MaeganSnee
// defining a method!
- (void)changeImage:(int)num { ... }!
!
// calling the method!
[self changeImage:number];!
!
Swift
// defining a method!
func changeImage(num:Int) { ... }!
!
// calling the method!
changeImage(number)!](https://image.slidesharecdn.com/swiftlyswitching-150918182916-lva1-app6892/85/Swiftly-Switching-The-Transition-from-Obj-C-to-Swift-11-320.jpg)
![SHORTER SYNTAX
Objective-C
@MaeganSnee
@property (strong, nonatomic) IBOutlet UITextField *input;!
@property (strong, nonatomic) IBOutlet UILabel *label;!
!
[self.label setText:[NSString stringWithFormat:@"Welcome, !
%@!", self.input.text]];!
Swift
@IBOutlet var input: UITextField!!
@IBOutlet var label: UILabel!!
!
label.text = "Welcome, (input.text)!"!](https://image.slidesharecdn.com/swiftlyswitching-150918182916-lva1-app6892/85/Swiftly-Switching-The-Transition-from-Obj-C-to-Swift-13-320.jpg)
![STRING INTERPOLATION
Objective-C
@MaeganSnee
int age = 3;!
NSString *name = "Tardar Sauce";!
NSString *funFact = [NSString stringWithFormat:@"Grumpy!
Cat’s real name is %@ and she is %d !
years old.", name, age];!
Swift
let age:Int = 3!
let name:String = "Tardar Sauce"!
let funFact:String = "Grumpy Cat’s real name is (name) !
and she is (age) years old"!](https://image.slidesharecdn.com/swiftlyswitching-150918182916-lva1-app6892/85/Swiftly-Switching-The-Transition-from-Obj-C-to-Swift-15-320.jpg)
![SIMPLE DEFINITIONS (ARRAY)
Objective-C
@MaeganSnee
NSMutableArray *emptyArray = [[NSMutableArray alloc]init];!
!
NSArray *array = [NSArray arrayWithObjects: @"kids", !
@"wife", @"husband", nil];!
Swift
var emptyArray = [String]()!
!
let array = ["kids", "wife", "husband"]!](https://image.slidesharecdn.com/swiftlyswitching-150918182916-lva1-app6892/85/Swiftly-Switching-The-Transition-from-Obj-C-to-Swift-16-320.jpg)
![SIMPLE DEFINITIONS (DICTIONARY)
Objective-C
@MaeganSnee
NSMutableDictionary *emptyDictionary = !
[[NSMutableDictionary alloc] init];!
!
NSDictionary *dictionary= @{!
@"first" : @"Leeroy",!
@"last" : @"Jenkins"!
};!
Swift
var emptyDictionary = Dictionary()!
!
var dictionary = [!
"first" : "Leeroy",!
"last" : "Jenkins"!
]!](https://image.slidesharecdn.com/swiftlyswitching-150918182916-lva1-app6892/85/Swiftly-Switching-The-Transition-from-Obj-C-to-Swift-18-320.jpg)
![ITERATIONS (DICTIONARY)
Objective-C
@MaeganSnee
for (id key in dictionary) {!
NSLog(@"Player’s %@ name is %@.", key, !
dictionary[key]);!
}!
!
Swift
for (key, value) in dictionary {!
print("Player’s (key) name is (value).")!
}!](https://image.slidesharecdn.com/swiftlyswitching-150918182916-lva1-app6892/85/Swiftly-Switching-The-Transition-from-Obj-C-to-Swift-19-320.jpg)
Swiftly Switching: The Transition from Obj-C to Swift
- 1. Swiftly Switching: The Transition from Obj-C to Swift Big Design Dallas 2015 | @MaeganSnee
- 5. Objective-C is the primary programming language you use when writing software for OS X and iOS. It’s a superset of the C programming language and provides object- oriented capabilities and a dynamic runtime. Swift is a powerful and intuitive programming language for iOS, OS X, and watchOS. Writing Swift code is interactive and fun, the syntax is concise yet expressive, and apps run lightning- fast. Swift is ready for your next project — or addition into your current app — because Swift code works side-by-side with Objective-C. @MaeganSnee developer.apple.com
- 8. @interface ViewController : UIViewController! ! @property (strong, nonatomic) IBOutlet UITextField *textField;! @property (strong, nonatomic) IBOutlet UIImageView *imageView;! ! @end! HEADER FILES Objective-C @MaeganSnee Swift class ViewController: UIViewController {! ! @IBOutlet var imageView: UIImageView!! @IBOutlet var textField: UITextField!! ! }!
- 9. BRACKETS & SEMICOLONS Objective-C @MaeganSnee UIView *subView = [[UIView alloc] ! initWithFrame:CGRectMake(50, 50, 100, 100)];! subView.backgroundColor = [UIColor redColor];! [[self view] addSubview:subView];! Swift let subView:UIView = UIView.init(frame: ! CGRectMake(50, 50, 100, 100))! subView.backgroundColor = UIColor.redColor()! self.view.addSubview(subView)!
- 10. AMOUNT OF CODE Objective-C @MaeganSnee @property (strong, nonatomic) IBOutlet UITextField *input;! @property (strong, nonatomic) IBOutlet UILabel *label;! ! [self.label setText:[NSString stringWithFormat:@"Welcome, ! %@!", self.input.text]];! Swift @IBOutlet var input: UITextField!! @IBOutlet var label: UILabel!! ! label.text = "Welcome, (input.text)!"!
- 11. EASE OF USE Objective-C @MaeganSnee // defining a method! - (void)changeImage:(int)num { ... }! ! // calling the method! [self changeImage:number];! ! Swift // defining a method! func changeImage(num:Int) { ... }! ! // calling the method! changeImage(number)!
- 13. SHORTER SYNTAX Objective-C @MaeganSnee @property (strong, nonatomic) IBOutlet UITextField *input;! @property (strong, nonatomic) IBOutlet UILabel *label;! ! [self.label setText:[NSString stringWithFormat:@"Welcome, ! %@!", self.input.text]];! Swift @IBOutlet var input: UITextField!! @IBOutlet var label: UILabel!! ! label.text = "Welcome, (input.text)!"!
- 14. CLEANER CLASSES Objective-C @MaeganSnee #import "ViewController.h”! ! @implementation ViewController! // methods! @end! Swift class ViewController: UIViewController {! // properties and methods! }!
- 15. STRING INTERPOLATION Objective-C @MaeganSnee int age = 3;! NSString *name = "Tardar Sauce";! NSString *funFact = [NSString stringWithFormat:@"Grumpy! Cat’s real name is %@ and she is %d ! years old.", name, age];! Swift let age:Int = 3! let name:String = "Tardar Sauce"! let funFact:String = "Grumpy Cat’s real name is (name) ! and she is (age) years old"!
- 16. SIMPLE DEFINITIONS (ARRAY) Objective-C @MaeganSnee NSMutableArray *emptyArray = [[NSMutableArray alloc]init];! ! NSArray *array = [NSArray arrayWithObjects: @"kids", ! @"wife", @"husband", nil];! Swift var emptyArray = [String]()! ! let array = ["kids", "wife", "husband"]!
- 17. ITERATIONS (ARRAY) Objective-C @MaeganSnee for (NSString *value in array) {! NSLog(@"Hide yo’ %@.", value);! }! ! ! ! Swift for value in array {! print("Hide yo’ (value).”)! }!
- 18. SIMPLE DEFINITIONS (DICTIONARY) Objective-C @MaeganSnee NSMutableDictionary *emptyDictionary = ! [[NSMutableDictionary alloc] init];! ! NSDictionary *dictionary= @{! @"first" : @"Leeroy",! @"last" : @"Jenkins"! };! Swift var emptyDictionary = Dictionary()! ! var dictionary = [! "first" : "Leeroy",! "last" : "Jenkins"! ]!
- 19. ITERATIONS (DICTIONARY) Objective-C @MaeganSnee for (id key in dictionary) {! NSLog(@"Player’s %@ name is %@.", key, ! dictionary[key]);! }! ! Swift for (key, value) in dictionary {! print("Player’s (key) name is (value).")! }!
- 21. VARIABLES VS. CONSTANTS Variable @MaeganSnee var language = "Objective-C"! language = "Swift"! // language is now Swift! Constant let language = "Objective-C”! language = "Swift"! // compile-time error; language cannot be changed! ! var language2 = "Swift"! // compile-time warning; “consider changing to let”!
- 22. TYPE INFERENCE Typed @MaeganSnee let number:Int = 42! let phrase:String = "meaning of life"! let decimal:Double = 3.14! ! Inferred let number = 42 // Int! let phrase = "meaning of life" // String! let decimal = 3.14 // Double!
- 23. OPTIONALS Optionals @MaeganSnee var name:String! = "Lone Wanderer" // optional String! ! var newName:String? // empty optional String! newName = "Sole Survivor" // String no longer nil! ! ! nil var westVault:Int? // initially contains no value! westVault = 101 // now has value of 101! var eastVault:Int? = 111 // initially has value of 111! eastVault = nil // now contains no value!
- 24. UNWRAPPING OPTIONALS Unwrapping @MaeganSnee if newName != nil {! print("His name is (newName!)")! }! Binding if let vaultNumber = westVault {! print("Vault (vaultNumber) is home to (name)")! } else {! print("Vault could not be located")! }!