Book Class

@interface Book : NSObject

@property (nonatomic) NSString *title;
@property (nonatomic) NSString *author;
@property (nonatomic) int yearOfPublication;

-(instancetype)initWithTitle:(NSString*)title
	author:(NSString*)author
		year:(init)year;

@end

// Book.m
@implementation Book

-(instancetype)initWithTitle:(NSString*)title
			author:(NSString*)author
			year:(int)year {

			self = [super init];
			if(self){
				_title = title;
				_author = author;
				_yearOfPublication = year;
			}
			return self;
}

@end

Weak references for:
1. delegates
2. subviews of the main view

Person.h

@interface Person : NSObject

@property (nonatomic) NSString *name;
@property (nonatomic) NSDate *birthday;

@end

Person.m

// Person.m

@implementation Person

-(instancetype)initWithName:(NSString*)name birthday:(NSDate*)birthday {
	self = [super init];

	if(self){
		_name = name;
		_birthday = birthday;
	}
	return self;
}
@end

Book.h

#import "Person.h"

@interface Book : NSObject

@property (nonatomic) NSString *title;
@property (nonatomic) Person *author;
@property (nonatomic) int yearOfPublication;

-(instancetype)initWithTitle:(NSString*)title
	author:(Person*)author
		year:(int)year;

@end

Custom Initializer

-(instancetype)initWithAddress: (NSMutableString*)address {
	self = [super init];

	if(self){
		_address = [address copy];
		_numberOfBedrooms = 3;
		_hasHotTub = false;	
	}
	return self;
}

Class initialization

#import "House.h"

@interface House()
@property (nonatomic, readwrite) int numberOfBedrooms;
@end

@implementation House

-(instancetype)initWithAddress:(NSString*)address {
	self = [super init];

	if(self){
		_address = [address copy];
		_numberOfBedrooms = 2;
		_hasHotTub = false;
	}
	return self;
}
@end

House Object Diagram

House
*address
int numberOfBedrooms
bool hasHotTub

-> address

#import <Foundation/Foundation.h>

@interface House : NSObject
@property (nonatomic) NSString *address
@property (nonatomic) int numberOfBetrooms;
@property (nonatomic) BOOL hasHotTub;

@end
#import <Foundation/Foundation.h>
#import "House.h"

#import <Foundation/Foundation.h>
#import "House.h"

int main(int argc, const char * argv[]){
	@autoreleasepool {
		House *myHouse = [[House alloc] init];

	}
	return 0;
}

Dynamic Method Resolution

#import <Foundation/Foundation.h>
#import "Puppy.h"
#import "Dealer.h"
#import "Drum.h"

int main(int argc, const char * argv[]){
	@autoreleasepool {

		Puppy *spot = [[Puppy alloc] init];
		Drum *drum = [[Drum alloc] init];
		Dealer *cardDealer = [[Dealer alloc] init];

		NSArray *array = @[spot, drum, cardDealer];
		NSUInteger index = arc4random_uniform(3);
		id item = [array objectAtIndex:index];
		[item play];
	}
	return 0;
}

NSMutableArray *attendance = [NSMutableArray arrayWithArray: @[@”Diego”]];
[attendance addObject:@”Rahul”]

NSArray *invited = @[@”Diego”, @”Rahul”, @”Elana”]

Differences:Handling Nil

Objective-C: Any object can be nil
Swift: Optionals can be nil

#import <Foundation/Foundation.h>
#import "Messengaer.h"
#import "Package.h"

int main(int argc, const char * argv[]){
	@autoreleasepool {

		Messenger +spike = [[Messenger alloc] init];
		Package *importantDocuments = [spike pickUpPackage];

		NSLog(@"package contents: %@", importantDocuments.contents);
	}
	return 0;
}

Objective-C and Swift approaches to mutability differ
– how mutability is achieved for a given type
– the probability of an unintended mutation propagating through a program

#import <Foundation/Foundation.h>
#import "Messengaer.h"
#import "Package.h"

int main(int argc, const char * argv[]){
	@autoreleasepool {

		NSArray *kayakingGear = [NSMutableArray arrayWithArray:@[@"halmet",@"paddle",@"boat",
			@"lifejacket"]];
			[kayakingGear addObject:@"booties"];

			NSLog(@"%@", kayakingGear);
	}
	return 0;
}

Design pattern

Protocols Enable Shared Functionality Across Classes
pets, dogs, birds, flight, bats, insects

UITextFieldDelegateProtocol in Swift

func textField(textField: UITextField,
	shouldChangeCharactersInRange range:NSRange,
		replacementString string: String) -> Bool {
	
		var newText = textField.text! as NSString
		newText =
		newText.stringByReplacingCharactersInRange(range,
			withString: string)

		return newText.length <= 5
}

UITextFieldDelegateProtocol in Objective-C

-(BOOL)textField:(UITextField *)textField
	shouldChangeCharactersInRange:(NSRange)range
		replacementString:(NSString *)string{

		NSString *nexText = textField.text;
		newText = [newText
		stringByReplacingCharactersInRange:range
			withString:string];

		return (newText.length <=5);
}

Objective-C

Objective-C: Any object can be nil, dynamic typing
Swift: Optionals can be nil, limited mutability
iOS Frameworks Design-Patterns: static typing

// Swift
override func viewWillAppear(animated: Bool){
	super.viewWillAppear(animated)
	displayResult()
}

// Objective-C
- (void)viewWillAppear:(BOOL) animated {
	[super viewWillAppear:animated];
	[self displayResult];
}

AppDelegate Methods

func application(application: UIApplication, didFinishLaunchingWithOptions
	launchOptions: [NSObject: AnyObject]?) -> Bool {
	return true
}
func applicationWillResignActive(application: UIApplication){
}
func applicationDidEnterBackground(application: UIApplication){
}
func applicationWillEnterForeground(application: UIApplication){
}
-(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:
	(NSDictionary *)launchOptions {
	return YES;
}

- (void)applicationWillResignActive:(UIApplication *)application{
}

- (void)applicationDidEnterBackground:(UIApplication *)application {
}

- (void)applicationWillEnterForeground:(UIApplication *)application {
}

Loading and showing interstitial AD

Interstitial Ad – AdListener
loadAd -> onAdLoaded -> show, isLoaded

public class InterstitialActivity extends Activity {
	private Button mShowButton;
	private InterstitialAd mInterstitial;

	@Override
	public void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_interstitial);

		mShowButton = (Button) findViewById(R.id.showButton);
		mShowButton.setEnabled(false);
	}

	public void loadInterstitial(View unusedView){
		mShowButton.setEnabled(false);
		mShowButton.setText("Loading Interstitial");

		mInterstitial = new InterstitialAd(this);
		mInterstitial.setAdUnitId("ca-app-pub-xxxx/xxxx");
		mInterstitial.astAdListener(new ToastAdListener(this){
			@Override
			public void onAdLoaded(){
				super.onAdLoaded();
				mShowButton.setText("Show Interstitial");
				mShowButton.setEnabled(true);
			}
			@Override
			public void onAdFailedToLoad(int errorCode){
				super.onAdFailedToLoad(errorCode);
				mShowButton.setText(getErrorReason());
			}
			});
			AdRequest.on = new AdRequest.Builder().build();
			mInterstitial.loadAd(ar);
		}

	public void showInterstitial(view unusedView){
		if (mInterstitial.isLoaded()){
			mInterstitial.show();
		}
		mShowButton.setText("Interstitial Not Ready");
		mShowButton.setEnabled(false);
	}
}

loadInterstitial
-Create InterstitialAd
-Set AdUnit Id
-Create Listener – onAdLoaded – show, onAdFailedToLoad – error
-Create AdRequest & LiadAd