ios developer overview - devweek 2014

iOS Application Development

iOS Developer OverviewPaul Ardeleanu

Assumptions…

You are:‣ a developer of sorts…

‣ have no or little exposure to iOS

‣ want to learn enough to become ‘dangerous’

The plan

‣ Why iOS?

‣ Tools

‣ Storyboarding

‣ Objective-C

‣ Design patterns

‣ Debug & Testing

‣ Ad-Hoc distribution

‣ Publishing in the app store


Why iOS?


Once upon a time…

… there were phoneshttp://www.flickr.com/photos/adrianblack/371301544/

Then the iPhone happened…

Before & after

https://twitter.com/JoshHelfferich

App Store

Global Phone Market Units shipped / quarter

© Asymco - used with permission

Smartphone shipments



Developer tools

iOS Simulator

Instruments

CocoaPods.org

Reveal

Documentation


Building great apps

Building great apps

‣ Constraints‣ small size

‣ limited hardware

‣ one screen at a time

‣ one application at a time *

‣ touch input

‣ Interaction‣ gestures

‣ shake

‣ orientation

‣ audio switch, volume buttons

‣ home & power buttons

List of features

too manyfeatures?

Filter

Yes

ApplicationDefinitionStatement

Appfeatures

User journeys

Wirefames

Prototype

Application Definition Statement

“A concise, concrete declaration of the app’s main purpose and its intended audience.”

https://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/MobileHIG/

Solve real problems

"An app must solve a user's problem clearly and elegantly."

Eric Hope, User Experience Evangelist, Apple

Delivery channels

‣ web app [dedicated]

‣ native app

‣ “hybrid” solutions


Storyboarding

What is Storyboarding

‣ Design the “screens” that compose your app => scenes

‣ Visually define the navigation between the scenes => segues

‣ Introduced in: iOS 5 & Xcode 4.2

Xcode 5 - default

Xcode 4 - optional

Main Storyboard

A simple app

Specialised View Controllers

‣ UITableViewController

‣ UINavigationController

‣ UITabBarController

‣ UICollectionView

UITableViewController

UINavigationController

UITabBarController

UIToolbar

UICollectionView

iOS 6 & 7

iPhone 3.5 vs 4-inch


Objective-C

What is Objective C

‣ Thin layer on top of C; strict superset of C

‣ Object-oriented programming language

‣ Inspired by SmallTalk

‣ Developed by Stepstone / NeXT Software / Apple

‣ The development language for Mac OSX & iOS devices

Object-Oriented Programminga programming paradigm that uses "objects"

!myCar

• Number of wheels

• Number of seats

• Colour

• Engine size

• Top speed

• Drive

• Brake

• Turn Left

• Beep

• Fill with petrol

MethodsProperties

Data + Behaviour

Vehicle classInterface .h Implementation .m

Vehicle.h Vehicle.m

@interface Vehicle { int wheels; int seats; } !-‐ (void)drive; -‐ (void)setWheels:(int)n; !@end

#import "Vehicle.h" !@implementation Vehicle !-‐ (void)setWheels:(int)n { wheels = n; } !-‐ (void)drive { … } !@end

Methods syntax

-‐ (void)setWheels:(int)n;

return type name argument typeargument name

type

Multiple arguments

-‐ (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

application:didFinishLaunchingWithOptions:

The name of the method is:

Multiple arguments

+ (void)animateWithDuration:(NSTimeInterval)duration delay:(NSTimeInterval)delay options:(UIViewAnimationOptions)options animations:(void (^)(void))animations completion:(void (^)(BOOL finished))completion;

+ (void)animateWithDuration:(NSTimeInterval)duration animations:(void (^)(void))animations;

Multiple arguments

[UIView animateWithDuration:1.0 delay:0.3 options:UIViewAnimationOptionCurveEaseIn animations:^{ // animations } completion:^(BOOL finished) { // completion block } ];

+ (void)animateWithDuration:(NSTimeInterval)duration delay:(NSTimeInterval)delay options:(UIViewAnimationOptions)options animations:(void (^)(void))animations completion:(void (^)(BOOL finished))completion;

Properties

@implementation Vehicle !-‐ (int)wheels { return wheels; } !-‐ (void)setWheels:(int)n { wheels = n; } !@end

@interface Vehicle : NSObject { int wheels; } !-‐ (int)wheels; -‐ (void)setWheels:(int)n; !@end

@implementation Vehicle !!!@end

@interface Vehicle : NSObject { !} !@property int noWheels; !@end

int numberWheels;

@synthesize numberWheels;

Properties & dot notation

Vehicle *myCar = [Vehicle new]; !myCar.wheels = 5; !myCar.wheels

What is a method?

typedef struct objc_selector *SEL;

!Vehicle *myCar = [Vehicle new]; ![myCar drive];

objc_msgSend(myCar, @selector(drive))

Sending a message

-‐ (void)setWheels: (int)n;

[myCar setWheels:4];

objc_msgSend(myCar, @selector(setWheels:), 4);

Sending a message!Vehicle *myCar = nil; ![myCar drive];

myCar = ...; if ([myCar respondsToSelector:@selector(drive)]) { [myCar drive]; }

InitialisersVehicle *myCar = [Vehicle new];

-‐ (id)initWithWheels:(int)wheels { self = [super init]; if (nil != self) { // Custom initialization self.wheels = wheels; } return self; }

Vehicle *myCar = [[Vehicle alloc] initWithWheels:4];

Vehicle *myCar = [[Vehicle alloc] init];

InitialisersMultiple

@interface Vehicle : NSObject !@property int wheels; @property int seats; !-‐ (id)initWithWheels:(int)wheels andSeats:(int)seats; -‐ (id)initWithWheels:(int)wheels; -‐ (id)initWithSeats:(int)seats; !@end

InitialisersMultiple

-‐ (id)init { return [self initWithWheels:DefaultNumberWheels andSeats:DefaultNumberSeats]; }

#define DefaultNumberWheels 4 #define DefaultNumberSeats 5

-‐ (id)initWithWheels:(int)wheels andSeats:(int)seats{ self = [super init]; if (nil != self) {

self.wheels = wheels; self.seats = seats;

} return self; }

-‐ (id)initWithWheels:(int)wheels { return [self initWithWheels:wheels andSeats: ]; }

-‐ (id)initWithNumberSeats:(int)seats { return [self initWithWheels:DefaultNumberWheels andSeats:seats]; }

DefaultNumberSeats

Inheritance

@interface Truck : Vehicle !!!!!!!!!!!@end

@interface Vehicle : NSObject !@property int wheels; @property int seats; !-‐ (void)drive; !@end -‐ (void)checkLoad;

-‐ (void)loadWithWeight:(int)weight; -‐ (void)unload;

{ int maxWeight; }

@property int currentWeight;

InheritanceNSObject

NSPredicateNSArray

NSComparisonPredicateNSMutableArray

UIResponder

UIView

UIWindow UIControl

UIButton

UIGestureRecognizer

UIApplicationNSNumber

NSValue

instance

class

isa

superclass

superclass

metaclassisa

metaclassisa

superclass

NSObject

superclass

superclass

nil

metaclassisa

superclass

superclass

Polymorphism & Dynamic typing

Vehicle

Truck !

- (void)drive

Car !

- (void)drive

id aVehicle; !... ![aVehicle drive];

id‣ the generic object type

‣ can be used for object of any type

‣ the object class is determined at runtime (dynamic typing)

Vehicle *aCar;

Static typing

id aCar;

Dynamic typing

Introspection

NSObject

- (BOOL)isKindOfClass:(Class)aClass; - (BOOL)isMemberOfClass:(Class)aClass;

- (Class)superclass; - (Class)class;

- (BOOL)respondsToSelector:(SEL)aSelector;

Protocols

-‐ (void)load; -‐ (void)unload; -‐ (float)getWeight;

@interface Truck : Vehicle

@end

Protocols


@implementation Truck !!!!!!!!!!!!!@end

-‐ (void)load { ... } -‐ (void)unload { ... } -‐ (float)getWeight { ... }


@end

Protocols



@end

@protocol VehicleLoading

@end

<VehicleLoading>

Protocols



@end

@protocol VehicleLoading

@end

<VehicleLoading>

@implementation Truck !!!!!!!!!!!!!@end

-‐ (void)load { ... } -‐ (void)unload { ... } -‐ (float)getWeight { ... }

Category

@interface Vehicle : NSObject !... !-‐ (void)drive; -‐ (void)brake; !@end

!Vehicle *myCar = [Vehicle new];

[myCar steerLeft];

Category

@interface NSString : NSObject !!!!!!@end

@interface NSString : NSObject !!!!!!@end

Category

- (NSUInteger)wordCount;

Category

#import "NSString.h" !@interface NSString (H24Utils) !-‐ (NSUInteger)wordCount; !@end

NSString+H24Utils.h NSString+H24Utils.m

Category

#import "NSString.h" !@interface NSString (H24Utils) !-‐ (NSUInteger)wordCount; !@end

NSString+H24Utils.h NSString+H24Utils.m

#import "NSString+H24Utils.h" !@implementation NSString (H24Utils) !-‐ (NSUInteger)wordCount { … } !@end

Naming conventions

Classes

Objects

camelCase with capitalised first letter (a.k.a. Pascal case)

Prefixes

HelloWorldViewController

camelCaseviewController, myCar

NSArray, UIView

BOOL data type

typedef signed char BOOL; !#define YES (BOOL)1 #define NO (BOOL)0

Blocks

void (^sayHello)(NSString *) = ^(NSString *name) { NSLog(@“Hello %@", name); };

NSString *sayHello = @"Hello World";

Blocks

void (^sayHello)(NSString *); !sayHello = ^(NSString *name) { NSLog(@"Hello %@", name); };


Blocks@interface Person : NSObject !@property NSString *name; !-‐ (void)welcomeUserWithBlock:(void (^)(NSString *))theBlock; !@end

@implementation Person !… !-‐ (void)welcomeUserWithBlock:(void (^)(NSString *))theBlock { theBlock(self.name); } !@end

Blocks


Person *theUser = [[Person alloc] initWithName:@"Paul"];

[theUser welcomeUserWithBlock:^(NSString *name) { NSLog(@"Hello %@", name); }];

[theUser welcomeUserWithBlock:sayHello];

Blocks

Person *theUser = [[Person alloc] initWithName:@"Paul"];

[theUser welcomeUserWithBlock:^(NSString *name) { NSLog(@"Hello %@", name); }];

Block scope

!!Person *theUser = [[Person alloc] initWithName:@"Paul"]; ![theUser welcomeUserWithBlock:^(NSString *name) { NSLog(@"Hello %@", name); }];

message

Module09_02[8635:303] Hello Paul

NSString *message = @"Hello %@";

Block scopeNSString *message = @"Hello %@"; !!!!!!Person *theUser = [[Person alloc] initWithName:@"Paul"]; ![theUser welcomeUserWithBlock:^(NSString *name) { NSLog(@"Hello %@", name); }];

message

... !if (morning) { message = @"Good morning %@"; }

Module09_02[8693:303] Good morning Paul

Example

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Hello" message:@"Are you sure?" delegate:self cancelButtonTitle:@"No" otherButtonTitles:@"Yes", nil]; [alert show];

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex { ... }

Example

@interface UIAlertView (H24Blocks) !!+ (UIAlertView*) alertViewWithTitle:(NSString*) title message:(NSString*) message cancelButtonTitle:(NSString*) cancelButtonTitle otherButtonTitles:(NSArray*) otherButtons onDismiss:(IndexBlock) dismissed onCancel:(EmptyBlock) cancelled; !@end

Example

[UIAlertView alertViewWithTitle:@"Hello" message:@"Hello World" cancelButtonTitle:@"Cancel" otherButtonTitles:@[@"OK"] onDismiss:^(int buttonIndex) { NSLog(@"Dismissed"); } onCancel:^{ NSLog(@"Cancelled"); }];


Design Patterns

Design Patterns

‣ Accessors Pattern‣ allows access to an object properties through simple methods

‣Anonymous Type Pattern‣ send message to objects of an uncertain (at compilation) type

‣2-stage Object Creation Pattern‣ alloc + init = new‣ allow custom initialisers

‣Outlets, targets & actions‣ configuration of and interaction with UI elements

MVC

Model

View Controller

MV[C]

Model

View Controller

[M]VC

Model

View Controller

[M]VC

Model

View Controller !View

Controller

Decorator pattern

‣ add bevaviour to an object

‣ without affecting the behaviour of other objects from the same class

Categories

‣ adds functionality to classes without the need to subclass

‣ group common methods and implement them across the relevant framework

‣ informal protocols (unimplemented methods)

‣ anonymous category (private methods)

Delegation

‣ a delegate is an object that works together with its delegator to solve a problem

‣ a delegate adds/changes the behaviour of the delegator (avoids subclassing)

‣ loose coupling

‣ a delegate is usually referenced using the anonymous type

@interface MyAppDelegate : NSObject <UIApplicationDelegate>

Observer pattern

‣ enables communication between objects

‣ no coupling

‣ one object notifies another object (registered as ‘listener’) when a change occurs

Notifications

‣ an object registers as observer

‣ when a notification is sent to the Notification Center, it is distributed to all listeners

[NSNotificationCenter defaultCenter]

Notifications

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(soSomething)

name:@"H24CourseNotification" object:nil];

[[NSNotificationCenter defaultCenter] postNotificationName:@"H24CourseNotification" object:nil];

[[NSNotificationCenter defaultCenter] removeObserver:self];

Key-Value Observing

‣ KVC - Key Value Coding

‣ KVO - Key Value Observing

KVC@interface Vehicle : NSObject

@end


@end

@property NSString *maker;


@end

myCar.maker [myCar maker]

myCar.maker = @"Ford"; [myCar setMaker:@"Ford"];



@end

[myCar valueForKey:@"maker"]; [myCar setValue:@"Ford" forKey:@"maker"];





@end

@property User *owner;






@end

@property User *owner;

[myCar valueForKeyPath:@"owner.firstName"] [myCar setValue:@"John" forKeyPath:@"owner.firstName"];





KVO

[aVehicle addObserver:self forKeyPath:@"owner" options:NSKeyValueObservingOptionNew context:nil];

options:(NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld)

KVO

- (void)observeValueForKeyPath:(NSString *)keyPath " ofObject:(id)object " change:(NSDictionary *)change " context:(void *)context

KVO

[vehicle removeObserver:self forKeyPath:@"owner"];

Key-Value Observing

‣ KVC - Key Value Coding

‣ KVO - Key Value Observing

Facade pattern

‣ simplified interface to a larger body of code

‣ subsystems accessed through a well defined entry point

‣ allows subsystems to change without affecting the overall functionality

UIImage+ (UIImage *)imageWithContentsOfFile:(NSString *)path

+ (UIImage *)imageNamed:(NSString *)name

Anatomy of an app

#import <UIKit/UIKit.h> !#import "AppDelegate.h" !int main(int argc, char * argv[]) { @autoreleasepool { return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class])); } }

main.m


App states

Slide Hello24 Ltd. (c) 2014

App states

122

Active

Inactive

Running

Suspende

Running

Not running

Background


No background

123


App life cycle

124

Active

Inactive

Running

Suspended

iPhone OS 3 iOS 4

Running

Not running

Running

Not running

Background


AppDelegate callbacks

‣ application:willFinishLaunchingWithOptions:

‣ application:didFinishLaunchingWithOptions:

‣ applicationDidBecomeActive:

‣ applicationWillResignActive:

‣ applicationDidEnterBackground:

‣ applicationWillEnterForeground:

‣ applicationWillTerminate:

125


Foreground

Background

Not running

App life cycle

126

Active

Inactive

Running

Suspended


App life cycle - app start

127

ForegroundActive

Inactive

BackgroundRunning

Suspended

Not running

1


Foreground

Background

Not running

App life cycle

128

Active

Inactive

Running

Suspended

willFinishLaunchingWithOptions:

1


Foreground

Background

Not running

App life cycle

129

Active

Inactive

Running

Suspended

2


1


Foreground

Background

Not running

App life cycle

130

Active

Inactive

Running

Suspended

2


1

didFinishLaunchingWithOptions:


Foreground

Background

Not running

App life cycle

131

Active

Inactive

Running

Suspended

2


1

didFinishLaunchingWithOptions:

applicationDidBecomeActive:


Foreground

Background

Not running

App life cycle - inactive

132

Active

Inactive

Running

Suspended


Foreground

Background

Not running

App life cycle

133

Active

Inactive

Running

Suspended


Foreground

Background

Not running

App life cycle

134

Active

Inactive

Running

Suspended

applicationDidResignActive:


Foreground

Background

Not running

App life cycle

135

Active

Inactive

Running

Suspended



Foreground

Background

Not running

App life cycle

136

Active

Inactive

Running

Suspended




Foreground

Background

Not running

App life cycle - background

137

Active

Inactive

Running

Suspended


Foreground

Background

Not running

App life cycle

138

Active

Inactive

Running

Suspended

1


Foreground

Background

Not running

App life cycle

139

Active

Inactive

Running

Suspended

1



Foreground

Background

Not running

App life cycle

140

Active

Inactive

Running

Suspended

1


2


Foreground

Background

Not running

App life cycle

141

Active

Inactive

Running

Suspended

1


2

applicationDidEnterBackground:


Foreground

Background

Not running

App life cycle

142

Active

Inactive

Running

Suspended

1


2

applicationDidEnterBackground:7


Foreground

Background

Not running

App life cycle

143

Active

Inactive

Running

Suspended

1


2

applicationDidEnterBackground:7 8


Foreground

Background

Not running

App life cycle

144

Active

Inactive

Running

Suspended

1


2


9


Foreground

Background

Not running

App life cycle

145

Active

Inactive

Running

Suspended

1


2


9

applicationDidEnterForeground:


Foreground

Background

Not running

App life cycle

146

Active

Inactive

Running

Suspended

1


2


9

10



Foreground

Background

Not running

App life cycle

147

Active

Inactive

Running

Suspended

1


2


9

10




Foreground

Background

Not running

App life cycle - terminate

148

Active

Inactive

Running

Suspended


Foreground

Background

Not running

App life cycle

149

Active

Inactive

Running

Suspended


Foreground

Background

Not running

App life cycle

150

Active

Inactive

Running

Suspended


Foreground

Background

Not running

App life cycle

151

Active

Inactive

Running

Suspended

applicationWillTerminate:


Debug & Testing

Instruments

Instruments - Leaks

Instruments - Allocations

Instruments - Zombies

Instruments - Time Profiler

Instruments

Network Link Conditioner

Network Link Conditioner on device

Pony Debugger

Pony Debugger

[16:04:17] paul@Pro2x:project1 [502] $ ponyd serve --listen-interface=127.0.0.1PonyGateway starting. Listening on 127.0.0.1:9000

[17:14:22] paul@Pro2x:MyPony [516] $ pod installSetting up CocoaPods master repoSetup completed (read-only access)Analyzing dependenciesDownloading dependenciesInstalling PonyDebugger (0.3.1)Installing SocketRocket (0.3.1-beta2)Generating Pods projectIntegrating client project![!] From now on use `MyPony.xcworkspace`.[deprecated] I18n.enforce_available_locales will default to true in the future. If you really want to skip validation of your locale you can set I18n.enforce_available_locales = false to avoid this message.

Pony Debugger

PDDebugger *debugger = [PDDebugger defaultInstance]; [debugger connectToURL:[NSURL URLWithString:@"ws://127.0.0.1:9000/device"]]; [debugger forwardAllNetworkTraffic]; [debugger enableCoreDataDebugging]; [debugger addManagedObjectContext:self.managedObjectContext withName:@"MyPony"]; [debugger enableViewHierarchyDebugging]; [debugger enableRemoteLogging];

Pony Debugger

Reveal


Ad-Hoc distribution

TestFlight

HockeyApp


Publishing

iTunes Connect

New App

Pricing Matrix

ios developer overview - devweek 2014

Technology

ios simulator

h vehicle

launchoptions application

initialisers vehicle

mycardrive mycar

intwheels voidsetwheels

development language

vehicle alloc initwithwheels