Mobile Applications and Services FALL 2013 · Mobile Applications and Services FALL 2013 - iOS...

Navid Nikaein

Mobile Communication Department

Mobile Applications and Services FALL 2013

- iOS basics

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What do you need?

Mac OS X 10.5 or above

Notions on OO programming (Objective C)

iOS SDK (Free, registration required)

iOS Dev License (Optional) Student Program: Free Individual Program: $99 Enterprise Program: $399

An iPhone/iPod Touch/iPad (Optional)

©Navid Nikaein 2013 2

htpp://www.eurecom.fr/

iOS Smart Mobile Devices

iOS 7 Multi Touch Display (1.136x640) Storage 8-64 GB Processor M7 /A7 64 bits, A6, A5 Graphics Power VR Memory 1GB DDR2 Connectivity

USB 2.0 GSM/GPRS/EDGE/UMTS/HSDPA/LTE Wifi 802.11 b/g/n BT Assisted GPS

Double Camera: 8 MP & 1.2MP HD Audio/VIDEO Power 3.8 V Weight 112g


Primary Applications

Secondary Applications


Platform Components

iOS SDK / Tools

Language

Frameworks

Design Strategies



Platform Component - iOS SDK

Tools: Xcode

Text editor, Debugger & Compiler

Interface Builder (UI) storyborad Creates user interface (xml)

Instruments (profiler ) Optimize the application

Dash Code Create web applications for Safari

iOS Simulator (Code-Build-Debug) Dtrace, NSZombies, Guard Mallloc

Reference Library


.xib

.m, .h .nib


Xcode



App Development Process

Who are your audience ? What is the purpose of your app? What problem your app trying to solve? What content your app incorporate?



Next step

After you have a concept for your app, designing a good user interface is the next step to creating a successful app Storyboard, views ,… Define the interaction Implementing the behaviours



Platform Component - iOS Language

Objective-C / C Extension to (superset of) standard ANSI C with Smalltalk-style messaging

designed to give C full OO programming capabilities Primary language for Apple’s Cocoa API C & GCC can be used for low-level programming



A big Picture



Platform Component - iOS Frameworks Name Prefixes

Accelerate.framework cblas, vDSP

AddressBook.framework AB

AddressBookUI.framework AB

AssetsLibrary.framework AL

AudioToolbox.framework AU,Audio

AudioUnit.framework AU

AVFoundation.framework AV

CFNetwork.framework CF

CoreAudio.framework Audio

CoreData.framework NS

CoreFoundation.framework CF

CoreGraphics.framework CG

CoreLocation.framework CL

CoreMedia.framework CM

CoreMotion.framework CM

CoreTelephony.framework CT

CoreText.framework CT

CoreVideo.framework CV

EventKit.framework EK


Name Prefixes

EventKitUI.framework EK

ExternalAccessory.framework EA

Foundation.framework NS

GameKit.framework GK

iAd.framework AD

ImageIO.framework CG

IOKit.framework N/A

MapKit.framework MK

MediaPlayer.framework MP

MessageUI.framework MF

MobileCoreServices.framework UT

OpenAL.framework AL

OpenGLES.framework EAGL, GL

QuartzCore.framework CA

QuickLook.framework QL

Security.framework CSSM, Sec

StoreKit.framework SK

SystemConfiguration.framework SC

UIKit.framework UI


iOS Frameworks: New


Name Prefixes

Account.framework AC

CoreBluetooth.framework CB

CoreImage.framework CI

Core.MIDI.framework MIDI

GLKit.framework GLK

GSS.framework gss

Twiter.framework TW

See appendix B of iOS Technology Overview


frameworks



iOS Design Patterns and Techniques

Model-view-controller design pattern that governs the overall structure of your app

Delegation Transfer information and data from one object to another

Target-Action Translates user interactions with buttons and controls into code

that your app can execute

Block-Objects Implement callbacks and asynchronous code

Sandboxing Protect the system and other apps



Platform Component - iOS Design Strategy

Cocoa version of Model-View-Controller (MVC) Assigns objects in an application one of three roles: model, view, or controller Defines the way objects communicate with each other Separate and allow generic view and models Controllers acts as a glue between view and model

MVC allows reusability and flexibility to your application


Encapsulate, manipulate, and process the data specific to an application

How your model is presented/viewed to the user (UI logic)

knows how to draw itself and can respond to user actions


MVC

All about managing the communication between objects



MVCs working together



MVC

Model = manipulate and process data / algorithm / networking Not aware of controller and view To-one and to-many relationship with other model objects Communicate generically using broadcast channel

Key-value observing (listen to changes) Notification (NSNotificationCenter)

Communication example User actions in the view layer that create or modify data are

communicated through a controller object and result in the creation or updating of a model object.

When a model object changes (for example, new data is received over a network connection), it notifies a controller object, which updates the appropriate view objects



MVC

View = Display / Event capture / Visual interaction Not aware of controller and model Know how to draw itself and user can interact with it Generic and provides consistency between applications Communicate generically using

Target – Action Delegate (Will, did, should)

Communication example View objects learn about changes in model data through the

application’s controller objects User-initiated changes—for example, text entered in a text field—

through controller objects to an application’s model objects.



MVC

Controller = coordination / delegation / dirty job Know about view and model objects Manage views, datas, and application logic and lifecycle App –specific code Communication:

A controller object interprets user actions made in view objects and communicates new or changed data to the model layer.

When model objects change, a controller object communicates that new model data to the view objects so that they can display it.



Application Object and Delegation

Application template comes with a few existing source code files that set up the app environment. UIApplicationMain function creates the app object to work with iOS

create a run loop to deliver events to your app coordinates other high-level app behaviors

Called by main.m

UIApplicationMain creates two components Application object: an instance of UIApplication App Delegate

Window: creates and keep track of the window where your app’s content is drawn

Lifecycle: provides a place to respond to state transitions within the app:



Target-Action

Action Piece of code that’s linked to some kind of event that can occur in your app creating and implementing a method with an IBAction return type and a sender

parameter - (IBAction)restoreDefaults:(id)sender;

Sender points to the object that triggers the action

Outlet provide a way to reference objects from your interface

@property (weak, nonatomic) IBOutlet UITextField *textField;

Control Event provide a way for your code to receive messages from the user interface

Touch and drag events Editing events Value-changed events

Navigation controller Manage the transition between the views Navigation stack is LIFO, and the first item is always root view controller



Sandbox

Fine-grained controls that limit the app’s access Hone of the app

App and its preferences and data are placed in sandbox at the install time



Core Objects of an App


Image View

Text View

Button


App States

Not running app has not been launched or was

running but was terminated by the system

Inactive running in the foreground but is

currently not receiving events

Active running in the foreground and is

receiving events

Background Background and executing code

Before being suspended Background directly

Suspended Background and not executing code



State Transitions

application:willFinishLaunchingWithOptions first chance to execute code at launch time.

application:didFinishLaunchingWithOptions perform any final initialization before your app is displayed to the user.

applicationDidBecomeActive Lets your app know that it is about to become the foreground app. Use this method for any last

minute preparation.

applicationWillResignActive Lets you know that your app is transitioning away from being the foreground app. Use this method

to put your app into a quiescent state.

applicationDidEnterBackground: Lets you know that your app is now running in the background and may be suspended at any time.

applicationWillEnterForeground Lets you know that your app is moving out of the background and back into the foreground, but

that it is not yet active.

applicationWillTerminate Lets you know that your app is being terminated. This method is not called if your app is

suspended.



App Launch Cycle



iOS Architecture

iOS can be viewed as a set of layers


HW


iOS Features

Cocoa touch UIkit Multitouch gestures Storyborad Document , printing

Networking Services Store Kit (in-app) Push notification Game Kit iAd Core location Map Kit Networking (BSD Socket) Accelerate


Media Graphics Audio Camera & photo lib iPod media lib

Core services iOS simulator Inter-app messaging Messaging In-app SMS Cut, copy, paste Gyro + accelerometer Multitasking Addressbook Compass Accessories Quicklook


iOS – Core OS

Low level interface for operating system (kernel environment and drivers) Accelerate Framework Core Bluetooth External Accessory Framework Security Framework

Lib System Library Threading (POSIX threads) Networking (BSD sockets) File-system access Standard I/O Bonjour and DNS services Locale information Memory allocation Math Computation

Core OS

Core Service

Media

Cocoa Touch

iOS



iOS – Core Service

Fundamental system services for applications Account Framework Address Book Framework Core Foundation Framework CFNetwork Framework Core Data Framework Core Location Framework Core Media Framework (low-level) Core Telephony Framework Event Kit Framework Foundation Framework Mobile Core Service Framework Newsstand Kit Framework Quick Look Framework Store Kit Framework System Configuration Framework

Core OS

Core Service

Media

Cocoa Touch

iOS



iOS – Core Service

CF Network Framework BSD sockets Encrypted

connections(SSL / TLS ) Resolve DNS hosts Work with HTTP,

authenticating HTTP, HTTPS , FTP servers

Publish, resolve, and browse

Bonjour services

Core Data Framework SQLite lib Manage and edit data Validation and data

consistency Support for grouping,

filtering, and organizing data in memory

Core OS

Core Service

Media

Cocoa Touch

iOS


Foundation Framework Collection data types Bundles Date and time

management Raw data block

management Preferences

management URL and stream

manipulation Threads and run loops Bonjour Communication port

management Internationalization Regular expression

matching Cache support


iOS – Media

Technologies for creating multimedia experience Assets Library Framework (retrieving photo/video) AV Foundation Framework Core Audio

Core audio Framework Audio toolbox Framework Audio unit Framework

Core Graphic Frameworks (Quartz 2D) Core Image framework Core MIDI framework Core Text Framework Core Video Framework Image I/O Framework GL Kit framework Media Player Framework Open AL Framework OpenGL ES (3D audio for game) Quartz Core Framework

Core OS

Core Service

Media

Cocoa Touch

iOS



iOS – Media

AV Foundation Framework Media asset management Media editing Movie capture Movie playback Track management Metadata management for media Stereophonic panning Synchronization between sounds An Objective-C interface for

determining details about sound files, such as the data format, sample rate, and number of channels

Core OS

Core Service

Media

Cocoa Touch

iOS



iOS – Cocoa Touch

Basic tools and infrastructure to implement graphical, event-driven applications in iOS Addressbook UI framework Addressbook framework Event Kit UI framework Game Kit framework iAd framework Map kit framework Message UI framework UIkit framework Twitter framework

Core OS

Core Service

Media

Cocoa Touch

iOS



iOS – Cocoa Touch

UI kit framework Application management User interface management Graphics and windowing support Multitasking support Support for handling touch and motion-based events Representing the standard system views and controls Support for text and web content Cut, copy, and paste support Support for animating user-interface content PDF creation Support for using custom input/text views that behave

like the system keyboard

Other supports Accelerometer data The built-in camera (where present) The user’s photo library Device name and model information Battery state information Proximity sensor information Remote-control information from attached headset

Core OS

Core Service

Media

Cocoa Touch

iOS



Styles of Programming

iOS defines three basic styles for applications: Productivity style Utility style Immersive style



Productivity Style

Organization and manipulation of detailed information Multiple screens and make use of system controls to handle the navigation from

screen to screen Typically rely on system views and controls (text fields, labels, and other data-

oriented views) for their presentation and do little or no custom drawing



Utility Style

Perform a specific task that requires relatively little user input A quick summary of information or a simple task on a small number of objects Interface should be a visually appealing and uncluttered to make it easier to spot the

needed information quickly Use of appropriate graphics to have a pleasing visual appearance



Immersive Application

Offer a full-screen, visually rich environment that’s focused on the content and the user’s experience with that content

Commonly used for implementing games and multimedia-centric applications Often present custom interfaces, and relies less on standard system views and

controls Typically use OpenGL ES to draw content, because it provides good performance for

full-screen content at high frame rates



OBJECTIVE-C



OO Vocabulary

Class Defines the grouping of data and code Create instances

Instance A specific allocation of a class

Method A “function” that an object knows how to perform

Instance Variable (or “ivar”) A specific piece of data belonging to an object


Object


OO Vocabulary - Classes, Instance, and Object

Classes declare state and behavior

State (data) is maintained using instance variables

Behavior is implemented using methods

Instance variables typically hidden Accessible only using getter/setter methods



OO Vocabulary

Encapsulation Restrict access to some of the

object’s components

Polymorphism Different vars / functions

/objects, same interface

Inheritance Hierarchical organization,

share code, customize or extend behaviors

Specific behavior

Generic behavior

Memory management NSObject

UIControl

UIBotton UITextField

Superclass

subclass



Objective-C

Invented in 1983 by Brad Cox and Tom Love after being introduced to Smalltalk. Released in 1986.

Is an object oriented language (like C++ or Java)

Follow ANSI C style coding with methods from Smalltalk

Almost everything is done at runtime! Dynamic binding : map msg from one object to another Dynamic typing : allow to capture/send msg to different obj Dynamic linking : load , links, and bind shared libs at run time



Files

.h – Header files contain class, type, function, and constant declarations

.m & .mm – Contains the implementation .m: c and objective-C .mm: c++, c, and objective-C

@interface Class : superClass {

// member definitions

}

// public method definition

@end

@implementation Class

// public & private methods

@end



A Quick Comparison

Java or C++ Syntax

Person* person = new Person();

int age = person.age();

person.setWeight(1.8);

person.setXandY(20.0f,1.0f);

delete person;

Objective-C Syntax

Person* person =[[Person alloc] init];

int age = [person age ];

[person setWeight:1.8];

[person setX:20.0f andY:1.0f];

[person release];



A Quick Comparison C++ Syntax (.h)

Typedef struct { Float x; Float y;

} Point; Class Car {

Point position; float velocity; Int model; Char* vin;

Public: static const int viper =1; Car (int m); ~car(); Point position(); Void setPosition (Point P); };

Objective-C Syntax (.h) Typedef struct {

Float x; Float y;

} Point; @interface Car : NSObject {

Point position; float velocity; Int model; NSString* vin;

} + (int) viper; -(id) initWithModel: (int)m; -(void) dealloc; -(Point) position; - (void) setPosition:(Point)p; @end



A Quick Comparison C++ Syntax (.cpp)

#include « Car.h»

Car::Car(int m) {

position.x=0.0f;

position.y=0.0f;

model = m;

Vin= « 295ZHGO45308 »

}

Car::~Car(){}

Point position () {return position};

Void setPosition (Point P) {

position =p;

}

Objective-C Syntax (.m) #import « Car.h» @implementation Car + (int) viper {return1}; - (id) initWithModel:(int)m { position.x=0.0f; position.y=0.0f; model = m; Vin= @« 295ZHGO45308 » } - (void) dealloc {[super dealloc]; } - (Point) position {return position}; - (void) setPosition:(Point)P{ position =p; } @end



Strong and Weak typing

Strong typing is when we use a class name to define a variable

Weak typing is when we use “id” as the type of the variable “id” can be anything

MyClass * class;

NSObject * theObject;

id sender;

id object;



Method definition

The following conventions are used in method declarations: A “+” precedes declarations of class methods A “-” precedes declarations of instance methods Argument and return types are declared using the C syntax

for typecasting Arguments are declared after colons(:)

The default return and argument type for methods is id

- (void)setWidth:(int)newWidth height:(int)newHeight



Calling methods

Two words with in a set of brackets, the object or class identifier and the method name

Calling methods in Objective-C is like sending messages Dynamic binding The connection in between the message and the receiver will be

done at runtime

[identifier method]



Class Methods

Equivalent to the “static” methods in C

The “alloc” method is an example:

To call the method we need to use a class

Automatic Reference counting (ARC)

[NSString alloc];

+(id)alloc;



Instance Methods

They can only be used on instances of objects

Contact * me;

[me getFullName];

@interface Contact : superClass

{

}

-(NSString *)getFullName;

@end



Member definition

Instance variables Members of the interface are defined in between the braces Usually we do not access them directly

@interface Contact {

NSString * name;

}

@end



Member definition

We can add properties for the different members using the keyword “property” Property: a combination of a getter and setter

Property declaration is equivalent to:

@interface Contact {

NSString * name;

}

@property (retain )NSString * name;

@end

- (NSString *)name; // getter

- (void)setName:(NSString *)newName; //setter



Declare properties

Properties are defined in the interface

They have to be “synthesized” in the implementation to be generated according to the property declaration

@property (attributes) type name;

@implementation Contact

@synthesize name;

@end



Declare properties

The properties can have a comma separated list of attributes.

The possible attributes are: getter=getterName setter=setterName readwrite / readonly assign retain copy nonatomic



Interface Builder -- > view

Members and methods can be connected with Interface Builder

Members are connected using the keyword “IBOutlet” in front of the type

Methods are connected using the keyword “IBAction” as return type

IBOutlet id button;

-(IBAction)buttonPressed;



Interface Builder

Interface Builder recognize actions using three prototypes:

We can connect objects and events from Interface Builder to the members and methods that we declare in Xcode

-(IBAction)actionName;

-(IBAction)actionName:(id)sender;

-(IBAction)actionName:(id)sender withEvent:(UIEvent *)event;



Inheritance

Only one inheritance at a time

All the members and public methods are inherited

@interface MyObject : NSObject {

}

@end



Protocols : multiple inheritance Protocols define a series of methods that classes, wanting to conform to it,

have to define a set of behavior that’s expected of an object in a given situation

A “protocol” is defined like an “interface” without implementation We use < > brackets to give a comma separated list of protocols

@protocol MyProtocol - (void) defineToBeConform; @end


@interface MyObject : NSObject<MyProtocol> { } @end


Delegates

Not really part of Objective-C

Intensively used in the iOS (cocoa touch)

A delegate is often a protocol

A delegate object is an object that acts on behalf of, or in coordination with, another object Often is a responder object responding to a user event

is delegated control of the user interface for that event, or is at least asked to interpret the event in an application

Example: UIAccelerometerDelegate

Original usage Refers to one object relying upon another to provide a specified set

of functionalities



Memory Management

iOS has a memory pool

Objects are reference counted

Two option: ARC enabled or disabled

The rule is: “We have to do a release for each alloc, create or copy that we use”

Note: the String in the example has to have the property attribute “retain” or the string will be destroyed by the pool.

NSString * aString = [[NSString alloc] init];

self.theString = aString;

[aString release];

@property (retain) NSString * theString;



5 Very Important References

developer.apple.com/library/ios iOS technology Overview iOS App Programming Guide Your First iOS App iOS App Development Workflow Guide Cocoa Fundamentals Guide Learning Objective-C: A Primer

Stanford course: iPhone application development http://www.stanford.edu/class/cs193p/cgi-bin/drupal/downloads-2011-

fall

developer.apple.com/technologies/ Developer tools iOS

Next Session Read NSObject and UIView documentation



Calling Methods

Calling method on an object

Method can return a value

Call method on classes, which is how you create an object.

id type means that the myObject variable can refer to any object id type is predefined as a pointer type


[object method]; [object methodWithInput:input];

output = [object methodWithOutput]; output = [object methodWithInputAndOutput:input];

id myObject = [NSString string]; NSString* myString = [NSString string];


Calling Methods

Nested message

Multi-input methods Method name is writeToFile:atomically: which is splited up

into several segments


[NSString stringWithFormat:[prefs format]];

-(BOOL)writeToFile:(NSString*)path atomically:(BOOL)useAuxiliaryFile; BOOL result = [myData writeToFile:@"/tmp/log.txt" atomically:NO];


Accessors

Use accessors to get and set values, as all instance variables are private by default Setter Getter [] is actually sending a message to an object or a class

Dot Syntax Only used for setters and getters and not for general purpose

methods


[photo setCaption:@"Day at the Beach"]; output = [photo caption];

photo.caption = @"Day at the Beach"; output = photo.caption;


Creating Objects

Automatic style

Manual style with nested methods Detail of init is unknown as a client of the class

Different version of init


NSString* myString = [NSString string];

NSString* myString = [[NSString alloc] init];

NSNumber* value = [[NSNumber alloc] initWithFloat:1.0];


Basic Memory Management

Garbage collector

Manual MM


// string1 will be released automatically NSString* string1 = [NSString string];

// must release this when done NSString* string2 = [[NSString alloc] init]; [string2 release];


Logging

Log in console

NSLog calls the description method on the object, and prints the NSString which is returned.

You can override the description method in your class to return a custom string


NSLog(@"The current date and time is:%@",[NSDate date]);


Calling Method on Nil

“nil” Object == Null Pointer in C

You call methods on “nil” without crashing or exceptions

Example: improving “dealloc” method

There's no chance of the variable pointing at random data where an object used to be


- (void) dealloc { * self.caption = nil; self.photographer = nil; [super dealloc]; }


OBJECTIVE-C THROUGH AN EXAMPLE



Walk Through Example



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