200810 - iPhone Tutorial

iPhone SDK a Ki k start
iPh SDK: Kick t t
Using Xcode 3.1 Developer Tools for iPhone OS

Copyright is held by the author/owner(s).
OOPSLA 2008, October 19–23, 2008, Nashville, Tennessee, USA.
ACM 978-1-60558-220-7/08/10.

Agenda

1.
1 Introduction
Apple Developer Connection, iPhone platform; Tools for development;.

2. Objective-C language
syntaxes; memory management; design patterns.

3. Creating a new project
simple “Hello World” example; simple drawing; multi touch events; configuration list
p p p g g

4. UI components
windows, views and view controllers; using Interface Builder.

5. iPhone in action
accelerometers; localization; media; openGL ES

6. Exercises and references

2

Our Objective

Using XCode 3.1 under Mac OS X 10.5 as our IDE, and Objective-C and iPhone API

as our programming t l we will create iPh
i tools ill t iPhone applications (f
li ti (from b i t medium
basic to di

level) which finally can be loaded into an iPhone. We’ll start with the classical “Hello

World” d
W ld” and continue t d
ti to develop applications using graphical user i t f
l li ti i hi l interfaces, handling
h dli

multi-touch and detect motion, communication with web application, and different

media.
di

3

Material

Google Groups :: OOPSLA08 iphone
G l G i h

http://groups.google.com/group/oopsla08-iphone
htt // l / / l 08 i h

4

Introduction
I t d ti
1.1.

What is it ?

iPhone is a pretty new device that involve several t h l i ( h
iPh i tt d i th t i l l technologies (phone, video,
id
audio, images, and web among others).

The best in 2007 year according to Times Magazine,

Big winner in the 2008 British Technology Awards. Claimed the award for Gadget of
the Year , won the Best Mobile Technology, Most Stylish Technology, and
Technological Innovation of the Year awards.

It has captive the interest of different types of users and created a new emerging
market in various environments. Today thousands of programmers want to provide
applications on the iPhone.

It includes multi touch interface, sensors and a camera.

6

Developer Connection

8

iPhone SDK

• Sample code
Documentation • Reference libraries
• Coding how-to

• UIKit
• Foundation
Frameworks • Media
• OpenGL / Quartz / Core Graphics
p p

• Xcode,
Tools • Interface Builder
• iPhone Simulator

9

Install

1. Boot into a partition with the Mac OS X v10.5.3 installed.

2. Download the iPhone SDK software.

3. Double-click on iPhone SDK installer package.

4. Follow the instructions in the Installer.

5. To i t ll Xcode 3.1 in directory other th th d f lt /D
5 T install X d 3 1 i a di t th than the default /Developer, you must specify a
l t if
new <Xcode> directory name on the "Custom Install" pane; e.g. Xcode3.1.

Select the folder icon under "Location" next to the "Developer Tools Essentials"
package name.
Select "Other..." at the top of the pop-up.
Navigate to the location for the new <Xcode> folder Select "New Folder".
folder. New Folder

10

Install

Enter folder
E t a f ld name i th "N
in the "New F ld " window; e.g. X d 3 1 S l t "C t "
Folder" i d Xcode3.1. Select "Create".
Finally, select "Choose" in the "Install Xcode Tools" pane.

6. If you need to install Mac OS X 10.3.9 Support or WebObjects, you must select
"Customize", and check those packages on the "Custom Install" panel.

7. Authenticate as the administrative user. The first user you create when setting up Mac
y g p
OS X has administrator privileges by default.

Developer applications such as Xcode, Instruments, and Interface Builder are

installed in <Xcode>/Applications.

11

Uninstall

To uninstall Xcode developer tools on the boot volume along with the <Xcode> directory from a
directory,
Terminal window type:

$ sudo <Xcode>/Library/uninstall-devtools --mode=all

If you just want to remove the underlying developer content on the boot volume, but leave the
<Xcode> directory and supporting files untouched, from a Terminal window type:

$ sudo <Xcode>/Library/uninstall-devtools --mode=systemsupport

If you just want to just remove the UNIX development support on the boot volume, but leave
the <Xcode> directory and supporting files untouched, from a Terminal window type:

$ sudo <Xcode>/Library/uninstall-devtools --mode=unixdev

Finally, to just uninstall the <Xcode> directory you can simply drag it to the trash, or from a
Terminal window type:

$ sudo <Xcode>/Library/uninstall-devtools --mode=xcodedir
<Xcode>/Library/uninstall devtools mode xcodedir

12

Time to Work 1
Install iPhone SDK

Tools for D
T l f Development
l t
1.2

Tools

We are going to be working with:

Xcode

Interface Builder

iPhone Simulator

And also need to consider

Instruments

15

Xcode

The f
Th focus of your development experiences is th X d application. X d i
f d l t i i the Xcode li ti Xcode is
an integrated development environment (IDE) that provides all of the tools you
need to create and manage your iPhone projects and source files, build your
code into an executable, and run and debug y
, g your code either in iPhone
simulator or on a device.

To create a new iPhone application, you start by creating a new project in
Xcode. A project manages all of the information associated with your
application, including the source files, build settings, and rules needed to put all
of the pieces t
f th i together. The heart of every Xcode project is th project windows.
th Th h t f X d j t i the j t i d

16

Xcode

editor,
Xcode comes with an advanced text editor which supports features such as code
completion, syntax coloring, code folding (to hide code blocks temporarily), and
inline annotations for errors, warnings, and notes. The build system in Xcode
provides both appropriate default settings and the ability to customize the
environment.
environment And if you need documentation the Research Assistant provides
documentation,
context-sensitive documentation while the Xcode documentation window lets you
browse and search for information.

When you build your application in Xcode, you have a choice of building it for
iPhone simulator or for a device. The simulator provides a local environment for
testing your applications to make sure they behave essentially the way you want.
After you are satisfied with your application’s basic behavior, you can tell Xcode to
build it and run it on an iPhone or iPod touch connected to your computer. Running
on a device provides the ultimate test environment, and Xcode lets you attach the
built-in debugger to the code running on the device.

18

Interface Builder

Interface Builder is the tool you use to assemble your application s user interface
application’s
visually. Using Interface Builder, you assemble your application’s window by
dragging and dropping preconfigured components onto it. The components include
standard system controls such as switches, text fields, and buttons, and also
custom views to represent the views your application provides. After you’ve placed
the
th components on the window’s surface, you can position th
t th i d ’ f iti them b d
by dragging th
i them
around, configure their attributes using the inspector, and establish the relationships
between those objects and your code. When your interface looks the way you want
it, you save the contents to a nib file, which is a custom resource file format.

The nib files you create in Interface Builder contain all the information that the UI Kit
needs to recreate the same objects in your application at runtime. Loading a nib file
creates runtime versions of all the objects stored in the file configuring them exactly
file,
as they were in Interface Builder. It also uses the connection information you
specified to establish connections between the newly created objects and any
existing objects in your application. These connections provide your code with
pointers to the nib-file objects and also provide the information the objects
themselves need t communicate user actions t your code.
th l d to i t ti to d

20

Interface Builder

21

Instruments

To ensure that you deliver the best user experience for your software the
software,
Instruments environment lets you analyze the performance of your iPhone
applications while running in the simulator or on a device. Instruments gathers data
from your running application and presents that data in a graphical display called
the timeline. You can gather data about your application’s memory usage, disk
activity, network activity, and graphics performance. Th ti li view can di l
ti it t k ti it d hi f The timeline i display
all of the different types of information side by side, letting you correlate the overall
behavior of your application, not just the behavior in one specific area. To get even
more detailed information, you can also view the detailed samples that Instruments
g
gathers.

In addition to providing the timeline view, Instruments provides tools to help you
analyze your application’s behavior over time For example the Instruments window
application s time. example,
lets you store data from multiple runs so that you can see whether your
application’s behavior is actually improving or whether it still needs work. You can
save the data from these runs in an Instruments document and open them at any
time.

22

Time to Work 2
XCode,
XC d IB and Instruments example
dI t t l

iPhone Pl tf
iPh Platform
1.3

Introduction

iPhone Pl tf
iPh Platform comprises th operating system and t h l i th t you use
i the ti t d technologies that
to run applications natively on iPhone and iPod touch devices and iPhone OS.

Although it shares a common heritage and many underlying technologies with
Mac OS X, iPhone OS was designed to meet the needs of a mobile
environment, where user’s needs are slightly different. Existing Mac OS X
developers will find many familiar technologies, but they’ll also find
technologies that are available only on iPhone OS such as the Multi-Touch
OS,
interface and accelerometer support.

27

Key Concepts

iPhone SDK supports the creation of graphically oriented applications that run
graphically-oriented
natively in iPhone OS.

Take advantage of built-in hardware such as the accelerometers, camera, and
graphics hardware
hardware.

All of the application’s data is displayed in a single window. This has lead to the
creation of new views and controls that allow you to present your application’s
data in an organized manner
manner.

The event-handling model in iPhone OS also represents a significant departure
from traditional desktop applications. Instead of relying on the traditional mouse
and keyboard events iPhone OS introduces the idea of touch events
events, events.

User experience.

Memory management without a “garbage collector”.
garbage collector

28

Architecture

Layers
L

Cocoa Touch

Media

Core Services

Core OS

29

Layers

Core OS and Core Services l
C dC S i layers contain th f d
t i the fundamental i t f
t l interfaces f
for
iPhone OS, including those used for accessing files, low-level data types,
Bonjour services, network sockets, and so on. These interfaces are mostly C
based and include technologies such as:
g

Core Foundation,
CFNetwork,
SQLite,
Access to POSIX threads,
UNIX sockets
Among others.

30

Layers

Media layer contains th f d
M di l t i the fundamental t h l i used t support 2D and 3D
t l technologies d to t d
drawing, audio, and video. This layer includes the C-based technologies:

OpenGL ES,
Quartz, and
Core Audio,
Core Animation, an advanced Objective-C based animation engine.

31

Layers

In the Cocoa Touch layer most of the technologies use Objective C The
layer, Objective-C.
frameworks at these layers provide the fundamental infrastructure used by your
application. For example:

the Foundation framework provides object-oriented support for collections,
file management, network operations, and more.

the UIKit framework provides the visual infrastructure for your application,
including classes for windows, views, controls, and the controllers that
manage those objects.

Other frameworks at this level give you access to the user’s contact and
photo information and to the accelerometers and other hardware features of
the device.

32

Starting Point

The t ti
Th starting point for any new project is the C
i tf j t i th Cocoa T
Touch l
h layer, and th UIKit
d the
framework in particular.

The higher-level frameworks make it easy to support standard system
behaviors with the least amount of effort on your part.

33

Objective-C Language
Obj ti C L
2

Objective-C
Objective C

The Objective-C language is a simple computer language designed to enable
Objective C
sophisticated object-oriented programming. Objective-C extends the standard ANSI
C language by providing syntax for defining classes, methods, and properties, as
well as other constructs that promote dynamic extension of classes. The class
syntax and design are based mostly on Smalltalk, one of the first object-oriented
programming l
i languages.

If you have programmed with object-oriented languages before, the following
information should help you learn the basic syntax of Objective-C. Many of the
traditional object-oriented concepts, such as encapsulation, inheritance, and
object oriented
polymorphism, are all present in Objective-C. There are a few important differences,
but those differences are called out in this article and more detailed information is
available if you need it.

If you have never programmed using an object oriented language before you need
object-oriented before,
to have at least a basic understanding of the associated concepts before
proceeding. The use of objects and object-oriented constructs is fundamental to the
design of iPhone applications, and understanding how they interact is critical to
creating your applications.

36

Files

Extension Source Type
.h Header files. Header files contain class, type, function, and
constant declarations.

.m Source files. This is the typical extension used for source files
and can contain both Objective-C and C code.

.mm Source files. A source file with this extension can contain C++
code in addition to Objective-C and C code.

This t
Thi extension should be used only if you actually refer to C++
i h ld b d l t ll f t C
classes or features from your Objective-C code.

37

#import

When
Wh you want to include header fil i your source code, you can use th
t t i l d h d files in d the
standard #include compiler directive but Objective-C provides a better way.

The #import directive is identical to #include, except that it makes sure that the
same file is never included more than once.

The Objective-C samples and documentation all prefer the use of #import, and
your own code should too.

38

Strings

The NSSt i
Th NSString class provides an object wrapper f strings th t has all of th
l id bj t for t i that h ll f the
advantages you would expect, including built-in memory management for
storing arbitrary-length strings, support for Unicode, printf-style formatting
utilities, and more. Because such strings are used commonly though,
, g y g ,
Objective-C provides a shorthand notation for creating NSString objects from
constant values. To use this shorthand, all you have to do is precede a normal,
double-quoted string with the @ symbol, as shown in the following examples:

NSString* myString = @”Hello Worldn";

NSString* anotherString = [
NSString stringWithFormat:@"%d %s", 1, @"String”
];

39

Note

Cocoa F
C Framework i d i d f
k is derived from th N XTSTEP and OPENSTEP
the NeXTSTEP d
programming environments developed by NeXT in the late 1980s.

Apple acquired NeXT in December 1996, and subsequently went to work on
the Rhapsody operating system that was supposed to be the direct successor
of OPENSTEP.

The OPENSTEP base of libraries and binary support was termed Yellow Box.
Rhapsody evolved into Mac OS X, and the Yellow Box became Cocoa.

As a result, Cocoa classes begin with the acronym "NS" (standing either for the
NeXT-Sun
NeXT Sun creation of OPENSTEP or for the original proprietary term for the
OPENSTEP,
OPENSTEP framework, NeXTSTEP): NSString, NSArray, etc.

40

Class

The specification of a class in Objective C requires two distinct pieces: the
Objective-C
interface and the implementation.

The interface portion contains the class declaration and defines the instance
variables and methods associated with the class
class.

The implementation portion contains the actual code for the methods of the
class.

The class declaration always begins with the @interface compiler directive and
ends with the @end directive. Following the class name (and separated from it
by a colon) is the name of the parent class. The instance (or member) variables
of the class are declared in a code block that is delineated by braces ({ and })
}).
Following the instance variable block is the list of methods declared by the
class. A semicolon character marks the end of each instance variable and
method declaration.

41

Class

@interface MyClass : NSObject

{
int count;
id data;
NSString* name;
}

- (id)initWithString:(NSString *)aName;

+ (MyClass *)createMyClassWithString: (NSString *) aName

@end

42

Class

@implementation MyClass

- (id)initWithString:(NSString *) aName
{
if (self = [super init]) {
count = 0;
data = nil;
name = [aName copy];
return self;
}
}

+ (MyClass *)createMyClassWithString: (NSString *) aName
{
return [[[self alloc] initWithString:aName] autorelease];
}

@end

43

Methods

A class in Objective C can declare two types of methods: instance methods
Objective-C
and class methods.

An instance method is a method whose execution is scoped to a particular
instance of the class In other words before you call an instance method you
class. words, method,
must first create an instance of the class.

Class methods, by comparison, do not require you to create an instance.

The declaration of a method consists of the method type identifier, a return
type, one or more signature keywords, and the parameter type and name
information.

The colon characters declare the presence of a parameter. If a method has no
parameters, you omit the colon after the first (and only) signature keyword. In
this example, the method takes two parameters.

44

Methods

-(void)insertObject:(id)anObject atIndex:(NSUInteger)index
(void)insertObject:(id)anObject

…

[ y
[myArray insertObject:anObj atIndex:0];
y j j ]

Method Type

Return Type

Signature keywords

Parameter Types

Parameter Names

45

Properties

Properties are a convenience notation used to replace accessor method
declarations. Properties do not create new instance variables in your class
declaration.

They are simply a shorthand for defining methods that access existing instance
variables. Classes that expose instance variables can do so using the property
notation instead of using getter and setter syntax. Classes can also use
properties to expose “virtual” instance variables—that is, pieces of data that are
computed dynamically and not actually stored in instance variables.
variables

Practically speaking, properties reduce the amount of redundant code you have
to write. Because most accessor methods are implemented in similar ways,
properties eliminate the need to provide a distinct getter and setter method for
each instance variable exposed in the class. Instead, you specify the behavior
you want using the property declaration and then synthesize actual getter and
setter methods based on that declaration at compile time.

46

Propierties

@property BOOL flag;

@property (copy) NSString* nameObject; //Copy the object during assignment.

@property (
p p y (readonly) UIView* rootView;
y) // Create only a g
y getter method.

…

myObject.flag = YES;

CGRect viewFrame = myObject.rootView.frame;

47

Protocols and Delegates

A protocol declares methods that can be implemented by any class Protocols are not classes
class.
themselves. They simply define an interface that other objects are responsible for
implementing. When you implement the methods of a protocol in one of your classes, your
class is said to conform to that protocol.

In iPhone OS protocols are used frequently to implement delegate objects A delegate object is
OS, objects.
an object that acts on behalf of, or in coordination with, another object.

By example, the UIApplication class implements the required behavior of an application.
Instead of forcing you to subclass UIApplication to receive simple notifications about the current
state of the application, the UIApplication class delivers those notifications by calling specific
methods of its assigned delegate object. An object that implements the methods of the
UIApplicationDelegate protocol can receive those notifications and provide an appropriate
response.

The dec a a o o a p o oco looks s
e declaration of protocol oo s similar to that o a c ass interface, with the e cep o s that
a o a of class e ace, e exceptions a
protocols do not have a parent class and they do not define instance variables.

In the case of many delegate protocols, adopting a protocol is simply a matter of implementing
the methods defined by that protocol. There are some protocols that require you to state
explicitly that y support the p
p y you pp protocol, and p
, protocols can specify both required and optional
p y q p
methods.

48

Time to Work 4
A classical Fraction class

Fraction.h
Fraction h

<Foundation/NSObject.h>
#import <Foundation/NSObject h>

@interface Fraction: NSObject {

int numerator;
int denominator;

}

-(void) print;
-(void) setNumerator: (int) d;
-(void) setDenominator: (int) d;
-(int) numerator;
-(int) denominator;

@end

50

Fraction.m
Fraction m

"Fraction.h"
#import "Fraction h"
#import <stdio.h>

@implementation Fraction

-(void) print { printf( "%i/%i", numerator, denominator ); }

-(void) setNumerator: (int) n { numerator = n; }

-(void) setDenominator: (int) d { denominator = d; }

-(int) denominator { return denominator; }

-(int) numerator { return numerator; }

@end

51

main.m
main m

p
#import <stdio.h>
#import "Fraction.h"

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

Fraction *frac = [[Fraction alloc] init];
[[ ] ]
[frac setNumerator: 1];

[frac setDenominator: 3];

printf( "The fraction is: " );

[frac print];

printf( "n" );

[f l ]
[frac release];

return 0;
}

52

Creating
C ti an A li ti
Application
3.1

Introduction

At a high l
hi h level, th process f creating an iPh
l the for ti iPhone application i similar t th t
li ti is i il to that
for creating a Mac OS X application.

Both use the same tools and many of the same basic libraries. Despite the
similarities, there are also significant differences.

An iPhone is not a desktop computer; it has a different purpose and requires a
very different design approach. That approach needs to take advantage of the
strengths of iPhone OS and forego features that might be irrelevant or
impractical in a mobile environment.

The smaller size of the iPhone and iPod touch screens also means that your
application's user interface should be well organized and always focused on the
information the user needs most.

54

Steps

1. Main

2. Delegate

3.
3 Views

55

Views

1. Main

2. Delegate

3.
3 Views

56

Steps

Initializing the
I iti li i th application
li ti

Displaying a window

Drawing custom content

Handling touch events

57

Project Window Based
Window-Based

1. Foundation

2. CoreGraphics

3.
3 UIKit

58

main.m
main m

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

NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

int retVal = UIApplicationMain(argc, argv, nil, nil);

[pool release];

return retVal;

}

59

Application Delegate

One f th
O of the most important architectural d t il of your project i d fi i th
ti t t hit t l details f j t is defining the
application delegate object, which is instantiated from a class you provide in
your project.

The application delegate class declares its interface in a *.h file and defines its
implementation in a *.m file.

Delegate is responsible of creating the window and views of the apps: using
interface Builder or programatically.

60


#import <UIKit/UIKit.h>

@class MiVista;

@interface HolaMundoAppDelegate : NSObject <UIApplicationDelegate>
{

UIWindow *window;

MiVista *vista;

}

@property (nonatomic, retain) UIWindow *window;

@property (nonatomic, retain) MiVista *vista;

@end

61


HOLAMUNDOAPPDELEGATE.H
#IMPORT "HOLAMUNDOAPPDELEGATE H”
#IMPORT "MIVISTA.H”

@IMPLEMENTATION HOLAMUNDOAPPDELEGATE

@SYNTHESIZE WINDOW;
@SYNTHESIZE VISTA
VISTA;

- (VOID)APPLICATIONDIDFINISHLAUNCHING :(UIAPPLICATION *)APPLICATION {
SELF.WINDOW =
[[[UIWINDOW ALLOC] INITWITHFRAME:[[UISCREEN MAINSCREEN] BOUNDS]] AUTORELEASE];
SELF.VISTA =
[[[MIVISTA ALLOC] INITWITHFRAME:[[UISCREEN MAINSCREEN] APPLICATIONFRAME]] AUTORELEASE];
[WINDOW ADDSUBVIEW:VISTA];
[WINDOW MAKEKEYANDVISIBLE];

}

- (VOID)DEALLOC {
[VISTA RELEASE];
[WINDOW RELEASE];
[SUPER DEALLOC];
}

@END

62

Create a view (programatically)

import <UIKit/UIKit.h>
i
# i / i h
@interface MiVista : UIView {

UILabel *miTexto;

}

@property (nonatomic, retain) UILabel *miTexto;

@end

63

Create a view (programatically)

MiVista.h
##import "MiVista h”
@implementation MiVista(id)initWithFrame:(CGRect)rectangulo {

-(id)initWithFrame:(CGRect)rectangulo {
[super initWithFrame:rectangulo];

self.backgroundColor =[UIColor whiteColor];
lf b k dC l [UIC l hit C l ]
CGRect contenidoRectangulo = self.frame;
CGFloat margenIzquierdo = 90.0;
CGFloat anchoTextField = contenidoRectangulo.size.width * 0.72;
CGFloat posicionTextField = (contenidoRectangulo.size.width - anchoTextField)/2.0;
CGRect etiqueta =
CGRectMake(posicionTextField,margenIzquierdo,anchoTextField,FONT_SIZE* HEIGHT_MULTIPLIER);
UILabel *miTexto = [[UILabel alloc] initWithFrame:etiqueta];
miTexto.text = @"Hola Mundo"; miTexto.font = [UIFont systemFontOfSize:FONT_SIZE];
miTexto.textColor = [UIColor redColor];
miTexto.textAlignment = UITextAlignmentCenter;
[self addSubview:miTexto];
[miTexto release]; return self;}
}

-(void)dealloc {
[super dealloc];
}
@end

64

Touch E
T h Events
t
3.2

Handling Touch Events

UIView are part of UIR
All UIVi t f UIResponder and can i l
d d implement E
t Event “li t
t “listener”
”

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event;
)touches )event;

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event;

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event;

66

Handling Touch Events

67

Plist file
Pli t fil
3.3

plist file

<?xml version="1.0" encoding="UTF-8"?>
l i "1 0" di " 8"
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
"http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>CFBundleDevelopmentRegion</key>
<string>en</string>
<key>CFBundleDisplayName</key>
<string>${PRODUCT_NAME}</string>
<key>CFBundleExecutable</key>
<string>${EXECUTABLE_NAME}</string>
y y
<key>CFBundleIconFile</key>
<string>Icon.png</string>
<key>CFBundleIdentifier</key>
<string>com.yourcompany.${PRODUCT_NAME:identifier}</string>

69

plist file

<key>CFBundleInfoDictionaryVersion</key>
k dl f i i i /k
<string>6.0</string>
<key>CFBundleName</key>
<string>${PRODUCT_NAME}</string>
<key>CFBundlePackageType</key>
<string>APPL</string>
<key>CFBundleSignature</key>
<string>????</string>
<key>CFBundleVersion</key>
<string>1.0</string>
<key>UIStatusBarHidden</key>
<true/>
<key>NSMainNibFile</key>
<string>MainWindow</string>
</dict>
</plist>

70

Interface Builder

File’s Owner, it i a proxy object. It i a
Fil ’ O is bj t is
placeholder for the object responsible of
manage the content.

The library

73

View-Based
View Based Project

Create
C t a view-based project
i b d j t

ViewController f
C files are created
automatically (h, m y xib)

Open ViewController.xib: add text field, a
label, and a button.

Add a UIImage if you want, to complete the
GUI.

74

Connecting the UI with the code

STEP 1: open ViewController h:
ViewController.h:


@interface IBViewController : UIViewController {

IBOutlet UITextField *txtName;

IBOutlet UILabel *lbHello;

}

@property (nonatomic, retain) IBOutlet UITextField *txtName;

@property (nonatomic, retain) IBOutlet UILabel *lbHello;

- (IBAction) updateText:(id) sender;

@end

75

IBOutlet and IBAction

IBOutlet is a null-defined macro, which the C
preprocessor

An outlet is an instance variable that identifies an
object

IBAction, like IBOutlet, is a null defined macro,
which the C preprocessor removes at compile
time

76


STEP 2: open ViewController.xib:
2 Vi C t ll ib

Click in the view (outside button, label and so) : connections inspector : new
reference outlet : and connect to file’s owner proxy object.

Click in the textfield : connections inspector : new reference outlet : and
connect to file’s owner proxy object.

Click in the label : connections inspector : new reference outlet : and connect
to file’s owner proxy object.

Click in the label : connections inspector : Touch up inside: and connect to
file’s owner proxy object.

77


STEP 3: open ViewController.m:
3 Vi C t ll

#import "IBViewController.h”
@implementation IBViewController@synthesize txtName, lbHello;

-(IBAction) updateText:(id) sender {NSString *text;
if ([txtName.text length] == 0) {
text = @"escibe tu nombre";
} else {
text = [[NSString alloc] initWithFormat:@"Hola %@!", txtName.text];
}
lbHello.text = text;[text release];
}

- (void)dealloc {
[super dealloc];
}

@end

78

Navigation
Na igation Based
4.2

Navigation-Based
Navigation Based Project

Create
C t a navigation-based project
i ti b d j t

ViewController f
C files are created and include
a UITable component automatically (h, m y
xib)

Execute the code

80

Updating UITable data

At RootViewController.m
R tVi C t ll

81

UITable and more views together

One
O more View
Vi

Double click RootViewController.xib to open Interface Builder

Click un File New : and select View
C

Add a Label or TextView to the View

Save it inside the project directory. Close Interface Builder and drag the new
XIB file to Resources Folder.

82


One more ViewController
File : New : and select UIViewController subclass.
You need a new m and h file.
In the h file add a new outlet for the textview:

@interface VistaDosViewController : UIViewController {

IBOutlet UITextView* texto;

}

@property (nonatomic, retain) IBOutlet UITextView *texto;
@ i i i

@end

Open IB, select TextView : conections inspector : new outlet, and link with File’s
owner (and select the corresponding ViewController)

83


One
O more ViewController ( m fil )
Vi C t ll file)

84

Associate view and view controller

Double li k in the file VistaDos.xib
D bl click i th fil Vi t D ib

Click File’s Owner, then click tools -> identity inspector

Select VistaDosViewControler in the dropdown class
S C

Click in any place of the view to select it, next tools – connections inspector,
new reference outlet, and drag to file owner.
g

85

Manipulation
Data Manip lation
4.3

Simple Object

Create
C t a new Fil of NSObj t subclass t
File f NSObject b l type.
@interface Fruta : NSObject {
NSString *nombre;NSString *descripcion;
}
@property(nonatomic, copy) NSString *nombre;
@property(nonatomic, copy) NSString *descripcion;

-(id) initWithNombre:(NSString*)n descripcion:(NSString *) d;
@end

#import "Fruta.h“
@implementation Fruta {
@synthesize nombre, descripcion;
-(id) initWithNombre:(NSString*)n descripcion:
(NSString )d {self nombre
(NSString*)d {self.nombre = n;
self.descripcion = d;
return self;}
@end

If you want to create a method constructor this must return “self”.

87

An Array

Open the Delegate.h Fil
O th D l t h File:

@interface TablaAppDelegate : NSObject <UIApplicationDelegate> {
UIWindow *window;
UINavigationController *navigationController;
NSMutableArray *frutas;
}
@p p y (nonatomic, retain) IBOutlet UIWindow *window;
@property ( , ) ;
@property (nonatomic, retain) IBOutlet UINavigationController *navigationController;
@property (nonatomic, retain) NSMutableArray *frutas;
@end

Create array and add a property

88

An Array

Open the Delegate.m File:
#import "TablaAppDelegate.h“
#import "RootViewController.h“
#import "Fruta.h“

@implementation TablaAppDelegate
@synthesize window;
@ th i i d
@synthesize navigationController;
@synthesize frutas;

-(void)applicationDidFinishLaunching:(UIApplication *)application {
Fruta *manzana = [[Fruta alloc] initWithNombre:@"Manzana" descripcion:@"rojas y verdes son deliciosas!"];
Fruta *naranja = [[Fruta alloc] initWithNombre:@"Naranja" descripcion:@"ideal para jugo! ];
naranja initWithNombre:@ Naranja descripcion:@ ideal jugo!"];
Fruta *melon = [[Fruta alloc] initWithNombre:@"Melon" descripcion:@"una fruta poco recomendable!"];
self.frutas =[[NSMutableArray alloc] initWithObjects:manzana, naranja, melon, nil];
// Configure and show the window
[window addSubview:[navigationController view]];
[window makeKeyAndVisible];
}
-(void)applicationWillTerminate:(UIApplication *)application {
// Save data if appropriate
}
-(void)dealloc {
[navigationController release];
[window release];
[super dealloc];
}
@end

89

Principal ViewControler

Open the RootViewController.m File:

-(NSInteger)tableView:(UITableView *) tableView numberOfRowsInSection:(NSInteger)section {
TablaAppDelegate *appDelegate = (TablaAppDelegate*)[[UIApplication sharedApplication] delegate];
return appDelegate.frutas.count;
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease]; }
TablaAppDelegate *appDelegate = (TablaAppDelegate )[[UIApplication sharedApplication] delegate];
appDelegate (TablaAppDelegate*)[[UIApplication
Fruta *f = (Fruta*) [appDelegate.frutas objectAtIndex:indexPath.row];[cell setText:f.nombre];
// [cell setText:@"Hola Mundo"];// Set up the cell return cell;}

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// Navigation logic -- create and push a new view controllerTablaAppDelegate *appDelegate =
(TablaAppDelegate )[[UIApplication
(TablaAppDelegate*)[[UIApplication sharedApplication] delegate];
Fruta *fruta = (Fruta*) [appDelegate.frutas objectAtIndex:indexPath.row];I
f (self.vistaDosViewController == nil) {
VistaDosViewController *vistaDos = [[VistaDosViewController alloc] initWithNibName:@"VistaDos"
bundle:[NSBundle mainBundle]];
self.vistaDosViewController = vistaDos;[vistaDos release];}
[self.navigationController pushViewController:self vistaDosViewController
[self navigationController pushViewController:self.vistaDosViewController animated:YES];
self.vistaDosViewController.title = [fruta nombre];
[self.vistaDosViewController.texto setText:[fruta descripcion]];
}
90

Working more

SQLite
SQLit

iPphone suport the use of databases SQLite.
f SQ

One interesting work outside of this presentation is to convert this simple
Array based table in a database application.
y pp

92

Using the Accelerometers

Provide input for the system and for your own custom applications

Measures changes in velocity along a single linear axis.

iPhone have three accelerometers in a 3D space, to detect motion in any direction.
p y

By tracking which accelerometers are registering acceleration, and the extent of
that acceleration, you can detect the physical orientation of a device in 3D space.
You can then apply this orientation and its changes as inputs to your application.

The UIViewController class provides the infrastructure needed to rotate your
interface and adjust the position of views automatically in response to orientation
changes.

UIAccelerometer object in UIKit allow you t access to the raw accelerometer d t
UIA l t bj t i ll to t th l t data
directly. This object reports the current accelerometer values. You can also use the
data to detect the device's orientation or to detect other types of instantaneous
motion, such as the user shaking the device back and forth. You can then use this
information as input to a g
p game or other application.
pp

94

Classes,
Classes objects and methods

Every application h
E li ti have an UIA l
UIAcelerometer object.
t bj t

To get an instance of this class, you use sharedAccelerometer method of
UIAccelerometer.

Whit this object you set (updateInterval) the reporting interval (minum 10
miliseg = 100 Hz) and a delegate to receive acceleration events
(UIAccelerometerDelegate).

Use accelerometer:didAccelerate : method to process accelerometer data.
- (void)accelerometer:(UIAccelerometer *) accelerometer
didAccelerate:(UIAcceleration *) acceleration.
didA l t (UIA l ti l ti
UIAccelerationValue object could store the value of an axis.

95


Isolating the Gravity Component From Acceleration Data (detect changes of orientation) using a low-
low
pass filter. accelX, accelY and accelZ are member variables that settle out quickly and respond slowly
to sudden changes in motion.

Isolating Instantaneous Motion From Acceleration Data (movement changes) using a high-pass filt
I l ti I t t M ti F A l ti D t ( t h ) i hi h filter

Current Device Orientation
Use UIDevice l
U UID i class methods: th d
beginGeneratingDeviceOrientationNotifications
current orientation is stored at orientation properties
UIDeviceOrientationChangeNotification posted whenever orientations change
UIDeviceOrientation constants (landscape or portrait, face up or down)
portrait

Disabling orientation notifications
Use the endGeneratingDeviceOrientationNotifications

96

Getting the User's Current Location
User s

go.
Devices that run iPhone OS are meant for users on the go

Therefore the software you write for these devices should also take this fact into account. And
because the Internet and web make it possible to do business anywhere, being able to tailor
information for the user's current location can make for a compelling user experience.

The Core Location framework monitors signals coming from cell phone towers and Wi-Fi
hotspots and uses them to triangulate the user's current position.

You can use this framework to grab an initial location fix only or you can be notified whenever
only,
the user's location changes. With this information, you can filter the information your application
provides or use it in other ways.

Retrive Current Location. Create an instance of CLLocationManager class.

To begin receiving notifications, assign a delegate and call the startUpdatingLocation method.

When new location information is available the manager notifies the delegate.

98

Playing Audio and Video

iPhone OS supports audio features in your application through the Core Audio and
OpenAL frameworks, and provides video playback support using the Media Player
framework.

Core Audio provides an advanced interface for playing, recording, and manipulating
sound and f parsing streamed audio. Y can use i to play b k simple sound
d d for i d di You it l back i l d
effects or multichannel audio, mix sounds and position them in an audio field, and
even trigger the vibrate feature of an iPhone. If you are a game developer and
already have code that takes advantage of OpenAL, you can use your code in
iPhone OS to position and play back audio in your games.

The Media Player framework is what you use to play back full-screen video files.
This framework supports the playback of many standard movie file formats and
gives you control over the playback environment, including whether to display user
controls and how to configure the aspect ratio of video content
content.

Game developers might use this framework to play cut scenes or other prerendered
content, while media-based applications can also use this framework to play back
movie files.

99

Exercises and
References
6

iPhone Dev Center

http://developer.apple.com/iphone

101

200810 - iPhone Tutorial

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