iPhone Tech Talk
5.13.2009

Outline

Outline
• Overview of Objective C

Outline
• Overview of Objective C
• Interface Builder and XCode

Outline
• Overview of Objective C
• Interface Builder and XCode
• iPhone App Store

History

History
• Started in 1980, layered on C language

History
• Started in 1980, layered on C language
• NeXT Licensed 1988

History
• Started in 1980, layered on C language
• NeXT Licensed 1988
• Added to Free Software Foundation GNU
in 1992

History
• Started in 1980, layered on C language
• NeXT Licensed 1988
• Added to Free Software Foundation GNU
in 1992
• Apple acquired NeXT in 1996

Language &
Development
• Needs header files (*.h) and implementation files (*.m)
• Can mix C and Objective C
• Cocoa enforces MVC framework
• Can also write OpenGL applications

Syntax
UIView *view = [[UIView alloc] init];
[view setBackgroundColor:[UIColor whiteColor]];

Syntax
UIView *view = [[UIView alloc] init];
[view setBackgroundColor:[UIColor whiteColor]];
PHP
$view = new UIView();
$view->backgroundColor(UIColor::whiteColor);

Syntax
UIView *view = [[UIView alloc] init];
[view setBackgroundColor:[UIColor whiteColor]];
PHP
$view = new UIView();
$view->backgroundColor(UIColor::whiteColor);
Actionscript
var view:UIView = new UIView();
view.backgroundColor(UIColor.whiteColor);

Example
1 #import <UIKit/UIKit.h>
2
3 @interface Foo : NSObject {
4 NSString *myString;
5 }
6 @property NSString *myString;
7 - (NSNumber *) getANSNumber;
8 + (void) callStaticMethod;
9 @end
10
11 @implementation Foo
12 @synthesize myString;
13 - (id)init {
14 self = [super init];
15 [self setMyString: @”ASDF”];
16 return self;
17 }
18 @end

Tools

Tools
XCode

Tools
XCode Interface Builder

Tools
XCode Interface Builder
Tools to develop iPhone/Mac applications is
free to anyone who runs a machine with OS X

UINavigation Elements

Demo

Interface Builder
Mode Attribute
• Define how the object will be aligned inside the view.
Tag
• Language-independent way of identifying objects on your interface.
• Multiple button using same method can be identified via tag
Opaque
• Tells iPhone OS that nothing below your view should be drawn and allows
iPhones’s drawing method to do some optimizations that speed up drawing
Clip Subviews
•If your view has subviews and this option is checked. Then only the portion of
your subview that is within the bound of your view is drawn.
•This option is turned off by default for performance reason.
Clear Context before Drawing
•iPhone will draw the entire area covered by the control in transparent black
before it actually draws the control.

Demo

Memory Management
iPhone version of Objective-C uses Retain/Release count
method to manage memory.
Retain count is affected by:
• alloc – NSString *label = [[NSString alloc] initWithString:@\"Label\"];
• copy – NSString *label2 = [label copy];
• new - Point *point = [Point new];
• retain – [label2 retain];
Balance retain count with release
• release – [label2 release];
Autorelease Object
•returned from factory method
•NSString *label = [NSString stringWithFormat:@\"label %d\", 2];
• get added to autorelease pool that is released at the end of the run
loop

Memory Usage
iPhone app has access to limited memory
• Memory warning via didReceiveMemoryWarning method
• Use Instruments to find leaks or performance enhancement.
• Use lazy loading
• Watch autorelease footprint
• If needed create autorelease pool
• Watch custom setter method
• Reuse memory
• Update existing object rather then creating new ones
• UITableView uses dequeueReusableCellWithIdentifier:
method
•Returns a reusable table-view cell object located by its
identifier

Demo

Developer Program

Developer Program
• $99 for individual

Developer Program
• $99 for individual
• $99 for company

Developer Program
• $99 for individual
• $99 for company
• $299 for enterprise

Developer Program
• $99 for individual
• $99 for company
• $299 for enterprise
• Meant for developers!

Beta Testing &
Distribution

Beta Testing &
Distribution
• Provisioning profiles

Beta Testing &
Distribution
• Provisioning profiles
• Can install development builds through XCode

Beta Testing &
Distribution
• Provisioning profiles
• Can install development builds through XCode
• Ad Hoc distribution for external beta testing

Beta Testing &
Distribution
• Provisioning profiles
• Can install development builds through XCode
• Ad Hoc distribution for external beta testing
• App Store - get in EARLY!

Approval Process
• Don’t add obscenities, pornography, etc
• Follow Apple Human Interface Guidelines
• Don’t collect data without user’s consent
• Don’t write malicious software
• Don’t write an app that Apple is already writing

Approval Process

iPhone 3.0

iPhone 3.0
• All Apps being reviewed in iPhone 3.0

iPhone 3.0
• All Apps being reviewed in iPhone 3.0
• Push Notifications

iPhone 3.0
• All Apps being reviewed in iPhone 3.0
• Push Notifications
• Internal Maps

iPhone 3.0
• All Apps being reviewed in iPhone 3.0
• Push Notifications
• Internal Maps
• Internal Mail

iPhone 3.0
• All Apps being reviewed in iPhone 3.0
• Push Notifications
• Internal Maps
• Internal Mail
• Streaming Video

Resources
• Stanford iPhone Development Class (iTunes)
• Programming in Objective-C 2.0
• Beginning iPhone Development
• The iPhone Developer’s Cookbook
• http://www.docstoc.com/docs/3731208/11-Performance

Questions?