Beginning to iPhone development

iPhone
Objective-C, UIKit

bofeng@corp.netease.com
@vonbo

Agenda

• overview
• objective-c
• iPhone UIKit

First iPhone App

• Hello world!

Things we have

• Hello world!

• xcode SDK
• & test with Simulator

• test with iPhone/iPod touch ($99)
• appstore

•

Objective C
•
•
• runtime
• foudation framework: values and collection classes
•
• category
• protocol

Beginning to iPhone development

objective c
• @

• @interface, @implementation, @class

• @property, @synthesize

• @protocol

• NSString* str = @”hello world”

• [receiver message]

• C C++

Sample Code
class and message

runtime
• id
• class & className
• respondsToSelector
• performSelector
• isKindOfClass (super class included)
• isMemberOfClass
• @selector

@selector

• SEL
• C++

action
CGRect rect = CGRectMake(20, 20, 100, 30);
UIButton* myButton = [UIButton
buttonWithType:UIButtonTypeRoundedRect];
myButton.frame = rect;
[myButton setTitle:@"my button"
forState:UIControlStateNormal];
[myButton addTarget:self action:@selector(btnClick:)
forControlEvents : UIControlEventTouchUpInside];
[self.view addSubview:myButton];

Foundation Framework
• Value and Collection Classes
• User defaults
• Archiving
• Task, timers, thread
• File system, I/0
• etc ...

Value and Collection
Classes
• NSString & NSMutableString
• NSArray & NSMutableArray
• NSDictionary & NSMutableDictionary
• NSSet & NSMutableSet
• NSNumber [a obj-c object wrapper for basic C
type]
• (NSNumber* num = [NSNumber
numberWithInt:3])

Sample Code
collection classes

• alloc new

• alloc&dealloc C++ new&delete

• but with ...

• alloc new copy
1.
retain

release
• 0
Obj-C dealloc
dealloc
dealloc

Sample Code
“ ” ...
memory management

Getter & Setter
@property & @synthesize

• new alloc copy
1.

release

•
retain release

but how to solve this ?
- (Person*) getChild {
Person* child = [[Person alloc] init];
[child setName:@”xxxx”];
....
// will return ... [child release] or not ?
return child;
}

Autorelease
• NSAutoreleasePool* pool ...
• [object autorelease]
• autorelease

NSAutoreleasePool

release

That’s why create pool
ﬁrst ...
int main(int argc, char* argv[]) {
NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
// put your own code here ...
[pool release];
}

how to solve this ?
- (Person*) getChild {
Person* child = [[Person alloc] init];
[child setName:@”xxxx”];
....
// will return ... [child release] or not ?
return [child autorelease];
}

Autorelease Pool
•
• NSMutableArray pool
• autorelease Array
• pool Array
release

• autorelease pool
autorelease
pool pool

Autorelease Pool Stack
NSAutoreleasePool* poolFirst ..
for (int i=0; i < 10000; i++) {
NSAutoreleasePool* poolSecond ...
// have some autorelease object
// [object autorelease]
[poolSecond release];
}
// other code
[poolFirst release];

Autorelease Pool
•
• NSAutoreleasePool

• alloc release
• Autorelease pool retain
autorelease [pool retain] or [pool autorelease]
• AutoreleasePool “
”
• pool pool
iphone
release autorelease

• new alloc copy
1.
release autorelease
•
1

[NSString stringWithString:@”objc”]
•
retain release

Sample Code
something about class cluster ...

Protocol
• familiar with C++ virtual class
• familiar with Java’s interface
•

• @optional
@required
warning required

protocol

@protocol TwoMethod
- (void) oneMethod;
- (void) anotherMethod;
@end

Class & Protocol
@interface MyClass : NSObject <TwoMethod> {
}
@end

@implementation MyClass
-(void) oneMethod {
// oneMethod’s implementation
}
- (void) anotherMethod {
// anotherMethod’s implementation
}
@end

Objective C
•
•
• runtime id, @selector, respondsToSelector ...
• foudation framework: values and collection classes
•
• category class cluster “ ”
• protocol

Using Objective-C Now !

• without mac
• ubuntu:
• sudo apt-get install gnustep gnustep-devel
• bash /usr/share/GNUstep/Makeﬁles/
GNUstep.sh
• GNUmakeﬁle
• http://forum.ubuntu.org.cn/viewtopic.php?
t=190168

iPhone Application
• &
• MVC
• Views (design & life cycle)
• Navigation based & Tab Bar based application
• very important TableView
•
• Web service

UIApplication
• Every application must have exactly one instance of
UIApplication (or a subclass of UIApplication). When
an application is launched, the UIApplicationMain
function is called; among its other tasks, this
function create a singleton UIApplication object.

• The application object is typically assigned a
delegate, an object that the application informs of
signiﬁcant runtime events—for example, application
launch, low-memory warnings, and application
termination—giving it an opportunity to respond
appropriately.

UIApplicationMain

• delegateClassName
• Specify nil if you load the delegate object
from your application’s main nib file.
• from Info.plist get main nib file
• from main nib file get the application’s
delegate

UIControl

• UILabel
• UIButton
• UITableView
• UINavigatorBar
• ...

Without IB ?
create a button and bind event by code

Views
• View view
superview subviews
• iphone app window Views
window window view (top level)

• view
• - (void)addSubview:(UIView *)view;
• - (void)removeFromSuperview;
• Superviews retain their subviews
• UIView CGRect CGPoint
CGSize

View’s life cycle & hook
function
• initWithNibName:bundle
• viewDidLoad
• viewWillAppear
• viewWillDisappear
• ...maybe viewDidUnload
• hook function
• shouldAutorotateToInterfaceOrientation
• didReceiveMemoryWarning

UINavigationController

• manages the currently displayed screens using the
navigation stack
• at the bottom of this stack is the root view controller
• at the top of the stack is the view controller currently
being displayed
• method:
• pushViewController:animated:
• popViewControllerAnimated:

UITabBarController
• implements a specialized view controller that
manages a radio-style selection interface
• When the user selects a speciﬁc tab, the tab
bar controller displays the root view of the
corresponding view controller, replacing any
previous views
• init with an array (has many view controllers)

Combine

• UI

• TabBarController Based +
NavigationController

Demo
Combine UITabBarController &
UINavigationController

TableView

• display a list of data
• Single column, multiple rows
• Vertical scrolling
• Powerful and ubiquitous in iPhone
applications

Display data in Table View
•
• Table views display a list of data, so use an array
• [myTableView setList:myListOfStuff];
•
• All data is loaded upfront
• All data stays in memory
•
• Another object provides data to the table view
• Not all at once
• Just as it’s needed for display
• Like a delegate, but purely data-oriented

Demo
UITableView <UITableViewDataSource>

Demo
UITableView <UITableViewDelegate>

UITabBar + UINavigation + UITableView !

NavigationController

TableViewController

TabBarController

Demo
UITabBar + UINavigation + UITableView

• Propery Lists, NSUserDefaults
• SQLite
• Core Data

SandBox

• Why keep applications separate?
• Security
• Privacy
• Cleanup after deleting an app

Sample: /Users/xxx/library/Application Support/iPhone Simulator/4.0/Applications

Property Lists
• Convenient way to store a small amount of data
• Arrays, dictionaries, strings, numbers, dates, raw data
• Human-readable XML or binary format
• NSUserDefaults class uses property lists under the hood
• When Not to Use Property Lists

• More than a few hundred KB of data

• Custom object types

• Multiple writers (e.g. not ACID)

Demo
Save data with NSUserDefaults

SQLite
• Complete SQL database in an ordinary ﬁle
• Simple, compact, fast, reliable
• No server
• Great for embedded devices
• Included on the iPhone platform
• When Not to Use SQLite
• Multi-gigabyte databases
• High concurrency (multiple writers)
• Client-server applications

SQLite Obj-C Wrapper

• http://code.google.com/p/ﬂycode/source/browse/
trunk/fmdb

• A query maybe like this:

• [dbconn executeQuery:@"select * from call"]

Using Web Service
• Two Common ways:
• XML
• libxml2
• Tree-based: easy to parse, entire tree in memory
• Event-driven: less memory, more complex to manage state
• NSXMLParser
• Event-driven API: simpler but less powerful than libxml2
• JSON
• Open source json-framework wrapper for Objective-C
• http://code.google.com/p/json-framework/

NSURLConnection
• NSMutableURLRequest
• - connectionWithRequest: delegate
• delegate method:
• – connection:didReceiveResponse:
• – connection:didReceiveData:
• – connection:didFailWithError:
• – connectionDidFinishLoading:

Demo
use json-framework and NSURLConnection with hi-api

iPhone Application

• &
• MVC
• Views (design & life cycle)
• Navigation based & Tab Bar based application
& TableView
• (sandbox, property list,
sqlite)
• Web service

• Objective-C
• The iPhone Developer’s Cookbook
• Programming in Objective-C 2.0
•
• Stanford iPhone dev course
• iTunes iTune Store cs193p
mac windows

Beginning to iPhone development

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