This document provides an agenda for a presentation on programming in Objective-C. It introduces Xcode and common frameworks like UIKit. It discusses Objective-C concepts like message passing and memory management. It also covers design patterns frequently used in iOS like delegation, notifications, and singleton. Common UIKit classes like view controllers and views are demonstrated.

1. 新⽵竹碼農
Programming In
Objective-C
by J.P. Sun

2. Agenda
❖ Xcode introduction
❖ Objective-C overview
❖ Design patterns
❖ CocoaTouch Frameworks

3. Xcode : First Project
❖ Generate From a Template : CocoaTouch/SingleView
❖ Navigator
❖ Project settings
❖ Xcode 101 : Show Toolbar

4. Start Developing iOS Apps Today
https://developer.apple.com/library/ios/referencelibrary/GettingStarted/
RoadMapiOS/FirstTutorial.html#//apple_ref/doc/uid/TP40011343-CH3-
SW1

5. UIApplicationMain
❖ UIApplicationMain:
❖ This function is called in the main
entry point to create the
application object and the
application delegate and set up
the event loop. #Apple doc
UIApplication
AppDelegate
UIApplicationMain create
Xcode create

6. Breakpoint tip
Break on Throw && neglect C++ Throw

7. Agenda
❖ Xcode introduction
❖ Objective-C overview
❖ Design patterns
❖ CocoaTouch Frameworks

8. Message passing
[instance method];
寫 iOS 最先看習慣的就是中括號

9. Compiler added
Garbage collection

10. @autoreleasepool
int main(int argc, char * argv[]) {
@autoreleasepool {
return UIApplicationMain(argc, argv,
nil, NSStringFromClass([AppDelegate class]));
}
}
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSLog(@"Programming is fun!");
[pool drain];
return 0;
ARC / LLVM-3
Before ARC
Where [object autorelease] goes, and release on [pool drain]

11. Dynamism
objective-C runtime library
https://github.com/tomjpsun/PIOC

12. .h
#import <Foundation/Foundation.h>
@interface Fraction: NSObject
{
int numerator;
int denominator;
}
-(void) print;
-(void) setNumerator: (int) n;
-(void) setDenominator: (int) d;
@end

13. .m
#import "Fraction.h"
@implementation Fraction
-(void) print
{
NSLog(@"%i/%i", numerator, denominator);
}
-(void) setNumerator: (int) n
{
numerator = n;
}
-(void) setDenominator: (int) d
{
denominator = d;
}
@end

14. Multiple arguments
-(void) setTo: (int) n over: (int) d
{
numerator = n;
denominator = d;
}
int main (int argc, char *argv[])
{
Fraction *aFraction = [[Fraction alloc] init];
[aFraction setTo: 1 over: 3];
[aFraction print]; // -> 1/3
return 0;
}

15. Class method
@interface Fraction: NSObject
{
int numerator;
int denominator;
}
@interface FractionFactory: NSObject
+(Fraction*) newFractionWithNumerator: (int)numerator
andDenominator: (int)denominator;
int main (int argc, char *argv[])
{
Fraction* f = [FractionFactory
newFractionWithNumerator: 1
andDenominator: 2];
}

16. Synthesized accessor
#import <Foundation/Foundation.h>
• @interface Fraction: NSObject
• {
• int numerator;
• }
• -(void) setNumerator: (int) n; // setter
• -(int) numerator; // getter
• @end
@interface Fraction: NSObject
@property numerator;
@end
@implementation Fraction
@synthesis numerator;
@end
compiler generates getter/setter

17. Dot accessing property
[ instance setPoperty: 2];
is equal to
instance.property = 2;

18. self
• self like this in C++
- (id)init
{
self = [super init];
if (self) {
// Custom initialization
}
return self;
}

19. id
• something like void*
• useful at runtime

20. selector
• name of method , function literal
• compile time
SEL aSelector = @selector(methodName);
• run time
SEL aSelector = NSSelectorFromString(@"print");
NSString* selectorStr =
NSStringFromSelector(aSelector);
NSLog(@"%@", selectorStr);

21. selector
[friend performSelector:@selector(gossipAbout:)
withObject:aNeighbor];
is equal to
[friend gossipAbout:aNeighbor];

22. Agenda
❖ Xcode introduction
❖ Objective-C overview
❖ Design patterns
❖ CocoaTouch Frameworks

23. delegate
iOS
UIApplication
object
MyApp
App 可以開始嗎？
可以
delegate
implemented via @protocol

24. delegate
iOS
UIApplication
object
MyApp
App 將要結束！
delegate
implemented via @protocol
不⽤用回答，因為只
是知會你的 App

25. delegate
iOS
UIApplication
object
MyApp
delegate
implemented via @protocol
some delegates
are optional
@protocol

26. delegate
• no need to subclassing everywhere.
• de-coupling decision, cleaner design.

27. delegate demo
https://github.com/tomjpsun/TestObjc.git

28. Data-Source
• nearly the same as delegate, 但是提供 data
⽽而⾮非 UI 決策.
TableView
Controller
有幾個 sections ?
4
sec 1 cell 1
“Clear History”
Data Source

29. Target-Action
- (void)viewDidLoad
{
[super viewDidLoad];
[self.myButton addTarget:self
action:@selector(myButtonPressed:)
forControlEvents:UIControlEventTouchUpInside];
}
- (void)myButtonPressed:(UIButton*)button
{
...
}
ViewController
-(void)myButtonPressed:
Button
send message when the
event occurs

30. Notification
Notification
Center
anObject
observer 1
observer 2
observer 3
post
notification
broadcast
notification
reduce the code coupling

31. Notification register/
unregister
- (void)dealloc
{
[[NSNotificationCenter defaultCenter]
removeObserver: self];
}
- (void)viewDidLoad
{
[ [NSNotificationCenter defaultCenter]
addObserver:self
selector:@selector(playerItemDidReachEnd:)
name:AVPlayerItemDidPlayToEndTimeNotification
object:[RODModel shareInstance].player.playerItem ];
. . .
AVPlayer will send out this predefined Notification

32. Singleton
• 系統內，只能有⼀一份 instance，以某種標
準的 shared ⽅方式共⽤用之.
Typical class
request 1
response 1
A
request 2
response 2
B
Singleton
request 1
response 1
A
request 2
response 2

33. Singleton
• 是好的 design pattern ? 正反⾯面討論很多
• CocoaTouch 常⽤用 singleton pattern 表⽰示
某特殊物件
NSFileManager
Notification
Center
UIApplication

34. Agenda
❖ Xcode introduction
❖ Objective-C overview
❖ Design patterns
❖ CocoaTouch Frameworks

35. UIKit Philosophy
• MVC

36. View Controllers

37. Anatomy

38. View Controllers
ManageViews

39. View Controllers
ManageViews

40. View Controllers
ManageViews

41. View

42. Important Documents
View Controller Programming Guide for iOS
View Programming Guide