Objective-C Primer. iphone Programmer s Association. Lorenzo Swank September 10, 2008

Transcription

1 Objective-C Primer iphone Programmer s Association Lorenzo Swank September 10, 2008

2 Disclaimer Content was blatantly and unapologetically stolen from the WWDC 2007 Fundamentals of Cocoa session, as well as from CocoaDevCentral.com. This content, the ipa modifications to it, and my sarcastic comments are not endorsed or approved by the original content authors. All material is used for academic purposes and is, therefore, probably fair use. Thank you.

3 Overview What is Cocoa Touch? Objective-C Overview

4 Resources Apple Developer Connection Resource Library

5 What is Cocoa Touch? Object-oriented APIs Frameworks Foundation UIKit Others

6 Foundation Core framework for non-ui functionality - Root class

7 Foundation Core framework for non-ui functionality - Root class NSObject

8 Foundation Core framework for non-ui functionality - Root class - Operating system facilities and interaction NSFileManager, NSBundle, NSPort, NSStream, NSTask, NSHost, NSRunLoop, NSDate

9 Foundation Core framework for non-ui functionality - Root class - Operating system facilities and interaction - Internationalization NSString, NSCharacterSet, NSNumberFormatter, NSDateFormatter, NSLocale

10 Foundation Core framework for non-ui functionality - Root class - Operating system facilities and interaction - Internationalization - Collections NSArray, NSMutableArray, NSDictionary, NSSet, Property Lists

11 Foundation Core framework for non-ui functionality - Root class - Operating system facilities and interaction - Internationalization - Collections - Scripting NSAppleScript, NSScriptCommand

12 Foundation Core framework for non-ui functionality - Root class - Operating system facilities and interaction - Internationalization - Collections - Scripting - XML processing, Web access NSXMLParser, NSXMLDocument, NSXMLNode, NSURL, NSUrlRequest, NSUrlResponse

13 Foundation Core framework for non-ui functionality - Root class - Operating system facilities and interaction - Internationalization - Collections - Scripting - XML processing, Web access - Lots of other stuff

14 UIKit Core framework for UI functionality - Top Level Interfaces UIApplication, UIScreen

15 UIKit Core framework for UI functionality - Top Level Interfaces - Drawing UIWindow, UIView, UIColor, UIFont, UIImage, UIImageView

16 UIKit Core framework for UI functionality - Top Level Interfaces - Drawing - Event Handling UIEvent, UIAcceleration, UIAccelerometer, UITouch

17 UIKit Core framework for UI functionality - Top Level Interfaces - Drawing - Event Handling - Standard Controls UIControl, UIButton UILabel, UISegmentedControl, UIActivityIndicatorView, UIDatePicker

18 UIKit Core framework for UI functionality - Top Level Interfaces - Drawing - Event Handling - Standard Controls - Standard Views UIScrollView, UIWebView, UITableView

19 UIKit Core framework for UI functionality - Top Level Interfaces - Drawing - Event Handling - Standard Controls - Standard Views - Standard View Controllers UIViewController, UINavigationController, UITabBarController, UITableViewController, UIImagePickerController

20 Interface Builder

21 UICatalog

22 What is Objective-C? Small superset of C - ANSI C - Some additional syntax - A few additional types Dynamic object runtime Single inheritance

23 Objective-C Defining a Method -(void)setwidth:(int)width height:(int)height { _width = width; _height = height; } Sending a message (Calling a method) [contentview setwidth:100 height:100]; [[viewarrays objectatindex:n] setwidth:100

24 Objective-C C Style: Method Names CreateAlertView(0.0f, 0.0f, 200.0f, 150.0f, warnstring, TRUE); Objective-C Style [[AlertView alloc] initwithoriginx: 0.0f originy: 0.0f width: 200.0f height: 150.0f text: warningstring, fadeoutwhenfinished: TRUE];

25 Objective-C Referring to a Method SEL myselector Referring to an object Widget* currwidget; id currwidget; Referring to self [self setwidth:150 height:150];

26 Objective-C String literals NSString* stringname This is a little text ;

27 Memory Management Cocoa Touch objects are reference counted

28 Memory Management Cocoa Touch objects are reference counted A freshly created object has a reference count of one Widget* mywidget = [[Widget alloc] init]; Widget* yourwidget = [mywidget copy];

29 Memory Management Cocoa Touch objects are reference counted A freshly created object has a reference count of one Widget* mywidget = [[Widget alloc] init]; Widget* yourwidget = [mywidget copy]; retain increments the reference count

30 Memory Management Cocoa Touch objects are reference counted A freshly created object has a reference count of one Widget* mywidget = [[Widget alloc] init]; Widget* yourwidget = [mywidget copy]; retain increments the reference count release decrements the reference count

31 Memory Management Cocoa Touch objects are reference counted A freshly created object has a reference count of one Widget* mywidget = [[Widget alloc] init]; Widget* yourwidget = [mywidget copy]; retain increments the reference count release decrements the reference count An instance of the object is deallocated when its reference count reaches 0 - Object is sent dealloc

32 Memory Management Cocoa Touch objects are reference counted A freshly created object has a reference count of one Widget* mywidget = [[Widget alloc] init]; Widget* yourwidget = [mywidget copy]; retain increments the reference count release decrements the reference count An instance of the object is deallocated when its reference count reaches 0 - Object is sent dealloc autorelease decrements a reference count later

33

34 Memory Management

35 Memory Management

36 Reference Counting alloc [NSObjectInstance alloc] +1 copy [NSObjectInstance copy] +1 retain [NSObjectInstance retain] +1 release [NSObjectInstance release] -1 autorelease [NSObjectInstance autorelease] -1*

37 Object Ownership If you create it, you own it. alloc/init, copy If you were handed an object you re going to need, retain it. When you pass an object to someone else don t retain it for them.

38 Important Concerns What happens if you release an object before you are done with it?... if an object is deallocated before you are done with it?... if you explicitly call dealloc?... if you don t retain an object that you need?

39 Summary Cocoa Touch Frameworks Foundation UIKit Objective-C Syntax Memory Management

40 End

41 ipa Areas of Research Call for Volunteers iphone Hardware Interfacing with other devices UIKit Making it do things that are not allowed