Transcript OS X Development

OS X Development
Tom Schroeder
Table of Contents
Who cares?
History
Objective-C
Cocoa
Environment
Design
Who cares?
Objective-C
TIOBE: Language of the Year - 2011
Currently ranked #3
Mac and OS X market share continues to rise
Flourishing App Store
OS X and iOS apps numerous
History
1985: Steve Jobs leaves Apple
Jobs founds NeXT
Mission: Create powerful computers for universities
NeXTSTEP
Object-Oriented, Multitasking Operating System
Interesting Note
Tim Berners-Lee designed and built first web browser on NeXTSTEP
1996: NeXT purchased by Apple
NeXTSTEP becomes Mac OS X
2001: Cheetah (10.0)
2012: Mountain Lion (10.8)
Objective-C
Object-oriented language
ANSI C language (strict
superset)
Smalltalk-inspired
extension
Developed in early 80s
Stepstone (Brad Cox and
Tom Love)
Goal: facilitate reusability
and backwards compatible
to C
Features & Constructs
Messages
Interfaces and
Implementation
Properties
Object Life Cycle
ARC
Protocols
Categories
Dynamic Typing
Messages
Message is sent
Target and interpretation of message calculated
runtime
Inspired by Smalltalk
Bracket Syntax
Interface and Implementation
Declaration and Definition
Interface - @interface
Instance variables
Properties
Method declarations
Inheritance
Protocol adoption
Implementation - @implementation
Definition of methods, properties, protocol
conformity
Properties
Simple way to declare accessor methods
Encapsulation
Methods are generated by compiler - @synthesize
Allow use of “dot syntax”
Declaration contains attributes
Writability (readonly, readwrite)
Setter semantics (strong, weak, copy, assign, retain)
Atomicity
Object Life Cycle
1
2
1
0
alloc
retain
release
release
Retain-Release Process
Object Life Cycle - ARC
ARC: Automatic Reference Counting
Automatic memory management
Compiler inserts retains and releases
Restrictive but effective
Bridge casting
C-style cast
void *
Protocols
Declare methods to be implemented by a class
Adoption and Conformity
Similar to “interface” in Java
Objects can be referred to by the adopted protocol
id <NSTabViewDelegate> delegate;
Categories
Open classes
Add methods to existing classes (even those in an
imported framework)
Extensions
Anonymous categories
Commonly used to redeclare readonly property as
readwrite
Dynamic Typing
id type
Pointer to Objective-C object
Message Forwarding
Handle message
Drop message
Pass it on
Blocks
Anonymous Functions
Similar to standard C
functions
Usage
Encapsulate code groups
to execute concurrently
Dispatch
Execute on items in a
collection
Fast enumeration
Easily parameterized
Comparison to C++
Objective-C is true superset of C (simple - small addition)
C++ is complex - adds features such as templates, operator
overloading, etc.
C++ is generally faster
Objective-C’s runtime is more complex (dynamic typing &
message passing)
Objective-C is dynamically typed
Objective-C has built-in synchronization
@synchronize
Cocoa
Framework that provides applications the distinctive
look and feel often associated with OS X
Underlying Frameworks
Foundation Kit
Application Kit
Core Data
Other frameworks
Foundation
Collection of base layer classes
Applications can be created solely with Foundation
Command line tools
Functionalities
General object behavior and life cycle
NSObject – base class
Localization
Portability
Wrappers
Primitives
Operating system level functionality
Ports
File I/O
Threads
Foundation Classes
Contains over 100 different classes
NSObject - base class
alloc, init, class
conformsToProtocol:
performSelector:onThread:withObject:waitUntilDone:
NSString
NSMutableString
NSArray
NSMutableArray
NSThread
NSDate
NSURL
AppKit
Contains objects required in creating a graphical
application
Windows
Buttons
Scroll Boxes
Text Fields
Views
NSView, NSTextView
Controllers
NSViewController, NSWindowController
Core Data
Provides means to manage the data of an application
Data model
Serialization
XML
Binary
SQLite
Persistence
Managed Objects
Command Pattern
Undo/Redo
Other Frameworks
Audio & Video
Core Audio
Core Video
Core MIDI
Graphics/Animation
Core Animation
Core Image
OpenGL
Quartz
Bridges
Ruby
Python
Networking
Bonjour
Kerberos
Environment
Great environment  Excellent development experience
Tools
Xcode
General IDE
Utilities
Apple LLVM Engine
Backend
Interface Builder
Graphical Interface Designer
Xcode
General IDE
Code Editor
LLVM Engine Integration
Interface Builder Integration
Project Navigation
Utilities
Version Editor
Instruments
Xcode
LLVM Engine
Compiler - Clang
C/Objective-C/C++
Syntax Highlighting
Code Completion
Live Issues
Fix-it
Static Analysis
Improper memory allocation
Unreachable code
Improper loops
llvm.org
Interface Builder
Integrated into Xcode
Design graphical interfaces for
application
Drag and Drop
WYSIWYG
IBActions & IBOutlets
Connect visual design to code
Interface Builder
Design
Objective-C and Cocoa utilize many design patterns
and constructs
Provides stability and familiarity
Design Patterns
Model-View-Controller
Delegation
Others…
Model-View-Controller
Divides system into three components
Model
Domain-specific data and operations
Platform-independent
View
Responsible for graphically displaying the model
Controller
Mediator for the model and view
Handles interactions with the system
Model-View-Controller
ParcPlace Systems, Inc.
Smalltalk-80 MVC Paradigm
Model-View-Controller
Mediator
Controller
Model
View
Observer
Command
Delegation
One class delegates action to another (helper object)
Inversion of control
Delegate & Delegator
Pass notifications
No polling
Utilizes protocols
Delegate conforms to methods for which delegator is
aware
Design Patterns
Command pattern
NSInvocation
Undo/redo
Singleton Pattern
NSFileManager
NSApplication
Observer pattern
KVO: Key-Value Observer
Memento
Archiving
Serialization
Adapter pattern
Protocols
Proxy
NSProxy
Design Patterns
Composite
View Hierarchy
Mediator
Controller classes
Decorator
Categories
Abstract Factory
Class Clusters
NSString
NSArray
Façade
NSImage
Bitmap (jpg, png)
Vector (pdf)
Iterator
Fast enumeration
Chain of Responsibility
NSResponder
AppKit Responder Chain
Demo