Architecting a complex iPhone application Alex Cone - Alpha Geek - - - PowerPoint PPT Presentation

CodeFab LLC

iPhone Development & Training

Architecting a complex iPhone application

Alex Cone - Alpha Geek - CodeFab LLC

1 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

So What’s The Problem?

• No Apple examples of full featured

applications

• Books cover implementation of features, but

not architecture

• Developers tend to start with examples and

evolve - leading to poor architecture

2 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Application Tasks

• First Launch
• News Preferences
• Location Acquisition
• Story Load, Caching

3 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Application Tasks

• Relaunch Update
• Recheck Location
• Check Data Freshness
• Update Data

4 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Application Tasks

• Handle User Activity
• Story Reading
• Queries
• Sharing...
• Advertising
• Image Caching
• Saving State...

5 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Design Challenge

• Application Design
• Managing Long Running Tasks
• Managing Concurrency
• Managing

Variable Connectivity

• Managing Data
• Managing State
• Managing Complexity

6 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Advanced Technology

• Singletons
• Notifications
• Threads
• NSOperation/NSOperationQueue

7 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Singletons

• Decoupled Objects
• Data Managers
• Cache Managers
• State Managers
• Specialty Controllers (e.g. LaunchController)
• NSApplication, NSUserDefaults, etc...

8 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Singletons

UIImage *userPic = [[ImageCache shared] cachedImageForKey:[user name]]; ... + (id)shared { static ImageCache *shared = nil; if(!shared){ shared = [[ImageCache allocWithZone:NULL] init]; } return shared; }

9 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Notifications

• More Object Decoupling
• Status Notification
• State Change
• Pub/Sub Events
• NSNotificationCenter

10 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Notifications

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateHUD:) name:@”TweetStatusNotification”

• bject:nil];

...

• (void) updateHUD:(NSNotification *)notification {

if (nil != self.view.window) { NSString *msg = [[notification userInfo] valueForKey:@”Message”]; [[HUDManager shared] showMessage:msg]; }

11 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Threads

• UIKit & Foundation Support
• performAfterDelay
• Background execution with delegate

callback (NSHTTPConnection, etc)

• NSThreads, NSOperationQueues

12 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Process Challenge

• Application Development
• Managing Development Cycles
• Managing Teams
• Managing Releases
• Testing and QA
• Code Reuse

13 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Advanced Process

• Hyper-Agile Methodology
• Daily Iterations
• Partial Pair Programming
• Monthly Releases

14 Wednesday, October 7, 2009

CodeFab LLC

iPhone Development & Training

Advanced Process

• Code Reuse Strategies
• Static Libraries
• Overlapping Projects

Shared Code Project 2 Project 1

15 Wednesday, October 7, 2009

Q&A

CodeFab LLC

iPhone Development & Training

Architecting Complex iPhone Applications

Alex Cone

CodeFab LLC abc@codefab.com

16 Wednesday, October 7, 2009