Twitter Code

Twitter API client code in Objective-C

• Canary by Nick Toumpelis - A fully-fledged client, with multi-user support.
  
• MGTwitterEngine by Matt Gemmell - Twitter client library.

On Cocoa Threading

Tutorial on NSOperation and NSOperationQueue From Cocoa Is My Girlfriend

Apple Docs on Threading - You may need a developer account to read these.

Apple Docs on Introspection

This is the page with the best practical discussion of Introspection I have found, and it has a 1 line example: Cocoa Core Competencies: Introspection

Also of interest is the NSObject Protocol document.

Basic Tips iPhone Development

I wish this page had been available when I started iPhone development. Its a nice 50,000 foot description of the basics for someone who is a developer, but is new to Apple development.

But be careful, while its a good intro, there are mistakes and things not explained as clearly as they should be. For example the dot-notation to access instance variables comment. This is "kinda true" but not strictly accurate, the dot-notation is short hand for calling the getter and setter methods of the instance variables, it doesn't access the instance variables directly.

(Matt Legend Gemmell - iPhone Development Emergency Guide)

MapKit Links

Official Apple Documentation

A quick search found this 3 part blog post from a few months ago with simple MapKit examples. The basics of putting up a mapView with current location looks VERY simple.

iPhone game links

I have been sent a few iPhone game related links recently.

• John Carmack on Doom Classic for the iPhone.
  
• Wired article on ngmoco and the effect the App Store has on the traditional gaming business model.

Ownership and memory

From the Apple Developer Connection this section on Object Ownership and Disposal is a must read for new developers.

Cannot use object as a parameter to a method

I was helping someone with a project that was getting a bizarre error message from XCode. The message was Error: Cannot use object as a parameter to a method.

This was some what misleading as the error really referred to what was being returned from the method.

- (NSString)formatPrice:(NSNumber *)priceNumber

The problem was the leading (NSString), which was a typo that should have been (NSString *). Once that change was made, the code compiled and ran correctly.