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Lecture 10 from the Stanford University iPhone Application Programming class was hosted by Alan Cannistraro. He covered memory and performance, two topics that are often overlooked when developing software for mobile devices.

His talk included a demonstration on using Instruments to find memory leaks and memory allocations, the dangers of autorelease objects, and using NSThread and an NSOperationQueue to keep the program running during blocking operations.

If I ever get a halfway functional iPhone app developed, the information about finding memory leaks and threading should prove very useful.

Michael Neel has posted a recap of the CodeStock 2009 developer conference.

CodeStock Wiki

Thanks again to Michael for a humdinger of a conference.

Lecture 9 from the Stanford University iPhone Application Programming class was hosted by Evan Doll, clad in another interesting t-shirt. His topic of the day was persisting data on the iPhone by the use of property lists and SQLite databases, and communicating with web services using the JSON framework.

His talk was incredibly informative and straightforward, and I thought the demos that he used emphasized his points perfectly. Specifically, he covered reading and writing arrays and dictionaries to the iPhone’s file system, use of the NSCoding protocol, basic SQLite operations, and a demo that showed using the json-framework to pull down data from the Flickr web site and display image search results in a list. Finally, at the end, Evan talked about passing data between objects (such as from a list controller to a detail view controller).

The SQLite information should prove extremely valuable, as I am going to want to do some data storage in my iPhone app that goes beyond simply storing preferences in the NSUserDefaults area.